WorldWideScience

Sample records for charged ion collisions

  1. Holographic heavy ion collisions with baryon charge

    CERN Document Server

    Casalderrey-Solana, Jorge; van der Schee, Wilke; Triana, Miquel

    2016-01-01

    We numerically simulate collisions of charged shockwaves in Einstein-Maxwell theory in anti-de Sitter space as a toy model of heavy ion collisions with non-zero baryon charge. The stress tensor and the baryon current become well described by charged hydrodynamics at roughly the same time. The effect of the charge density on generic observables is typically no larger than 15\\%. %The rapidity profile of the charge is wider than the profile of the local energy density. We find significant stopping of the baryon charge and compare our results with those in heavy ion collision experiments.

  2. Atomic collisions in fusion plasmas involving multiply charged ions

    International Nuclear Information System (INIS)

    A short survey is given on atomic collisions involving multiply charged ions. The basic features of charge transfer processes in ion-ion and ion-atom collisions relevant to fusion plasmas are discussed. (author)

  3. HICS - Highly charged ion collisions with surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Haake, Christian; Peters, Thorsten; Hopster, Johannes; Wucher, Andreas; Schleberger, Marika [Universitaet Duisburg-Essen, Fachbereich Physik, 47057 Duisburg (Germany)

    2009-07-01

    A new ion beam installation with the name HICS (highly charged ions collisions with surfaces) has been constructed to investigate the mechanisms of energy dissipation in a substrate after the impact of highly charged ions. The set-up offers high charge states (up to Ar{sup 16+} or Xe{sup 44+}) and adjustable kinetic energies which can be less than 100 eV/q. These low energies are achieved by a deceleration system which uses a device we call an ion escalator. An evaporation chamber for sample preparation is mounted and a load lock system offers in situ transport to other vacuum systems. To analyse the irradiation effects a time-of-flight system for secondary and neutral mass spectrometry (SIMS/SNMS) is installed. Inner Electronic excitations can be detected with metal-insulator-metal junctions. These detectors offer the possibility to study excitations below the work function which limits the external emission of electrons. First data measured with Ag-AlO{sub x}-Al detectors will be presented.

  4. Experimental results on charge fluctuations in heavy-ion collisions

    CERN Document Server

    Mishra, D K; Netrakanti, P K; Pant, L M; Mohanty, A K

    2016-01-01

    We present a subset of experimental results on charge fluctuation from the heavy-ion collisions to search for phase transition and location of critical point in the QCD phase diagram. Measurements from the heavy-ion experiments at the SPS and RHIC energies observe that total charge fluctuations increase from central to peripheral collisions. The net-charge fluctuations in terms of dynamical fluctuation measure $\

  5. HICS: Highly charged ion collisions with surfaces

    OpenAIRE

    Peters, Thorsten; Haake, Christian; Hopster, Johannes; Sokolovsky, Valentin; Wucher, Andreas; Schleberger, Marika

    2008-01-01

    The layout of a new instrument designed to study the interaction of highly charged ions with surfaces, which consists of an ion source, a beamline including charge separation and a target chamber, is presented here. By varying the charge state and impact velocity of the projectiles separately, the dissipation of potential and kinetic energy at or below the surface can be studied independently. The target chamber offers the use of tunable metal-insulator-metal devices as detectors for internal...

  6. Ion momentum and energy transfer rates for charge exchange collisions

    Science.gov (United States)

    Horwitz, J.; Banks, P. M.

    1973-01-01

    The rates of momentum and energy transfer have been obtained for charge exchange collisions between ion and neutral gases having arbitrary Maxwellian temperatures and bulk transport velocities. The results are directly applicable to the F-region of the ionosphere where 0+ - 0 charge is the dominant mechanism affecting ion momentum and energy transfer.

  7. HICS: Highly charged ion collisions with surfaces

    CERN Document Server

    Peters, Thorsten; Hopster, Johannes; Sokolovsky, Valentin; Wucher, Andreas; Schleberger, Marika

    2008-01-01

    The layout of a new instrument designed to study the interaction of highly charged ions with surfaces, which consists of an ion source, a beamline including charge separation and a target chamber, is presented here. By varying the charge state and impact velocity of the projectiles separately, the dissipation of potential and kinetic energy at or below the surface can be studied independently. The target chamber offers the use of tunable metal-insulator-metal devices as detectors for internal electronic excitation, a timeof-flight system to study the impact induced particle emission and the possibility to transfer samples in situ to a UHV scanning probe microscope. Samples and detectors can be prepared in situ as well. As a first example data on graphene layers on SrTiO3 which have been irradiated with Xe36+ are presented. Key words: highly charged ions, sputtering, AFM, graphene

  8. Production of Charge in Heavy Ion Collisions

    CERN Document Server

    Pratt, Scott; Ratti, Claudia

    2015-01-01

    By analyzing preliminary experimental measurements of charge-balance functions from the STAR Collaboration at the Relativistic-Heavy-Ion Collider (RHIC), it is found that pictures where balancing charges are produced in a single surge, and therefore separated by a single length scale, are inconsistent with data. In contrast, a model that assumes two surges, one associated with the formation of a thermalized quark-gluon plasma and a second associated with hadronization, provides a far superior reproduction of the data. A statistical analysis of the model comparison finds that the two-surge model best reproduces the data if the charge production from the first surge is similar to expectations for equilibrated matter taken from lattice gauge theory. The charges created in the first surge appear to separate by approximately one unit of spatial rapidity before emission, while charges from the second wave appear to have separated by approximately a half unit or less.

  9. Production of charge in heavy ion collisions

    Science.gov (United States)

    Pratt, Scott; McCormack, William Patrick; Ratti, Claudia

    2015-12-01

    By analyzing preliminary experimental measurements of charge-balance functions from the STAR Collaboration at the Relativistic Heavy Ion Collider (RHIC), it is found that scenarios in which balancing charges are produced in a single surge, and therefore separated by a single length scale, are inconsistent with data. In contrast, a model that assumes two surges, one associated with the formation of a thermalized quark-gluon plasma and a second associated with hadronization, provides a far superior reproduction of the data. A statistical analysis of the model comparison finds that the two-surge model best reproduces the data if the charge production from the first surge is similar to expectations for equilibrated matter taken from lattice gauge theory. The charges created in the first surge appear to separate by approximately one unit of spatial rapidity before emission, while charges from the second wave appear to have separated by approximately a half unit or less.

  10. Universal behavior of charged particle production in heavy ion collisions

    Science.gov (United States)

    Phobos Collaboration; Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at sqrt(s_NN) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

  11. Spectator charge splitting of directed flow in heavy ion collisions

    CERN Document Server

    Szczurek, Antoni

    2013-01-01

    We estimate the effect of the spectator charge on distortion of single charged pion distributions as well as on azimuthal anisotropies in heavy ion collisions. A large electromagnetic effect on directed flow $v_1$ is predicted in good agreement with existing WA98 as well as RHIC data. This effect results in a splitting of $v_1$ for positive and negative pions. Detailed analysis of this phenomenon may provide new information on the collision dynamics.

  12. MULTIPLY CHARGED IONS COLLISIONS WITH ATOMS INTO EXCITED STATES

    Institute of Scientific and Technical Information of China (English)

    PanGuangyan

    1990-01-01

    The emission spectra in collisions between Ions and Atoms have been measured by an Optical Multichannel Analysis System (OMA).The experimental results demonstrate that there are two channels of excitation in collision between single charged ions and atoms and three channels of excitation in collision between double charged ions and atoms.Emission cross cestions and excitation cross sections have been obtained.K.Kadota et al and R.Shingal et al suggested that,under the appropriate conditions,the H42+-Li and He2++Na collision systems can be used efficiently to produce a laser of Lyman-α(30,4nm) and Lyman-β(25.6nm)lines via cascade to He+(2P)state.

  13. Magnetohydrodynamics and charged currents in heavy ion collisions

    International Nuclear Information System (INIS)

    The hot QCD matter produced in any heavy ion collision with a nonzero impact parameter is produced within a strong magnetic field. We study the imprint the magnetic fields produced in non-central heavy ion collisions leave on the azimuthal distributions and correlations of the produced charged hadrons. The magnetic field is time-dependent and the medium is expanding, which leads to the induction of charged currents due to the combination of Faraday and Hall effects. We find that these currents result in a charge-dependent directed flow v1 that is odd in rapidity and odd under charge exchange. It can be detected by measuring correlations between the directed flow of charged hadrons at different rapidities, 〈v1±(y1)v1±(y2)〉

  14. Collisions of slow highly charged ions with surfaces

    OpenAIRE

    Burgdoerfer, J.; Lemell, C.; Schiessl, K.; Solleder, B.; Reinhold, C.; Tokesi, K.; Wirtz, Ludger

    2006-01-01

    Progress in the study of collisions of multiply charged ions with surfaces is reviewed with the help of a few recent examples. They range from fundamental quasi-one electron processes to highly complex ablation and material modification processes. Open questions and possible future directions will be discussed.

  15. Magnetohydrodynamics and charge identified directed flow in heavy ion collisions

    Science.gov (United States)

    Gürsoy, Umut; Kharzeev, Dmitri; Rajagopal, Krishna

    2016-01-01

    Strong magnetic fields produced in any non-central heavy ion collision are expected to affect the dynamics of the hot QCD matter produced in this collision. The magnetic field is time-dependent and the medium is expanding, which leads to the induction of charged currents due to the combination of Faraday and Hall effects. We study the imprint the magnetic fields produced in non-central heavy ion collisions leave on the azimuthal distributions and correlations of the produced charged hadrons by employing an analytic solution to hydrodynamics combined with the electromagnetic effects in a perturbative fashion. We use the Cooper-Frye freeze-out procedure on an isothermal freeze-out surface to obtain the azimuthal hadron distributions. We find that the charged currents induced by the present of the electromagnetic fields result in a charge-dependent directed flow v1 that is odd in rapidity and odd under charge exchange. It can be detected by measuring correlations between the directed flow of charged hadrons at different rapidities, .

  16. Mass and charge distribution in heavy-ion collisions

    International Nuclear Information System (INIS)

    A statistical model based on the independent particle picture is used to calculate mass and charge distributions in deep inelastic heavy-ion collisions. Different assumptions on volume and charge equilibrations are compared with measured variances of charge distributions. One combination of assumptions is clearly favoured by experiment, and gives a reasonable description of the variance versus energy loss curves up to energy losses of about 200 MeV in the heavy systems Kr+Ho and Xe+Bi, and up to about 60 MeV for the light system Ar+Ca

  17. Medium effects on charged pion ratio in heavy ion collisions

    CERN Document Server

    Ko, Che Ming; Xu, Jun

    2010-01-01

    We have recently studied in the delta-resonance--nucleon-hole model the dependence of the pion spectral function in hot dense asymmetric nuclear matter on the charge of the pion due to the pion p-wave interaction in nuclear medium. In a thermal model, this isospin-dependent effect enhances the ratio of negatively charged to positively charged pions in neutron-rich nuclear matter, and the effect is comparable to that due to the uncertainties in the theoretically predicted stiffness of nuclear symmetry energy at high densities. This effect is, however, reversed if we also take into account the s-wave interaction of the pion in nuclear medium as given by chiral perturbation theory, resulting instead in a slightly reduced ratio of negatively charged to positively charged pions. Relevance of our results to the determination of the nuclear symmetry energy from the ratio of negatively to positively charged pions produced in heavy ion collisions is discussed.

  18. Medium effects on charged pion ratio in heavy ion collisions

    International Nuclear Information System (INIS)

    We have recently studied in the delta-resonance–nucleon-hole model the dependence of the pion spectral function in hot dense asymmetric nuclear matter on the charge of the pion due to the pion p-wave interaction in nuclear medium. In a thermal model, this isospin-dependent effect enhances the ratio of negatively charged to positively charged pions in neutron-rich nuclear matter, and the effect is comparable to that due to the uncertainties in the theoretically predicted stiffness of nuclear symmetry energy at high densities. This effect is, however, reversed if we also take into account the s-wave interaction of the pion in nuclear medium as given by chiral perturbation theory, resulting instead in a slightly reduced ratio of negatively charged to positively charged pions. Relevance of our results to the determination of the nuclear symmetry energy from the ratio of negatively to positively charged pions produced in heavy ion collisions is discussed. (author)

  19. Transfer of momentum, mass and charge in heavy ion collisions

    International Nuclear Information System (INIS)

    A model for the first two phases of heavy ion collisions based on the transport of single nucleons through the window between the two scattering nuclei is described in some detail. It is pointed out that the model can account simultaneously for a large portion of the energy transfer from relative to intrinsic motion and for the observed variances in mass and charge numbers for reaction times up to the order of 10-21 s. (P.L.)

  20. Correlated charge-changing ion-atom collisions

    International Nuclear Information System (INIS)

    This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant DE-FG02-87ER13778 from March 16, 1991 through March 15, 1992. This work involves the experimental investigation of fundamental atomic processes in collisions of charged projectiles with neutral targets or electrons, with particular emphasis on two-electron interactions and electron correlation effects. Processes involving combinations of excitation, ionization, and charge transfer are investigated utilizing coincidence techniques in which projectiles charge-changing events are associated with x-ray emission, target recoil ions, or electron emission. New results have been obtained for studies involving (1) resonant recombination of atomic ions, (2) double ionization of helium, and (3) continuum electron emission. Experiments were conducted using accelerators at the Lawrence Berkeley Laboratory, Argonne National Laboratory, Michigan State University, Western Michigan University, and the Institute of Nuclear Research, Debrecen, Hungary. Brief summaries of work completed and work in progress are given in this report

  1. On charge transfer in ion-atom collisions at intermediate collision velocities

    International Nuclear Information System (INIS)

    The authors study charge transfer at intermediate energies for multielectron ion-atom collisions within the coupled-state impact-parameter method. They point out the importance of assumptions about electronic relaxation by comparing various calculations of cross sections for KK charge transfer in F9+ + Si as a test case. In these calculations, either the unrelaxed Hamiltonian of the atomic model or a relaxed molecular Hamiltonian has been employed, and two-state atomic or molecular basis sets have been used. To correct for the inadequacy of atomic orbitals for close collisions at intermediate energies, the authors propose to add orbitals of the united atom at the two collision centers. With such an atomic basis set, quasimolecular behavior of the system is represented sufficiently well. The authors report on results for the collision system H+ + He+ for which calculations with large molecular and atomic basis sets exist

  2. Charge Exchange Collisions between Ultracold Fermionic Lithium Atoms and Calcium Ions

    CERN Document Server

    Haze, Shinsuke; Saito, Ryoichi; Mukaiyama, Takashi

    2014-01-01

    An observation of charge exchange collisions between ultracold fermionic 6Li atoms and 40Ca+ ions is reported. The reaction product of the charge exchange collision is dentified via mass spectrometry where the motion of the ions is excited parametrically. We measure the cross section of the charge exchange collisions between the 6Li atoms in the ground state and the 40Ca+ ions in the ground and metastable excited states. Investigation of the inelastic collision characteristics in the atom-ion mixture is an important step toward ultracold chemistry based on ultracold atoms and ions.

  3. Correlated charge-changing ion-atom collisions

    International Nuclear Information System (INIS)

    This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant DE-FG02-87ER13778 from February 16, 1990 through February 15, 1993. This work involves the experimental investigation of atomic interactions in collisions of charged projectiles with neutral targets or electrons, with particular emphasis on two-electron interactions and electron-correlation effects. The processes studied are of interest both from fundamental and applied points of view. In the latter case, results are obtained which are relevant to the understanding of laboratory and astrophysical plasmas, highly-excited (Rydberg) and continuum states of atoms and ions, atomic structure effects, the interaction of ions with surfaces, and the development of heavy-ion storage-rings. The results obtained have provided the basis for several M.A. thesis projects at Western Michigan and several Ph.D. dissertation projects are currently underway. Summaries of work completed and work in progress are given below in Section II. This research has resulted in 26 papers (in print and in press), 12 invited presentations at national and international meetings, and 28 contributed presentations as detailed in Section III

  4. Systematics of Charged Particle Production in Heavy-Ion Collisions with the PHOBOS Detector at Rhic

    Science.gov (United States)

    Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Corbo, J.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hicks, D.; Hofman, D.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Rafelski, M.; Rbeiz, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2002-03-01

    The multiplicity of charged particles produced in Au+Au collisions as a function of energy, centrality, rapidity and azimuthal angle has been measured with the PHOBOS detector at RHIC. These results contribute to our understanding of the initial state of heavy ion collisions and provide a means to compare basic features of particle production in nuclear collisions with more elementary systems.

  5. Fragmentation of molecules under charge-changing collisions of a few MeV heavy ions

    International Nuclear Information System (INIS)

    We investigated molecular fragmentation of CO and C2H2 molecules by impact of various fast heavy ions. Fragment ions produced in electron capture and loss collisions of projectile ions were measured in coincidence with final projectile charge states. Data acquisition using position sensitive detection system allows us to obtain 3D momentum imaging of fragment ions and kinetic energy release (KER) in various charge-changing collisions. It was found that the KER spectra show strong dependence on the type of charge-changing collisions. This may be caused by the difference of impact parameters associated with individual charge-changing collisions. Moreover we revealed the different fragmentation pathway between ion impacts and photoionization

  6. Collision phenomena involving highly-charged ions in astronomical objects

    Science.gov (United States)

    Chutjian, A.

    2001-01-01

    A description of the role of highly charged ions in various astronomical objects; includes the use of critical quantities such as cross sections for excitation, charge-exchange, X-ray emission, radiative recombination (RR) and dielectronic recombination (DR); and lifetimes, branching ratios, and A-values.

  7. Overview on collision processes of highly charged ions with atoms present status and problems

    International Nuclear Information System (INIS)

    This paper provides a brief discussion on the present status of the collision physics of highly charged ions with atoms. The emphasis is on the main achievements in understanding and describing the most important collision processes, and as charge transfer, ionization and Auger-type processes, and even more on those open problems which, due either to their scientific or practical importance, represent challenges to current research in this field. The paper concentrates on general ideas and problems whose development and solutions have advanced or will advance our basic understanding of the collision dynamics of multiply charged ions with atoms

  8. Fragmentation processes of OCS in collision with highly charged ions

    International Nuclear Information System (INIS)

    Fragmentation of (OCS)3+ and (OCS)4+ produced by 120 keV Ar8+ collision was studied by using a position-sensitive time-of-flight (PS-TOF) method. We identified stepwise processes involving CO2+ and CS2+ metastable species as well as the concerted process (simultaneous breakup of the two bonds). For the (OCS)4+ events, the stepwise processes were found for fragmentation channels containing a doubly-charged terminal atom

  9. Excitation of atoms and molecules in collisions with fast, highly charged ions

    International Nuclear Information System (INIS)

    This paper discusses the following topics: charge distributions for Ar recoil-ions produced in one- and two-electron capture collisions by Oq+ projectiles; charge distributions of He, Ne, and Ar recoil-ions produced in collisions with 10 to 30 MeV/u N7+ ions; studies of recoil ions produced in collisions of 40 MeV Ar13+ with atomic and molecular targets; two-fragment coincidence studies of molecular dissociation induced by heavy ion collisions; resonant electron transfer to double K-vacancy states in oxygen compounds; quenching of metastable states in fast Mg projectiles; and design and construction of an atomic physics beamline for the ECR ion source

  10. Saturation effects in charge-changing collisions with multiply-charged C and O ions

    International Nuclear Information System (INIS)

    The electron loss of multiply-charged dressed ions by heavy neutral atoms can have a significant contribution from collisions with small impact parameters. This can render one of the two competing mechanisms which govern the electron loss, i.e. the screening, highly non-perturbative. The other mechanism (antiscreening) is due to electron-electron interactions and its contribution can be treated perturbatively. The dependence of the total electron loss cross sections on the target atomic number, Z2, presents a strong saturation as the value of Z2 increases. Calculations based on the plane wave Born approximation present such a behavior for the antiscreening but not for the screening, since this saturation is related to a non-perturbative regime. In this work we compare data for the total electron loss cross sections of C3+ and O5+ ions by H, He, Ne, Ar, Kr and Xe targets, with energies ranging from 1.0 to 3.5 MeV, with calculations for the screening contribution based on the free-collision model. This comparison shows that, for highly-charged ions, the electron capture and direct target ionization channels play a major role in the description of experimental electron loss data. (orig.)

  11. Tuning Charge Transfer in Ion-Surface Collisions at Hyperthermal Energies.

    Science.gov (United States)

    Yao, Yunxi; Giapis, Konstantinos P

    2016-05-18

    Charge exchange in ion-surface collisions may be influenced by surface adsorbates to alter the charge state of the scattered projectiles. We show here that the positive-ion yield, observed during ion scattering on metal surfaces at low incident energies, is greatly enhanced by adsorbing electronegative species onto the surface. Specifically, when beams of N(+) and O(+) ions are scattered off of clean Au surfaces at hyperthermal energies, no positive ions are observed exiting. Partial adsorption of F atoms on the Au surface, however, leads to the appearance of positively charged primary ions scattering off of Au, a direct result of the increase in the Au work function. The inelastic energy losses for positive-ion exits are slightly larger than the corresponding ionization energies of the respective N and O atoms, which suggest that the detected positive ions are formed by surface reionization during the hard collision event. PMID:26879471

  12. Universal behavior of charged particle production in heavy ion collisions at RHIC energies

    International Nuclear Information System (INIS)

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at √SNN = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/p-barp and e+e- data. ch>/part/2> in nuclear collisions at high energy scales with √s in a similar way as Nch in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions

  13. UNIVERSAL BEHAVIOR OF CHARGED PARTICLE PRODUCTION IN HEAVY ION COLLISIONS AT RHIC ENERGIES

    International Nuclear Information System (INIS)

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at √(sNN) = 19.6, 130 and 200 GeV. Two observations indicate universal behavior of charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/(bar p)p and e+e- data. ch>/part/2> in nuclear collisions at high energy scales with √s in a similar way as Nch in e+e- collisions and has a very weak centrality dependence. These features may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions

  14. Universal behavior of charged particle production in heavy ion collisions at RHIC energies

    Science.gov (United States)

    Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Phobos Collaboration

    2003-04-01

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at √ SNN = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/ overlinepp and e +e - data. / in nuclear collisions at high energy scales with √ s in a similar way as Nch in e +e - collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

  15. The effective charge effect in partially stripped ion-helium collisions

    International Nuclear Information System (INIS)

    The double and single ionization cross section ratios of helium by partially stripped carbon, oxygen and fluorine ions are measured for projectile charge states ranging from +1 to +4 and impact energies from 1.5 MeV to 7.5 MeV. The effective charge effect in partially stripped ion-helium collisions is studied. It is found that the effective charge qeff increases as the impinging energy increases and qeff shows a modest dependence upon the projectile charge state in the present energy range. The projectile charge state, projectile energy, projectile and target electronic state dependences of the effective charge effect may be explained using orbital interpenetrating. (orig.)

  16. Charge separation with fluctuating domains in relativistic heavy-ion collisions

    OpenAIRE

    Shou, Qi-Ye; Ma, Guo-Liang; Ma, Yu-Gang

    2014-01-01

    Charge separation induced by the chiral magnetic effect suggested that some ${\\cal P}$- or ${\\cal CP}$-odd metastable domains could be produced in a QCD vacuum in the early stage of relativistic heavy-ion collisions. Based on a multi-phase transport model, our results suggest that a domain-based scenario with final state interactions can describe the solenoidal tracker at RHIC detector (STAR) measurements of both same- and opposite-charge azimuthal angle correlations, $$, in Au+Au collisions ...

  17. K-Vacancy Production in the Collision of Highly Charged Relativistic Ions With Heavy Atoms

    OpenAIRE

    Khabibullaev, P. K.

    2000-01-01

    A general expression for the cross section of the inelastic collision of relativistic highly charged ion with heavy (relativistic) atoms is obtained using the generalized eikonal approximation. In the ultrarelativistic limit, the obtained formula coincides with a known exact one. As an application of the obtained result, probability and cross section of the K-vacany production in the U92+ - U91+ collision are calculated.

  18. Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions

    International Nuclear Information System (INIS)

    We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement

  19. ELECTRON-CAPTURE IN HIGHLY-CHARGED ION-ATOM COLLISIONS

    NARCIS (Netherlands)

    MORGENSTERN, R

    1993-01-01

    An attempt is made to identify the most important mechanisms responsible for the rearrangement of electrons during collisions between multiply charged ions and atoms at keV energies. It is discussed to which extent the influence of binding energy, angular momentum of heavy particles and electrons, a

  20. Electron and X-ray emission in collisions of multiply charged ions and atoms

    International Nuclear Information System (INIS)

    The author presents experimental results of electron and X-ray emission following slow collisions of multiply charged ions and atoms. The aim of the investigation was to study the mechanisms which are responsible for the emission. (G.T.H.)

  1. Simulations of Ion Velocity Distribution Functions Taken into Account Both Elastic and Charge Exchange Collisions

    CERN Document Server

    Wang, Huihui; Kaganovich, Igor D; Mustafaev, Alexander S

    2016-01-01

    Based on accurate representation of the He+-He differential angular scattering cross sections consisting of both elastic and charge exchange collisions, we performed detailed numerical simulations of the ion velocity distribution functions (IVDF) by Monte Carlo collision method (MCC). The results of simulations are validated by comparison with the experimental data of the mobility and the transverse diffusion. The IVDF simulation study shows that due to significant effect of scattering in elastic collisions IVDF cannot be separated into product of two independent IVDFs in the transverse and parallel to the electric field directions.

  2. Preliminary study for the detection of neutrons in heavy-ion collisions with charged particle detectors

    OpenAIRE

    Auditore L.; Pagano A.; Russotto P.

    2015-01-01

    At Laboratori Nazionali del Sud (LNS) the CHIMERA 4π multidetector has been designed and setup to detect charged particles emitted in heavy ion collisions at intermediate energies. Properties and performances of CHIMERA have been widely demonstrated by published results obtained in the performed experiments. Moreover, in recent years, a new charged particle detector (ChPD) for correlation studies (FARCOS) has been designed, and recently a first prototype has been coupled to CHIMERA, in order ...

  3. Two components in charged particle production in heavy-ion collisions

    Science.gov (United States)

    Bylinkin, A. A.; Chernyavskaya, N. S.; Rostovtsev, A. A.

    2016-02-01

    Transverse momentum spectra of charged particle production in heavy-ion collisions are considered in terms of a recently introduced Two Component parameterization combining exponential ("soft") and power-law ("hard") functional forms. The charged hadron densities calculated separately for them are plotted versus number of participating nucleons, Npart. The obtained dependences are discussed and the possible link between the two component parameterization introduced by the authors and the two component model historically used for the case of heavy-ion collisions is established. Next, the variations of the parameters of the introduced approach with the center of mass energy and centrality are studied using the available data from RHIC and LHC experiments. The spectra shapes are found to show universal dependences on Npart for all investigated collision energies.

  4. Charge state distribution of light ions at glancing collision with solid surface

    International Nuclear Information System (INIS)

    Many experimental results have suggested that the charge state distribution of ions have penetrated through solid is different from that inside the solid. It is important to clarify the physical process taking place at solid surface in order to know the states of ions inside the solid from those observed outside the solid. In the present paper, we report our measurement of charge state distributions of He+ and H2+ ions having been scattered in small angles (less than 40) at surfaces of Au, Ag and C. One of the advantages of the use of the glancing collision of ions at solid surface for the study of ion-surface interaction is that the dwell time of ion near solid surface can be made more than 100 times longer than that in normal transmission experiments. The longer dwell times may alter any contribution of solid surface to electron capture and loss of ions

  5. Collision of highly charged ion with clusters. Simulation study for electronic systems

    Energy Technology Data Exchange (ETDEWEB)

    Yabana, Kazuhiro [Niigata Univ. (Japan)

    1997-05-01

    Collision of highly charged ion with cluster, for example, collision of C{sub 60}-Ar{sup 8+} at E=80 KeV, was simulated by the time-dependence Kohn-Shame equation. The distribution of electron densities and the self-consistent potential were obtained. A part of C{sub 60} potential curve became depressed by the Coulomb force of ion, so that the saddle point was produced on the potential. The behavior of electron transfer on the saddle point was agreed with the classical barrier model. Time-dependent density functional method was explained. (S.Y.)

  6. Collision of highly charged ion with clusters. Simulation study for electronic systems

    International Nuclear Information System (INIS)

    Collision of highly charged ion with cluster, for example, collision of C60-Ar8+ at E=80 KeV, was simulated by the time-dependence Kohn-Shame equation. The distribution of electron densities and the self-consistent potential were obtained. A part of C60 potential curve became depressed by the Coulomb force of ion, so that the saddle point was produced on the potential. The behavior of electron transfer on the saddle point was agreed with the classical barrier model. Time-dependent density functional method was explained. (S.Y.)

  7. Charge-exchange collision dynamics and ion engine grid geometry optimization

    Science.gov (United States)

    Morris, Bradford

    The development of a new three-dimensional model for determining the absolute energy distribution of ions at points corresponding to spacecraft surfaces to the side of an ion engine is presented. The ions resulting from elastic collisions, both charge-exchange (CEX) and direct, between energetic primary ions and thermal neutral xenon atoms are accounted for. Highly resolved energy distributions of CEX ions are found by integration over contributions from all points in space within the main beam formed by the primary ions.The sputtering rate due to impingement of these ions on a surface is calculated. The CEX ions that obtain significant energy (10 eV or more) in the collision are responsible for the majority of the sputtering, though this can depend on the specific material being sputtered. In the case of a molybdenum surface located 60 cm to the side of a 30 cm diameter grid, nearly 90% of the sputtering is due to the 5% of ions with the highest collision exit energies. Previous models that do not model collision energetics cannot predict this. The present results agree with other models and predict that the majority of the ion density is due to collisions where little to no energy is transferred.The sputtering model is combined with a grid-structure model in an optimization procedure where the sputtering rate at specified locations is minimized by adjustment of parameters defining the physical shape of the engine grids. Constraints are imposed that require that the deflection of the grid under a specified load does not exceed a maximum value, in order to ensure survivability of the grids during launch. To faciliate faster execution of the calculations, simplifications based on the predicted behavior of the CEX ions are implemented. For diametrically opposed sputtering locations, a rounded barrel-vault shape reduces the expected sputtering rate by up to 30% in comparison to an NSTAR-shaped grid.

  8. Charged Particle Multiplicity and Open Heavy Flavor Physics in Relativistic Heavy Ion Collisions at the LHC

    Science.gov (United States)

    Chen, Yujiao

    In this thesis, two independent measurements are presented: the measurements of centrality dependence and pseudo-rapidity dependence of charged particle multiplicities, and the measurements of centrality dependence of open heavy flavor suppression. These measurements are carried out with the Pb+Pb collisions data at the LHC energy sNN = 2.76 TeV with the ATLAS detector. For the charged particle measurements, charged particles are reconstructed with two algorithms (2-point "tracklet" and full tracking) from the pixel detector only. Measurements are presented of the per-event charged particle density distribution, dNch /deta and the average charged particle multiplicity in the pseudo-rapidity interval |eta| measurements at the LHC and RHIC. The variation of the mid-rapidity charged particle yield per colliding nucleon pair with the number of participants is consistent with the lower sNN results measured at RHIC. The shape of the dNch/deta distribution is found to be independent of centrality within the systematic uncertainties of the measurement. For the open heavy flavor suppression measurements, muons identified by the muon spectrometer are classified as heavy flavor decays and background contributions by using a fitting procedure with templates from Monte Carlo samples. Results are presented for the per-event muon yield as a function of muon transverse momentum, p T, over the range of 4 measure, muon production from heavy quark decays is found to be suppressed by a centrality-dependent factor that increases smoothly from peripheral to central collisions. Muon production is suppressed by approximately a factor of two in central collisions relative to peripheral collisions. Within the experimental errors, the observed suppression is independent of muon pT for all centralities. Furthermore, the p T dependence of the relative muon yields in Pb+Pb collisions to p+p collisions with the same center of mass collision energy per nucleon is presented by the nuclear

  9. Energy losses of fast heavy multiply charged structural ions in collisions with complex atoms

    Science.gov (United States)

    Matveev, V. I.; Sidorov, D. B.

    2007-07-01

    A nonperturbatve theory of energy losses of fast heavy multiply charged structural ions in collisions with neutral complex atoms is elaborated with allowance for simultaneous excitations of ionic and atomic electron shells. Formulas for the effective deceleration that are similar to the well-known Bethe-Bloch formulas are derived. By way of example, the energy lost by partially stripped U q+ ions (10 ≤ q ≤ 70) colliding with argon atoms and also the energy lost by Au, Pb, and Bi ions colliding with various targets are calculated. The results of calculation are compared with experimental data.

  10. Characterization of charge-exchange collisions between ultracold $\\rm{^6Li}$ atoms and $\\rm{^{40}Ca^+}$ ions

    CERN Document Server

    Saito, R; Sasakawa, M; Nakai, R; Raoult, M; Silva, H Da; Dulieu, O; Mukaiyama, T

    2016-01-01

    We investigate the energy dependence and the internal-state dependence of the charge-exchange collision cross sections in a mixture of $^6$Li atoms and $^{40}$Ca$^+$ ions in the collision energy range from 0.2 mK to 1 K. Deliberately excited ion micromotion is used to control the collision energy of atoms and ions. The energy dependence of the charge-exchange collision cross section obeys the Langevin model in the temperature range of the current experiment, and the measured magnitude of the cross section is correlated to the internal state of the $^{40}$Ca$^+$ ions. Revealing the relationship between the charge-exchange collision cross sections and the interaction potentials is an important step toward the realization of the full quantum control of the chemical reactions at an ultralow temperature regime.

  11. Preliminary study for the detection of neutrons in heavy-ion collisions with charged particle detectors

    Directory of Open Access Journals (Sweden)

    Auditore L.

    2015-01-01

    Full Text Available At Laboratori Nazionali del Sud (LNS the CHIMERA 4π multidetector has been designed and setup to detect charged particles emitted in heavy ion collisions at intermediate energies. Properties and performances of CHIMERA have been widely demonstrated by published results obtained in the performed experiments. Moreover, in recent years, a new charged particle detector (ChPD for correlation studies (FARCOS has been designed, and recently a first prototype has been coupled to CHIMERA, in order to test performances in view of correlation measurements in coincidence with 4π detectors. Simultaneous neutrons and charged particles detection in heavy ion collisions represents an important experimental progress for future experiments to be performed with both stable and exotic nuclei. In order to investigate about this possibility, simple Monte Carlo simulations have been performed. Preliminary simulations have been carried out by means of MCNPX transport code to evaluate the perturbation effects, including cross-talk and time response, induced in CHIMERA and/or FARCOS Si-CsI(Tl telescopes on (typical 20MeV neutron signals coming froma typical reaction in heavy ion collisions at the Fermi energy. Moreover, first data analysis results of the INKIISSY experiment indicates sizable probability to detect neutrons by properly shadowing CHIMERA Si-CsI(Tl telescopes. Analysis is still in progress.

  12. Charged particle multiplicity in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    What follows is a brief overview of the E814 silicon multiplicity detector and some of the data taken with it during a June 89 heavy ion physics run at the BNL AGS. The beam was 14.6 GeV/c/u 28Si on targets of Pb, Cu, and Al. For the data presented below all of the target thicknesses were 1.2% of a Si interaction length. All of the data shown below are still in analysis and none are final

  13. Charge-state dependence of electron loss from H by collisions with heavy, highly stripped ions

    International Nuclear Information System (INIS)

    Theoretical calculations, confirmed by experimental measurements, are used to obtain a new scaling for electron loss from a hydrogen atom in collision with a heavy, highly stripped ion. The calculations cover the energy range 50 to 5000 keV/amu and charge states q from 1 to 50. The experiments are in the range 108 to 1140 keV/amu and charge states 3 to 22. A simple analytic expression that describes the electron-loss cross section for 1 < or = q < or = 50 in the energy range 50 to 5000 keV/amu is presented

  14. Molecular orientation effect on the fragmentation of C2H4 in charge-changing collisions of carbon ions

    International Nuclear Information System (INIS)

    We report a role of molecular orientation in collision-induced fragmentation of C2H4 molecule under conditions of electron loss and capture collisions of C2+ ions at an energy of 857keV (v=1.69 a.u.). Coincidence measurements of fragment ions from C2H4 and charge-selected projectile ions were performed by means of a momentum three-dimensional imaging technique. The effect of molecular orientation is observed rather strongly in all the charge-changing collisions investigated. The experimental data are fitted to a newly developed formula which is often used to predict the orientation effect of diatomic molecules. (author)

  15. Beam energy dependence of pseudorapidity distributions of charged particles produced in relativistic heavy-ion collisions

    Science.gov (United States)

    Basu, Sumit; Nayak, Tapan K.; Datta, Kaustuv

    2016-06-01

    Heavy-ion collisions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN probe matter at extreme conditions of temperature and energy density. Most of the global properties of the collisions can be extracted from the measurements of charged-particle multiplicity and pseudorapidity (η ) distributions. We have shown that the available experimental data on beam energy and centrality dependence of η distributions in heavy-ion (Au +Au or Pb +Pb ) collisions from √{sNN}=7.7 GeV to 2.76 TeV are reasonably well described by the AMPT model, which is used for further exploration. The nature of the η distributions has been described by a double Gaussian function using a set of fit parameters, which exhibit a regular pattern as a function of beam energy. By extrapolating the parameters to a higher energy of √{sNN}=5.02 TeV, we have obtained the charged-particle multiplicity densities, η distributions, and energy densities for various centralities. Incidentally, these results match well with some of the recently published data by the ALICE Collaboration.

  16. Hydrodynamics with chiral anomaly and charge separation in relativistic heavy ion collisions

    CERN Document Server

    Yin, Yi

    2015-01-01

    Matter with chiral fermions is microscopically described by theory with quantum anomaly and macroscopically described (at low energy) by anomalous hydrodynamics. For such systems in the presence of external magnetic field and chirality imbalance, a charge current is generated along the magnetic field direction --- a phenomenon known as the Chiral Magnetic Effect (CME). The quark-gluon plasma created in relativistic heavy ion collisions provides an (approximate) example, for which the CME predicts a charge separation perpendicular to the collisional reaction plane. Charge correlation measurements designed for the search of such signal have been done at RHIC and the LHC for which the interpretations, however, remain unclear due to contamination by background effects that are collective flow driven, theoretically poorly constrained, and experimentally hard to separate. Using anomalous (and viscous) hydrodynamic simulations, we make a first attempt at quantifying contributions to observed charge correlations from...

  17. Ionization and single electron capture in collision of highly charged Ar16+ ions with helium

    Institute of Scientific and Technical Information of China (English)

    Wang Fei; Gou Bing-Cong

    2008-01-01

    This paper uses the two-centre atomic orbital close-coupling method to study the ionization and the single electron capture in collision of highly charged Ar16+ ions with He atoms in the velocity range of 1.2-1.9 a.u.. The relative importance of single ionization (SI) to single capture (SC) is explored. The comparison between the calculation and experimental data shows that the SI/SC cross section ratios from this work are in good agreement with experimental data. The total single electron ionization cross sections and the total single electron capture cross sections are also given for this collision. The investigation of the partial electron capture cross section shows a general tendency of capture to larger n and l with increasing velocity from 1.2 to 1.9 a.u..

  18. Fluctuations of conserved charges in relativistic heavy ion collisions: An introduction

    CERN Document Server

    Asakawa, Masayuki

    2015-01-01

    Bulk fluctuations of conserved charges measured by event-by-event analysis in relativistic heavy ion collisions are observables which are believed to carry significant information on the primordial thermodynamics of the hot medium created by the collisions. Active studies have been done recently experimentally, theoretically, and on the lattice. In particular, non-Gaussianity of the fluctuations aquires much attention recently. In this review, we give a pedagogical introduction to these physics, and overview recent developments in this field of research. Starting from the definition of cumulants, basic concepts in fluctuation physics, such as thermal fluctuations in statistical mechanics and time evolution of fluctuations in diffusive systems, are described. Physics which are expected to occur in the QCD phase diagram and their measurement by event-by-event analyses are also elucidated.

  19. Fluctuations in Charged Particle Multiplicities in Relativistic Heavy-Ion Collisions

    CERN Document Server

    Mukherjee, Maitreyee; Choudhury, Subikash; Nayak, Tapan K

    2016-01-01

    Multiplicity distributions of charged particles and their event-by-event fluctuations have been compiled for relativistic heavy-ion collisions from the available experimental data at Brookhaven National Laboratory and CERN and also by the use of an event generator. Multiplicity fluctuations are sensitive to QCD phase transition and to the presence of critical point in the QCD phase diagram. In addition, multiplicity fluctuations provide baselines for other event-by-event measurements. Multiplicity fluctuation expressed in terms of the scaled variance of the multiplicity distribution is an intensive quantity, but is sensitive to the volume fluctuation of the system. The importance of the choice of narrow centrality bins and the corrections of centrality bin width effect for controlling volume fluctuations have been discussed. It is observed that the mean and width of the multiplicity distributions monotonically increase as a function of increasing centrality at all collision energies, whereas the multiplicity ...

  20. Fluctuations of conserved charges in relativistic heavy ion collisions: An introduction

    Science.gov (United States)

    Asakawa, Masayuki; Kitazawa, Masakiyo

    2016-09-01

    Bulk fluctuations of conserved charges measured by event-by-event analysis in relativistic heavy ion collisions are observables which are believed to carry significant amount of information on the hot medium created by the collisions. Active studies have been done recently experimentally, theoretically, and on the lattice. In particular, non-Gaussianity of the fluctuations has acquired much attention recently. In this review, we give a pedagogical introduction to these issues, and survey recent developments in this field of research. Starting from the definition of cumulants, basic concepts in fluctuation physics, such as thermal fluctuations in statistical mechanics and time evolution of fluctuations in diffusive systems, are described. Phenomena which are expected to occur in finite temperature and/or density QCD matter and their measurement by event-by-event analyses are also elucidated.

  1. C60 fragmentation in charge-changing collisions with slow Au+ ions

    International Nuclear Information System (INIS)

    We investigated ionization and fragmentation of C60 in the charge-changing collisions of 2.0 keV/amu Au+ ions with C60 molecules. We performed simultaneous measurements of product ions, the number of secondary electrons, and a charge-selected outgoing Au projectile. The production of C60+ ions was predominant in the single-electron capture (1-capture) process. In contrast, multifragmentation of C60 was predominant in the single-electron loss (1-loss) process. The multifragmentation was enhanced in the 1-loss process compared with the 1-capture process when the same number of electrons was emitted from C60. This enhancement was also observed when a fast Si ion traveled close to a carbon nucleus [T. Majima et al., Phys. Rev. A 74, 033201 (2006)]. The 1-loss process of slow Au+ ions is considered to occur closer to a carbon nucleus than does the 1-capture process. Multifragmentation of C60 is caused by internal electronic excitation although it is probably assisted by nuclear stopping when, at least, the electronic excitation of C60 is small.

  2. Excitation of atoms and molecules in collisions with highly charged ions

    International Nuclear Information System (INIS)

    A study of the double ionization of He by high-energy N7+ ions was extended up in energy to 40 MeV/amu. Coincidence time-of-flight studies of multicharged N2, O2, and CO molecular ions produced in collisions with 97-MeV Ar14+ ions were completed. Analysis of the total kinetic energy distributions and comparison with the available data for CO2+ and CO3+ from synchrotron radiation experiments led to the conclusion that ionization by Ar-ion impact populates states having considerably higher excitation energies than those accessed by photoionization. The dissociation fractions for CO1+ and CO2+ molecular ions, and the branching ratios for the most prominent charge division channels of CO2+ through CO7+ were determined from time-of-flight singles and coincidence data. An experiment designed to investigate the orientation dependence of dissociative multielectron ionization of molecules by heavy ion impact was completed. Measurements of the cross sections for K-shell ionization of intermediate-Z elements by 30-MeV/amu H, N, Ne, and Ar ions were completed. The cross sections were determined for solid targets of Z = 13, 22, 26, 29, 32, 40, 42, 46, and 50 by recording the spectra of K x rays with a Si(Li) spectrometer

  3. Fluctuations in charged particle multiplicities in relativistic heavy-ion collisions

    Science.gov (United States)

    Mukherjee, Maitreyee; Basu, Sumit; Choudhury, Subikash; Nayak, Tapan K.

    2016-08-01

    Multiplicity distributions of charged particles and their event-by-event fluctuations have been compiled for relativistic heavy-ion collisions from the available experimental data at Brookhaven National Laboratory and CERN and also by the use of an event generator. Multiplicity fluctuations are sensitive to QCD phase transition and to the presence of a critical point in the QCD phase diagram. In addition, multiplicity fluctuations provide baselines for other event-by-event measurements. Multiplicity fluctuation expressed in terms of the scaled variance of the multiplicity distribution is an intensive quantity, but is sensitive to the volume fluctuation of the system. The importance of the choice of narrow centrality bins and the corrections of the centrality bin-width effect for controlling volume fluctuations have been discussed. It is observed that the mean and width of the multiplicity distributions monotonically increase as functions of increasing centrality at all collision energies, whereas the multiplicity fluctuations show minimal variations with centrality. The beam-energy dependence shows that the multiplicity fluctuations have a slow rise at lower collision energies and remain constant at higher energies.

  4. Dynamics in charge transfer and ionization processes in fast ion-helium collisions

    International Nuclear Information System (INIS)

    In the course of this work transfer ionization (TI), radiative electron capture (REC), and single ionization (SI) in fast ion-helium collisions have been studied. For this purpose, two experimental techniques, a coincident ion-electron momentum spectrometer, namely a Reaction Microscope (REMI) and the heavy ion storage ring TSR, providing excellent beam properties, have been combined. In TI, i.e. the ejection of one plus the capture of a second target electron, the role of electron-electron correlations is of particular interest. In order to unravel different correlated as well as uncorrelated mechanisms, differential data has been recorded for different perturbations (projectile charge to speed ratio). For the first time strong evidence of a recently proposed, correlated TI process was found experimentally. In a second, pioneering experiment it has been attempted to perform the first kinematically complete measurement on REC. Here, an electron from the target is captured by the projectile simultaneously emitting a photon. In order to observe the emerging photons, a detector covering a large solid angle has been designed and implemented in the REMI. Although three particle coincidences have been recorded between recoil ions, projectile ions, and photons, experimental proof of the acquisition of REC coincidences was prevented due to limited statistics. Finally, in studies on SI, the influence of the projectile beam coherence properties on the collision dynamics has been investigated. The pronounced differences to earlier data taken with a projectile beam with much smaller coherence length provide evidence for its influence on the ionization dynamics, which is generally neglected in theoretical calculations. These results could pave the way to a final resolution of the long standing question on the origin of the discrepancies between theory and experiment in fully differential cross sections.

  5. Dissociation of Methanol and Acetylene by slow Highly Charged Ion Collision

    International Nuclear Information System (INIS)

    We report here the results of dissociation of multiple charged methanol and acetylene molecules in collision with 1.2 MeV Ar8+ projectiles. We observed a wide range of dissociation products from the TOF spectrum starting from undissociated molecular ions, fragments losing an hydrogen atom due to breakage of C-H and/or O-H bonds, to complete rupture of C-C and C-O skeletons for the respective molecules. From the coincidence map of the fragments, we could separate out the different dissociation channels between carbon and oxygen ionic fragments as well as complete two-body dissociation events. The most striking feature in the breakup of CH3OH is the formation of H2+ and H3+ due to intramolecular rearrangement of the C-H bonds within the methyl group. In dissociative ionization studies of C2H2, we observed a diatom-like behaviour of the C-C charged complex as evidenced from the measured slopes of the coincidence islands for carbon atomic charged fragments and theoretical values determined from the charge and momentum distribution of the correlated particles. The shape and orientation of the islands give further information about the momentum balance in the fragmentation process in two-body dissociation

  6. Hydrodynamics with chiral anomaly and charge separation in relativistic heavy ion collisions

    Science.gov (United States)

    Yin, Yi; Liao, Jinfeng

    2016-05-01

    Matter with chiral fermions is microscopically described by theory with quantum anomaly and macroscopically described (at low energy) by anomalous hydrodynamics. For such systems in the presence of external magnetic field and chirality imbalance, a charge current is generated along the magnetic field direction - a phenomenon known as the Chiral Magnetic Effect (CME). The quark-gluon plasma created in relativistic heavy ion collisions provides an (approximate) example, for which the CME predicts a charge separation perpendicular to the collisional reaction plane. Charge correlation measurements designed for the search of such signal have been done at RHIC and the LHC for which the interpretations, however, remain unclear due to contamination by background effects that are collective flow driven, theoretically poorly constrained, and experimentally hard to separate. Using anomalous (and viscous) hydrodynamic simulations, we make a first attempt at quantifying contributions to observed charge correlations from both CME and background effects in one and same framework. The implications for the search of CME are discussed.

  7. Electron Capture in Collisions of Slow Highly Charged Ions with an Atom and a Molecule: Processes and Fragmentation Dynamics

    OpenAIRE

    Xavier Husson; Dominique Hennecart; Xavier Fléchard; Jean-Yves Chesnel; Amine Cassimi; Lamri Adoui; Medhi Tarisien; Przemyslaw Sobocinski; Jimmy Rangama; Guillaume Laurent; François Frémont

    2002-01-01

    Abstract : Processes involved in slow collisions between highly charged ions (HCI) and neutral targets are presented. First, the mechanisms responsible for double electron capture are discussed. We show that, while the electron-nucleus interaction is expected to be dominant at projectile velocities of about 0.5 a.u., the electron-electron interaction plays a decisive role during the collision and gains importance when the projectile velocity decreases. This interaction has also to be invoked ...

  8. Extension of charge-state-distribution calculations for ion-solid collisions towards low velocities and many-electron ions

    Science.gov (United States)

    Lamour, E.; Fainstein, P. D.; Galassi, M.; Prigent, C.; Ramirez, C. A.; Rivarola, R. D.; Rozet, J.-P.; Trassinelli, M.; Vernhet, D.

    2015-10-01

    Knowledge of the detailed evolution of the whole charge-state distribution of projectile ions colliding with targets is required in several fields of research such as material science and atomic and nuclear physics but also in accelerator physics, and in particular in regard to the several foreseen large-scale facilities. However, there is a lack of data for collisions in the nonperturbative energy domain and that involve many-electron projectiles. Starting from the etacha model we developed [Rozet et al., Nucl. Instrum. Methods Phys. Res., Sect. B 107, 67 (1996), 10.1016/0168-583X(95)00800-4], we present an extension of its validity domain towards lower velocities and larger distortions. Moreover, the system of rate equations is able to take into account ions with up to 60 orbital states of electrons. The computed data from the different new versions of the etacha code are compared to some test collision systems. The improvements made are clearly illustrated by 28.9 MeV u-1P b56 + ions, and laser-generated carbon ion beams of 0.045 to 0.5 MeV u-1 , passing through carbon or aluminum targets, respectively. Hence, those new developments can efficiently sustain the experimental programs that are currently in progress on the "next-generation" accelerators or laser facilities.

  9. I. Charge exchange collisions of highly stripped ions with atomic hydrogen. II. Development of a three-stage double tandem accelerator-decelerator system for low energy, highly stripped ions. Final report, March 1, 1977-May 30, 1981

    International Nuclear Information System (INIS)

    The first measurements of charge exchange (electron transfer) in kiloelectron-volt-energy highly stripped boron, carbon, nitrogen and oxygen ion collisions with atoms have been extended to additional collision energies and charge values for the ions. A first accelerator-decelerator source of very highly stripped ions has been developed, and its usefulness in charge exchange studies established

  10. Charged particle density distributions in Au + Au collisions at relativistic heavy-ion collider energies

    Indian Academy of Sciences (India)

    Fauad Rami

    2003-05-01

    Charged particle pseudorapidity distributions have been measured in Au + Au collisions using the BRAHMS detector at RHIC. The results are presented as a function of the collision centrality and the center of mass energy. They are compared to the predictions of different parton scattering models and the important role of hard scattering processes at RHIC energies is discussed.

  11. Charged-particle multiplicity at mid-rapidity in Au–Au collisions at relativistic heavy-ion collider

    Indian Academy of Sciences (India)

    D Silvermyr

    2003-05-01

    The particle density at mid-rapidity is an essential global variable for the characterization of nuclear collisions at ultra-relativistic energies. It provides information about the initial conditions and energy density reached in these collisions. The pseudorapidity densities of charged particles at mid-rapidity in Au + Au collisions at $\\sqrt{S_{NN}}=130$ and 200 GeV at RHIC (relativistic heavy ion collider) have been measured with the PHENIX detector. The measurements were performed using sets of wire-chambers with pad readout in the two central PHENIX tracking arms. Each arm covers one quarter of the azimuth in the pseudorapidity interval || < 0.35. Data is presented and compared with results from proton–proton collisions and nucleus–nucleus collisions at lower energies. Extrapolations to LHC energies are discussed.

  12. Atomic collision experiments utilizing low-velocity, highly-charged ion beams

    International Nuclear Information System (INIS)

    Intense beams of highly-stripped ions are now routinely produced at low velocities using the Brookhaven dual MP-tandems in a unique four-stage accel/decel mode. This mode of operation combines three stages of acceleration, stripping at high energy, and one stage of deceleration to near-zero velocity. To date, experiments have used 10-100 nA beams of bare and few-electron heavy ions at energies as low as 0.2 MeV/amu, and upgrades of the facility should push the lower limit below 0.1 MeV/amu. Recent experiments, such as measurements of charge transfer and x-ray production for S6-16+ on He and Ar at 6-20 MeV and P(b) measurements for MO x-rays produced in Cl16+ + Ar collisions at 20, 10 and 5 MeV have demonstrated the usefulness of highly-stripped, low-velocity projectiles. These experiments and a few possibilities for future experiments are discussed

  13. Charge breeding investigation in EBIS/T and collision study of ions with cold atoms for HITRAP

    International Nuclear Information System (INIS)

    Highly charged ions (HCI) at low velocities or at rest are interesting systems for various atomic physics experiments. For investigations on HCI of heavy stable or radioactive nuclides the HITRAP (Highly charged Ion TRAP) decelerator facility has been set up at GSI to deliver cooled beams of HCI at an energy of 5 keV/q. The HCI are produced in a stripper foil at relativistic energies and are decelerated in several steps at ESR storage ring and HITRAP before they are delivered to experimental setups. One of the experiments is the investigation of multi-electron charge exchange in collisions of heavy HCI with cold atoms using novel MOTRIMS technique. Collision experiments on light ions from an ECR ion source colliding with cold atoms in a MOT have been performed and the results are described. An electron beam ion trap (EBIT) has been tested and optimized for commissioning of the HITRAP physics experiments. The process of charge breeding in the EBIT has been successfully studied with gaseous elements and with an alkaline element injected from an external ion source. (orig.)

  14. Charge breeding investigation in EBIS/T and collision study of ions with cold atoms for HITRAP

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Alexey

    2010-01-29

    Highly charged ions (HCI) at low velocities or at rest are interesting systems for various atomic physics experiments. For investigations on HCI of heavy stable or radioactive nuclides the HITRAP (Highly charged Ion TRAP) decelerator facility has been set up at GSI to deliver cooled beams of HCI at an energy of 5 keV/q. The HCI are produced in a stripper foil at relativistic energies and are decelerated in several steps at ESR storage ring and HITRAP before they are delivered to experimental setups. One of the experiments is the investigation of multi-electron charge exchange in collisions of heavy HCI with cold atoms using novel MOTRIMS technique. Collision experiments on light ions from an ECR ion source colliding with cold atoms in a MOT have been performed and the results are described. An electron beam ion trap (EBIT) has been tested and optimized for commissioning of the HITRAP physics experiments. The process of charge breeding in the EBIT has been successfully studied with gaseous elements and with an alkaline element injected from an external ion source. (orig.)

  15. Fragmentation dynamics of CO23+ investigated by multiple electron capture in collisions with slow highly charged ions

    CERN Document Server

    Neumann, N; Schmidt, L Ph H; Titze, J; Jahnke, T; Czasch, A; Schöffler, M S; Kreidi, K; Jagutzki, O; Schmidt-Böcking, H; Dörner, R

    2010-01-01

    Fragmentation of highly charged molecular ions or clusters consisting of more than two atoms can proceed in an onestep synchronous manner where all bonds break simultaneously or sequentially by emitting one ion after the other. We separated these decay channels for the fragmentation of CO23+ ions by measuring the momenta of the ionic fragments. We show that the total energy deposited in the molecular ion is a control parameter which switches between three distinct fragmentation pathways: the sequential fragmentation in which the emission of an O+ ion leaves a rotating CO2+ ion behind that fragments after a time delay, the Coulomb explosion and an in-between fragmentation - the asynchronous dissociation. These mechanisms are directly distinguishable in Dalitz plots and Newton diagrams of the fragment momenta. The CO23+ ions are produced by multiple electron capture in collisions with 3.2 keV/u Ar8+ ions.

  16. Evaluation of excitation energy and spin from light charged particles multiplicities in heavy-ion collisions

    CERN Document Server

    Steckmeyer, J C; Grotowski, K; Pawowski, P; Aiello, S; Anzalone, A; Bini, M; Borderie, B; Bougault, R; Cardella, G; Casini, G; Cavallaro, S; Charvet, J L; Dayras, R; De Filippo, E; Durand, D; Femin, S; Frankland, J D; Galíchet, E; Geraci, M; Giustolisi, F; Guazzoni, P; Iacono-Manno, M; Lanzalone, G; Lanzan, G; Le Neindre, N; Lo Nigro, S; Lo Piano, F; Olmi, A; Pagano, A; Papa, M; Pârlog, M; Pasquali, G; Piantelli, S; Pirrone, S; Politi, G; Porto, F; Rivet, M F; Rizzo, F; Rosato, E; Roy, R; Sambataro, S; Sperduto, M L; Stefanini, A A; Sutera, C; Tamain, B; Vient, E; Volant, C; Wieleczko, J P; Zetta, L

    2005-01-01

    A simple procedure for evaluating the excitation energy and the spin transfer in heavy-ion dissipative collisions is proposed. It is based on a prediction of the GEMINI evaporation code : for a nucleus with a given excitation energy, the average number of emitted protons decreases with increasing spin, whereas the average number of alpha particles increases. Using that procedure for the reaction 107Ag+58Ni at 52 MeV/nucleon, the excitation energy and spin of quasi-projectiles have been evaluated. The results obtained in this way have been compared with the predictions of a model describing the primary dynamic stage of heavy-ion collisions.

  17. Local vs. non-local energy loss of low energy ions: Influence of charge exchange processes in close collisions

    Energy Technology Data Exchange (ETDEWEB)

    Primetzhofer, D., E-mail: daniel.primetzhofer@physics.uu.se [Ion Physics, Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, Box 516, S-751 20 Uppsala (Sweden); Goebl, D.; Bauer, P. [Institut für Experimentalphysik, Johannes Kepler Universität Linz, A-4040 Linz (Austria)

    2013-12-15

    We investigate the contribution of charge exchange processes in close collisions between projectile and target atoms to the electronic energy loss of low energy ions. We measure the energy loss of slow hydrogen and He ions in ultrathin Al films through which the ions are transmitted before and after backscattering by the atoms of a Ta substrate. The individual contributions to the energy loss are analyzed. The roles of thresholds for reionization and of scattering kinematics as key parameters for the coupling between elastic and inelastic losses are discussed. The implications of the obtained results for different experimental approaches to deduce stopping cross sections are outlined.

  18. Electron emission in collisions of fast highly charged bare ions with helium atoms

    Science.gov (United States)

    Mondal, Abhoy; Mandal, Chittranjan; Purkait, Malay

    2016-01-01

    We have studied the electron emission from ground state helium atom in collision with fast bare heavy ions at intermediate and high incident energies. In the present study, we have applied the present three-body formalism of the three Coulomb wave (3C-3B) model and the previously adopted four-body formalism of the three Coulomb wave (3C-4B). To represent the active electron in the helium atom in the 3C-3B model, the initial bound state wavefunction is chosen to be hydrogenic with an effective nuclear charge. The wavefunction for the ejected electron in the exit channel has been approximated to be a Coulomb continuum wavefunction with same effective nuclear charge. Effectively the continuum-continuum correlation effect has been considered in the present investigation. Here we have calculated the energy and angular distribution of double differential cross sections (DDCS) at low and high energy electron emission from helium atom. The large forward-backward asymmetry is observed in the angular distribution which is explained in terms of the two-center effect (TCE). Our theoretical results are compared with available experimental results as well as other theoretical calculations based on the plain wave Born approximation (PWBA), continuum-distorted wave (CDW) approximation, continuum-distorted wave eikonal-initial state (CDW-EIS) approximation, and the corresponding values obtained from the 3C-4B model [S. Jana, R. Samanta, M. Purkait, Phys. Scr. 88, 055301 (2013)] respectively. It is observed that the four-body version of the present investigation produces results which are in better agreement with experimental observations for all cases.

  19. Electron Capture in Collisions of Slow Highly Charged Ions with an Atom and a Molecule: Processes and Fragmentation Dynamics

    Directory of Open Access Journals (Sweden)

    Xavier Husson

    2002-03-01

    Full Text Available Abstract : Processes involved in slow collisions between highly charged ions (HCI and neutral targets are presented. First, the mechanisms responsible for double electron capture are discussed. We show that, while the electron-nucleus interaction is expected to be dominant at projectile velocities of about 0.5 a.u., the electron-electron interaction plays a decisive role during the collision and gains importance when the projectile velocity decreases. This interaction has also to be invoked in the capture of core electrons by HCI. Finally, the molecular fragmentation of H2 following the impact of HCI is studied.

  20. Fragmentation study of isolated and nanosolvated biomolecules induced by collision with multiply charged ions and neutral particles

    OpenAIRE

    Bernigaud, Virgile

    2009-01-01

    This thesis concerns a gas phase study of the fragmentation of biomolecular systems induced by slow collisions with multiply charged ions (in the keV-region), alkali atoms and rare gases. The main objective was to study the physical processes involved in the dissociation of highly electronically excited systems. In order to elucidate the intrinsic properties of certain biomolecules (porphyrins and amino acids) we have performed experiments in the gas phase with isolated systems. The obtained ...

  1. Dynamics of the Rydberg state population of slow highly charged ions impinging a solid surface at arbitrary collision geometry

    Science.gov (United States)

    Nedeljković, N. N.; Majkić, M. D.; Božanić, D. K.; Dojčilović, R. J.

    2016-06-01

    We consider the population dynamics of the intermediate Rydberg states of highly charged ions (core charge Z\\gg 1, principal quantum number {n}{{A}}\\gg 1) interacting with solid surfaces at arbitrary collision geometry. The recently developed resonant two-state vector model for the grazing incidence (2012 J. Phys. B: At. Mol. Opt. Phys. 45 215202) is extended to the quasi-resonant case and arbitrary angle of incidence. According to the model, the population probabilities depend both on the projectile parallel and perpendicular velocity components, in a complementary way. A cascade neutralization process for {{{Xe}}}Z+ ions, for Z=15{--}45, interacting with a conductive-surface is considered by taking into account the population dynamics. For an arbitrary collision geometry and given range of ionic velocities, a micro-staircase model for the simultaneous calculation of the kinetic energy gain and the charge state of the ion in front of the surface is proposed. The relevance of the obtained results for the explanation of the formation of nanostructures on solid surfaces by slow highly charged ions for normal incidence geometry is briefly discussed.

  2. Low-Energy Charge Transfer in Multiply-Charged Ion-Atom Collisions Studied with the Combined SCVB-MOCC Approach

    Directory of Open Access Journals (Sweden)

    B. Zygelman

    2002-03-01

    Full Text Available A survey of theoretical studies of charge transfer involving collisions of multiply-charged ions with atomic neutrals (H and He is presented. The calculations utilized the quantum-mechanical molecular-orbital close-coupling (MOCC approach where the requisite potential curves and coupling matrix elements have been obtained with the spin-coupled valence bond (SCVB method. Comparison is made among various collision partners, for equicharged systems, where it is illustrated that even for total charge transfer cross sections, scaling-laws do not exist for low-energy collisions (i.e. < 1 keV/amu. While various empirical scaling-laws are well known in the intermediateand high-energy regimes, the multi-electron configurations of the projectile ions results in a rich and varied low-energy dependence, requiring an explicit calculation for each collision-partner pair. Future charge transfer problems to be addressed with the combined SCVB-MOCC approach are briefly discussed.

  3. Transfer ionization cross-sections measured in collisions of highly charged argon ions with neon target

    Institute of Scientific and Technical Information of China (English)

    MA; Xinwen(马新文); LIU; Huiping; (刘惠萍); CHEN; Ximeng; (陈熙萌); YANG; Zhihu; (杨治虎); SHEN; Ziyong; (申自勇); WANG; Youde; (王友德); YU; Deyang; (于得洋); CAI; Xiaohong; (蔡晓红); LIU; Zhaoyuan; (刘兆远)

    2003-01-01

    Multiple electron transfer processes are studied for Arq+ + Ne (q = 8, 9, 11, 12) collisions by using multi-parameter coincidence techniques. Various electron transfer processes are identified experimentally and the related cross-sections are measured. The dependence of transfer ionization cross-sections on the recoil charge states is compared with the results from the modified molecular classical overbarrier model. It is found that the modified model described the experimental results reasonably.

  4. Beam energy dependence of pseudorapidity distributions of charged particles produced in heavy-ion collisions at RHIC and LHC energies

    CERN Document Server

    Basu, Sumit; Datta, Kaustuv

    2016-01-01

    Heavy-ion collisions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN probe matter at extreme conditions of temperature and energy density. Most of the global properties of the collisions can be extracted from the measurements of charged particle multiplicity and pseudorapidity ($\\eta$) distributions. We have shown that the available experimental data on beam energy and centrality dependence of \\Eta-distributions in heavy-ion (Au+Au or Pb+Pb) collisions from \\sNN=7.7 GeV to 2.76 TeV are reasonably well described by the AMPT model, which is used for further exploration. The nature of the \\Eta-distributions has been described by a double Gaussian function using a set of fit parameters, which exhibit a regular pattern as a function of beam energy. By extrapolating the parameters to a higher energy of \\sNN~=~5.02 TeV, we have obtained the charged particle multiplicity densities, \\Eta-distributions and energy densities for various centralities. Incident...

  5. Charge transfer in collisions of Beq+ (q=2-4) and Bq+ (q=3-5) ions with H

    International Nuclear Information System (INIS)

    The charge transfer reactions in collisions of Beq+(q=2-3) and Bq+(q=3-4) ions and atomic hydrogen are investigated by using the quantal molecular orbital close-coupling (QMOCC) and the two-center atomic-orbital close-coupling (TC-AOCC) methods. Total and sub-shells state-selective cross sections are calculated for low and intermediate energy region and compared with other data available. Sets of recommended cross sections, based on the QMOCC and TC-AOCC calculations, are deduced and tabulated for Be2,3+ + H and B3,4+ + H collisions, which provide important atomic data needed in the charge-exchange-recombination spectroscopy diagnostics in magnetic fusion plasmas investigation

  6. Removing flow backgrounds from the charge-separation observable perpendicular to the reaction plane in heavy-ion collisions

    CERN Document Server

    Wen, Fufang; Wang, Gang

    2016-01-01

    Recent charge-dependent azimuthal correlation measurements in high-energy heavy-ion collisions have observed charge-separation signals perpendicular to the reaction plane, and the observations have been related to the chiral magnetic effect (CME). However, the correlation signal is contaminated with the background contributions due to the collective motion (flow) of the collision system, and it remains elusive to effectively remove the background from the correlation. We present a method study with Monte Carlo simulations and a multi-phase transport model, and develop a scheme to reveal the true CME signal via the event-shape engineering with the flow vector, $\\overrightarrow{q}$. An alternative approach using the ensemble averages of observables is also discussed.

  7. Effect of collective response on electron capture and excitation in collisions of highly charged ions with fullerenes.

    Science.gov (United States)

    Kadhane, U; Misra, D; Singh, Y P; Tribedi, Lokesh C

    2003-03-01

    Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions. PMID:12689221

  8. Fragmentation study of isolated and nano-solvated biomolecules induced by collision with multiply charged ions and neutral particles

    International Nuclear Information System (INIS)

    This thesis concerns a gas phase study of the fragmentation of bio-molecular systems induced by slow collisions with multiply charged ions (in the keV-region), alkali atoms and rare gases. The main objective was to study the physical processes involved in the dissociation of highly electronically excited systems. In order to elucidate the intrinsic properties of certain biomolecules (porphyrins and amino acids) we have performed experiments in the gas phase with isolated systems. The obtained results demonstrate the high stability of porphyrins after electron removal and attachment. Furthermore, a dependence of the fragmentation pattern produced by multiply charged ions on the isomeric structure of the alanine molecule has been shown. In a second part of the thesis, a strong influence of the environment of the biomolecule on the fragmentation channels, their modification and their new opening, has been clearly proven. This phenomenon occurs in the presence of other surrounding biomolecules (clusters of nucleobases) as well as for molecules of a solvent (molecules of water, methanol and acetonitrile) in which the biomolecule is embedded. In order to extend these studies to larger systems, a new experimental set-up, based on an electro-spray ion source combined with a quadrupole mass filter has been developed. Due to the successful tests and proposed improvements of the device future experiments will become available concerning the fragmentation of large charged and solvated bio-molecular systems induced by collision processes. (author)

  9. Observation of charge-dependent azimuthal correlations and possible local strong parity violation in heavy-ion collisions

    Science.gov (United States)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betancourt, M. J.; Betts, R. R.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bnzarov, I.; Bonner, B. E.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bridgeman, A.; Bruna, E.; Bueltmann, S.; Burton, T. P.; Cai, X. Z.; Caines, H.; Calderón de La Barca Sánchez, M.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, P.; Clarke, R. F.; Codrington, M. J. M.; Corliss, R.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; de Silva, L. C.; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; Derradi de Souza, R.; Didenko, L.; Djawotho, P.; Dzhordzhadze, V.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunlop, J. C.; Dutta Mazumdar, M. R.; Efimov, L. G.; Elhalhuli, E.; Elnimr, M.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gangadharan, D. R.; Ganti, M. S.; Garcia-Solis, E. J.; Geromitsos, A.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; Heinz, M.; Heppelmann, S.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Humanic, T. J.; Huo, L.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jena, C.; Jin, F.; Jones, C. L.; Jones, P. G.; Joseph, J.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kauder, K.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kikola, D. P.; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Konzer, J.; Kopytine, M.; Koralt, I.; Korsch, W.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Krus, M.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; Lapointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lee, J. H.; Leight, W.; Levine, M. J.; Li, C.; Li, N.; Li, Y.; Lin, G.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; Matulenko, Yu. A.; McDonald, D.; McShane, T. S.; Meschanin, A.; Milner, R.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Pile, P.; Planinic, M.; Ploskon, M. A.; Pluta, J.; Plyku, D.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Pujahari, P. R.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Redwine, R.; Reed, R.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakai, S.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seele, J.; Seger, J.; Selyuzhenkov, I.; Semertzidis, Y.; Seyboth, P.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X.-H.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T. J. M.; Szanto de Toledo, A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarini, L. H.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tlusty, D.; Tokarev, M.; Tram, V. N.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; van Buren, G.; van Nieuwenhuizen, G.; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Videbaek, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, Q.; Wang, X.; Wang, X. L.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Whitten, C., Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xie, W.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yang, Y.; Yepes, P.; Yip, K.; Yoo, I.-K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, S.; Zhang, W. M.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zhu, X.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zuo, J. X.; STAR Collaboration

    2010-05-01

    Parity (P)-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the orbital momentum of the system created in noncentral collisions. To study this effect, we investigate a three-particle mixed-harmonics azimuthal correlator which is a P-even observable, but directly sensitive to the charge-separation effect. We report measurements of this observable using the STAR detector in Au+Au and Cu+Cu collisions at sNN=200 and 62 GeV. The results are presented as a function of collision centrality, particle separation in rapidity, and particle transverse momentum. A signal consistent with several of the theoretical expectations is detected in all four data sets. We compare our results to the predictions of existing event generators and discuss in detail possible contributions from other effects that are not related to P violation.

  10. Centrality and energy dependence of charged-particle multiplicities in heavy ion collisions in the context of elementary reactions

    Science.gov (United States)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J. Van; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2006-08-01

    The PHOBOS experiment at the BNL Relativistic Heavy Ion Collider has measured the total multiplicity of primary charged particles as a function of collision centrality in Au+Au collisions at sNN= 19.6, 130, and 200 GeV. An approximate independence of / on the number of participating nucleons is observed, reminiscent of “wounded nucleon” scaling (Nch∝Npart) observed in proton-nucleus collisions. Unlike p+A, the constant of proportionality does not seem to be set by the pp/p¯p data at the same energy. Rather, there seems to be a surprising correspondence with the total multiplicity measured in e+e- annihilations, as well as the rapidity shape measured over a large range. The energy dependence of the integrated multiplicity per participant pair shows that e+e- and A+A data agree over a large range of center-of-mass energies (s>20 GeV), and pp/p¯p data can be brought to agree approximately with the e+e- data by correcting for the typical energy taken away by leading particles. This is suggestive of a mechanism for soft particle production that depends mainly on the amount of available energy. It is conjectured that the dominant distinction between A+A and p+p collisions is the multiple collisions per participant, which appears to be sufficient to substantially reduce the energy taken away by leading particles.

  11. Four-body charge transfer processes in collisions of bare projectile ions with helium atoms

    Science.gov (United States)

    Jana, S.; Mandal, C. R.; Purkait, M.

    2015-02-01

    Single-electron capture by a bare ion from a helium atom at intermediate and high energies in the framework of four-body distorted wave (DW-4B) approximation in both prior and post form has been considered. In the entrance channel, the initial bound state wave function is distorted by the incoming projectile ion, and the corresponding distortion is related to the Coulomb continuum states of the active electron and the residual target ion in the field of the projectile ion respectively. Continuum states of the active electron and the projectile ion in the field of the residual target ion are also included in the exit channel. It may be mentioned that the effect of dynamic electron correlation is explicitly taken into account through the complete perturbation potential. The total single-electron capture cross sections are obtained by summing over all contributions up to n = 3 shells and sub-shells respectively. In addition, the differential cross sections for alpha particle-helium collision are calculated at impact energies of 60, 150, 300, 450, and 630 keV amu-1, respectively. The cross sections exhibit a monotonically decreasing angular dependence, with clear peak structures around 0.1 to 0.2 mrad being found at low impact energies. The current theoretical results, both in prior and post forms of the transition amplitude for symmetric and asymmetric collision, are compared with the available theoretical and experimental results. Current computed results have been found to be satisfactory in comparison with other theoretical and experimental findings.

  12. Four-body charge transfer processes in collisions of bare projectile ions with helium atoms

    International Nuclear Information System (INIS)

    Single-electron capture by a bare ion from a helium atom at intermediate and high energies in the framework of four-body distorted wave (DW-4B) approximation in both prior and post form has been considered. In the entrance channel, the initial bound state wave function is distorted by the incoming projectile ion, and the corresponding distortion is related to the Coulomb continuum states of the active electron and the residual target ion in the field of the projectile ion respectively. Continuum states of the active electron and the projectile ion in the field of the residual target ion are also included in the exit channel. It may be mentioned that the effect of dynamic electron correlation is explicitly taken into account through the complete perturbation potential. The total single-electron capture cross sections are obtained by summing over all contributions up to n = 3 shells and sub-shells respectively. In addition, the differential cross sections for alpha particle–helium collision are calculated at impact energies of 60, 150, 300, 450, and 630 keV amu−1, respectively. The cross sections exhibit a monotonically decreasing angular dependence, with clear peak structures around 0.1 to 0.2 mrad being found at low impact energies. The current theoretical results, both in prior and post forms of the transition amplitude for symmetric and asymmetric collision, are compared with the available theoretical and experimental results. Current computed results have been found to be satisfactory in comparison with other theoretical and experimental findings. (paper)

  13. Unfolding of event-by-event net-charge distributions in heavy-ion collisions

    CERN Document Server

    Garg, P; Netrakanti, P K; Mohanty, A K; Mohanty, B

    2013-01-01

    An unfolding method, based on Bayes theorem is presented to obtain true event-by-event net-charge multiplicity distribution from a corresponding measured distribution, which is subjected to detector artifacts. The unfolding is demonstrated to work for widely varying particle production mechanism, beam energy and collision centrality. Further the necessity of taking into account the detector effects is emphasized before comparing the experimental measurements to the theoretical calculations, particularly in case of higher moments. The advantage of this approach being that one need not construct new observable to cancel out detector effects which loose their ability to be connected to physical quantities calculable in standard theories.

  14. Correlation between the fragmentation modes and light charged particles emission in heavy ion collisions

    Institute of Scientific and Technical Information of China (English)

    ZHANG YingXun[1; ZHOU ChengShuang[1,2; CHEN JiXian[1,2; WANG Ning[2; ZHAO Kai[1; LI ZhuXia[1

    2015-01-01

    The correlation between the shape of rapidity distribution of the yield of light charged particles and the fragmentation modes in semi-peripheral collisions for 70Zn+70Zn, 64Zn+64Zn and 64Ni+64Ni at the beam energy of 35 MeV/nucleon is investigated based on ImQMD05 code. Our studies show there is an interplay between the binary, ternary and multi-fragmentation break-up modes. The binary and ternary break-up modes more prefer to emit light charged particles at middle rapidity and give larger values of Rmid compared with the multi-fragmentation break-up mode does. The reduced rapidity distribution for the normalized yields of yield p, d, t, 3He, 4He and 6He and the corresponding values ~ Rmid oI yield can be used to estimate the probability of multi-fragmentation break-up modes. By comparing to experimental data, our results illustrate that ~40% of the collisions events belong to the multi- fragmentation break-up mode for the reactions we studied.

  15. One- and two-electron processes in charge transfer and single ionization in ion-lithium collisions

    International Nuclear Information System (INIS)

    In this work the dynamics of one- and two-electron transitions in ion-lithium collisions is investigated. The measurements are performed with a novel experimental technique (MOTReMi) combining a magneto-optically trapped (MOT) Li target with a Reaction Microscope (ReMi) enabling the momentum resolved and coincident detection of the target fragments. This apparatus was implemented in the ion storage ring TSR providing electron-cooled projectile beams with high currents and low momentum spread. Due to the high resolution and by means of optical excitation, for the first time initial state selective fully differential cross sections for ion-impact induced ionization and charge transfer became available. Transitions of 1s, 2s and 2p target electrons were investigated shedding light on the role of the projectile coherence length, electronic correlation in two-electron transitions and target polarization effects, thereby enhancing our understanding of the few-body problem in quantum dynamics.

  16. A multiply charged ion source for atomic and electronic collision studies

    International Nuclear Information System (INIS)

    An electron cyclotron resonance source has been realized; the principal properties are: good gas efficiency, low gas pressure in the source and in the extraction region; the current density that can be extracted at 12kV is of the order of 240mA/cm2. When working with nitrogen, charge states for the ions up to +5 may be reached: for charge +4, the abundance is about 1%. Another remarkable property is the normalized emittance value at 10kV: 4.5 10-7 m-rad

  17. Grazing incidence collisions of ions and atoms with surfaces: from charge exchange to atomic diffraction

    International Nuclear Information System (INIS)

    This thesis reports two studies about the interaction with insulating surfaces of keV ions or atoms under grazing incidence. The first part presents a study of charge exchange processes occurring during the interaction of singly charged ions with the surface of NaCl. In particular, by measuring the scattered charge fraction and the energy loss in coincidence with electron emission, the neutralization mechanism is determined for S+, C+, Xe+, H+, O+, Kr+, N+, Ar+, F+, Ne+ and He+. These results show the importance of the double electron capture as neutralization process for ions having too much potential energy for resonant capture and not enough for Auger neutralization. We have also studied the ionisation of the projectile and of the surface, and the different Auger-like neutralization processes resulting in electron emission, population of conduction band or excited state. For oxygen scattering, we have measured an higher electron yield in coincidence with scattered negative ion than with scattered atom suggesting the transient formation above the surface of the oxygen doubly negative ion. The second study deals with the fast atom diffraction, a new phenomenon observed for the first time during this work. Due to the large parallel velocity, the surface appears as a corrugated wall where rows interfere. Similarly to the Thermal Atom Scattering the diffraction pattern corresponds to the surface potential and is sensitive to vibrations. We have study the H-NaCl and He-LiF atom-surface potentials in the 20 meV - 1 eV range. This new method offers interesting perspectives for surface characterisation. (author)

  18. Scaling for state-selective charge exchange due to collisions of multicharged ions with hydrogen

    Science.gov (United States)

    Jorge, A.; Illescas, Clara; Miraglia, J. E.; Gravielle, M. S.

    2015-12-01

    In this article we evaluate state-resolved charge exchange cross sections for Be{}4+, {{{B}}}5+, {{{C}}}6+, {{{N}}}7+, and {{{O}}}8+ projectiles colliding with atomic hydrogen employing two different methods: the classical trajectory Monte Carlo and the eikonal impulse approximations. These cross sections are used to extend previously derived scaling laws for n-, nl-, and nlm-distributions to highly excited final levels with 4≤slant n≤slant 9, covering energies in the range 50-2000 {{keV}}/ amu. Present total and partial capture cross sections are in agreement with available experimental and theoretical data for these collision systems. Besides, the proposed scaling rules are also verified by other theories, becoming a useful instrument for plasma research.

  19. Ionization and charge transfer in high-energy ion-atom collisions

    International Nuclear Information System (INIS)

    Electron capture and loss by fast highly charged ions in a gas target, and ionization of the target by passage of the fast projectile beam, are fundamental processes in atomic physics. These processes, along with excitation, can be experimentally studied separately (''singles'') or together (''coincidence''). This paper is a review of recent results on singles measurements for electron capture and loss and for target ionization, for velocities which are generally high relative to the active electron, including recent ionization measurements for a nearly relativistic projectile. 11 refs., 6 figs

  20. X-ray spectra induced by slow highly charged Arq+ ions in collision with Nb surface

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The X-ray spectra of Nb surface induced by Arq+ (q =16,17) ions with the energy range from 10 to 20 keV/q were studied by the optical spectrum technology. The experimental results indicate that the multi-electron excitation occurred as a highly charged Ar16+ ion was neutralized below the metal surface. The K shell electron of Ar16+ was excited and then de-excited cascadly to emit K X-ray. The intensity of the X-ray emitted from K shell of the hollow Ar atom decreased with the increase of projectile kinetic energy. The intensity of the X-ray emitted from L shell of the target atom Nb increased with the increase of projectile kinetic energy. The X-ray yield of Ar17+ is three magnitude orders larger than that of Ar16+.

  1. Surface charging and x-ray emission from insulator surfaces induced by collisions with highly charged ions : relevance to cometary and planetary sp

    Science.gov (United States)

    Djuric, N.; Lozano, J. A.; Smith, S. J.; Chutjian, A.

    2005-01-01

    Characteristic X-ray emission lines are detected from simulants of comet surfaces as they undergo collisions with highly charged ions (HCIs). The HCI projectiles are O+2-O+7. Ion energies are varied in the range (2-7)q keV, where q is the ion charge state. The targets are the insulator minerals olivine, augite, and quartz. It is found that the emission of characteristic K-L, K-M X-rays appears to proceed during positive charging of the surface by the HCI beam. When one uses low-energy, flood-gun electrons to neutralize the surface charge, the X-ray emission is eliminated or greatly reduced, depending on the flood-gun current. Acceleration of background electrons onto the charged surface results in excitation of elemental transitions, including the K-L2 and K-L3 target X-ray emission lines of Mg and Si located spectroscopically at 1253.6 and 1739.4 eV, respectively. Also observed are emission lines from O, Na, Ca, Al, and Fe atoms in the target and charge-exchange lines via surface extraction of electrons by the O+q electric field. Good agreement is found in the ratio of the measured X-ray yields for Mg and Si relative to the ratio of their electron-impact K-shell ionization cross sections. The present study may serve as a guide to astronomers as to specific observing X-ray energies indicative of solar/stellar wind or magnetospheric ion interactions with a comet, planetary surface, or circumstellar dust.

  2. Charged particle yields and spectra in p+p and Heavy Ion Collisions with ATLAS at the LHC

    CERN Document Server

    Dolejší, J; The ATLAS collaboration

    2010-01-01

    The ATLAS experiment has extensive charged particle tracking over full azimuth and within |eta|<2.5. The spectrometer consists of three pixel layers and four double-layer strip layers, giving 11 space points in all. The existing tracking software used for proton-proton collisions has been optimized for the high-multiplicity heavy ion environment. Extensions of the existing tracking to lower pT (100 MeV) using tracks and pixel tracklets, work underway for p+p, will be discussed in the context of heavy ion collisions. Finally, by correlating high momentum tracks with the ATLAS calorimetry, fake tracks can also be rejected at very high pT. The physics performance of the ATLAS inner detector for dN/deta, inclusive particle spectra, and two-particle correlations (in delta-eta and delta-phi) will be discussed. The tracking performance within jets, which is essential for the measurement of jet fragmentation functions, will also be presented.

  3. Correlated charge changing ion-atom collisions: Progress report for the period August 15, 1984-February 14, 1987

    International Nuclear Information System (INIS)

    Correlations between x-ray emission and charge-changing interactions have been measured for high charged ions (16 ≤ Z ≤ 23) in the energy range of 0.1 to 10 MeV/u incident on gas targets under single collision conditions. These experiments combined with theoretical studies have established the existence of resonant transfer and excitation (RTE) and indicated a close relationship between RTE and dielectronic recombination. Detailed investigations of RTE include: (1) the projectile Z dependence; (2) the projectile charge-state dependence; (3) the effect of the target electron momentum distribution; and (4) observations of RTE involving L-shell excitation. These measurements are in reasonable agreement with theoretical calculations. Evidence for non-resonant transfer and excitation has been obtained from studies of 15 to 200 MeV S13+ + He collisions. Single-electron capture and loss were measured for 2.5 to 200 MeV S13+ + He thereby providing a comparison with theory over a very wide energy range. For single capture in Ca/sup 16,17,18,19+ + H2 a significant contribution due to RTE was observed for energies where RTE is important. Cross sections for double-electron capture for S13+ + He and Ne and Ar15+ + Ne were found to be 1 to 2 orders of magnitude smaller than the corresponding single-capture cross sections. Target ionization associated with projectile charge exchange has been measured for 0.5 to 1.5 MeV/u O/sup 5,6,7,8+ + He and H2. 26 refs., 13 figs

  4. Electron transfer processes in collisions of highly charged energetic (0. 1 to 1. 0 MeV/nucleon) ions with helium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Datz, S.; Hippler, R.; Andersen, L.H.; Dittner, P.F.; Knudsen, H.; Krause, H.F.; Miller, P.D.; Pepmiller, P.L.; Rosseel, T.; Stolterfoht, N.

    1987-01-01

    We have investigated charge transfer in collisions of energetic (0.1 - 1 MeV/nucleon) highly charged ions with helium atoms with the principal aim clarifying the nature of two-electron processes. The sensitivity of partial charge-changing cross sections (i.e., single- and double-charge transfer, transfer ionization (TI), and single and double ionization) to core configuration and scaling rules for one- and two-electron processes were investigated with iodine ions (q = 5+ ..-->.. 26+) and uranium ions (q = 17+ ..-->.. 44+) using an ion-charge state, recoil-ion coincidence method. Using zero-degree electron spectroscopy in coincidence with charge transfer, we found that at the higher energies, as in the case of 0.1 MeV/nucleon ions previously reported, TI involves the transfer of two electrons to a higher correlated state followed by loss of one electron to the continuum. In addition, we observe very high Rydberg electrons in coincidence with TI, implying a possible up-down correlation in the pair transfer. In addition, we made measurements of VUV photons emitted at the collision in coincidence with He/sup +/ and He/sup 2 +/ recoils. The results show that TI leads to capture into lower n states than single-charge transfer. 15 refs., 10 figs.

  5. Correlated charge changing ion-atom collisions: Progress report for the period February 15, 1987-March 14, 1988

    International Nuclear Information System (INIS)

    This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant DE-FG02-87ER13778 for a period of 13 months from February 15, 1987 through March 14, 1988. The general scope of this work involves the experimental investigation of fundamental atomic interactions in collisions of highly charged projectiles with neutral targets, with a particular emphasis on two-electron interactions. Inner-shell processes involving excitation, ionization, and charge transfer are investigated using coincidence techniques in which projectile charge-changing events are associated with x-ray emission, target recoil ions, or electron emission. New measurements were conducted using accelerators at the Lawrence Berkeley Laboratory, Argonne National Laboratory, Hahn-Meitner-Institut (Berlin), and Western Michigan University. The work at Hahn-Meitner resulted from a collaboration initiated while J. A. T. was on research leave from Western Michigan University during the 1986-1987 academic year. The principal new results obtained during the past year using each of the three coincidence techniques are summarized below. A major emphasis of all these investigations is to determine the role of electron correlation in two- (and multiple-) electron interactions

  6. The Kansas State atomic collision physics facility dedicated to the studies of atomic interactions of highly charged, low and medium energy ions

    International Nuclear Information System (INIS)

    We discuss our facility at Kansas State University, which is perfectly suited for studies of atomic collisions involving highly charged, low and medium energy ions. It should be fully operational by next year and will be operated as a user facility. We encourage collaborations with in-house researchers, because it facilitates communications and experiments. 13 refs., 3 figs

  7. Charge transfer processes of low charge state heavy ions

    International Nuclear Information System (INIS)

    In this paper, some aspects of the collision processes of accelerated heavy ions in very low charge state is reviewed, and the beam loss due to such collisions is estimated. The processes included in ion-atom collisions are electron capture, the electron stripping of ions, and target ionization. The stripping cross sections decrease slowly at high energy, and are much larger than the electron capture cross sections. At low energy, the electron capture is dominant, and this process plays a principal role near ion sources and preacceleration regions. This has not been taken into account properly. In order to keep the beam loss less than 0.1 percent, it is estimated that the average vacuum of about 10-7 to 10-8 Torr is required. An empirical formula to calculate the stripping cross sections of heavy ions in low charge state in collisions is derived. The beam loss due to ion-atom collisions can be estimated. The charge transfer and stripping processes in ion-ion collisions are also discussed. The typical processes in ion-ion collisions are almost same as those in ion-atom collisions. In order to minimize the ion beam loss due to charge-changing processes, it is important to choose the heavy ions with closed shell configurations, which correspond to the slightly more ionized states than the singly ionized state. (Kato, T.)

  8. Isospin Effect of Charged Particle Multiplicity in Intermediate Energy Heavy Ion Collisions

    Institute of Scientific and Technical Information of China (English)

    HuRongjiang; WuHeyu; JinGenming; ZhuYongtai; DuanLimin; XiaoZhigang; WangHongwei

    2003-01-01

    The dependences of He and intermediate mass fragments (IMF) production rates in the reactions 55 MeV/u 40Ar+58,64 Ni on the isospin, impact parameter and primary excitation energy of the reaction nuclear system were studied by using the 4π charged particle multi-detector array system (MUDAL). For the mentioned two reaction systems, the measured He particle contribution in the total charged particle multiplicity increases with increasing the total charged particle multiplicity but for the contribution of IMFs in the total charged particle multiplicity increases with increasing the total charged particle multiplicity at lower total charged particle multiplicities, and latter on it drops down with further increasing of the total charged particle multiplicities (see Fig.l). The experimental results of these two reaction systems with the same nuclear charge indicate that the contribution of He and IMFs in the total charged particle multiplicities are obviously isospin dependent.

  9. L X-ray emission from fast highly charged Cu ions in collisions with gaseous targets: Saturation effect in excitation and transfer

    Science.gov (United States)

    Kumar, Ajay; Misra, D.; Kadhane, U.; Kelkar, A. H.; Dhal, B. B.; Tribedi, L. C.

    2006-11-01

    We have measured L X-ray production cross sections for highly charged 156 MeV Be-like Cu ions in collisions with gaseous targets of H 2, Ne, Ar, Kr and Xe. In the present collision systems, measured projectile L X-ray intensity is contributed by the excitation as well as electron transfer processes. The projectile L X-ray production cross sections are found to increase initially and then saturate with increasing target atomic number. The charge state dependence of projectile L X-ray production cross sections have been measured with Kr target.

  10. Atomic collision studies at moderate projectile velocities using highly charged, decelerated heavy ions from the GSI-UNILAC

    International Nuclear Information System (INIS)

    Beams of highly ionized, very heavy atoms at moderate velocities have been produced at the UNILAC using the acceleration-stripping-deceleration method. The available ion species range from Kr33+ to U66+ in the energy region between 2 and 5 MeV/u. A survey on first experiments at GSI using these moderate velocity, few electron, heavy ion beams is given. The effectiveness of the method is demonstrated for Xesup(q+)-Xe collision experiments with 41 <= q <= 45. Results on vacancy transfer between inner quasimolecular levels for close collisions, and on distant collision electron capture are reported. (orig.)

  11. State-diagnosed charge stripping in low-energy collisions of ground-state and highly excited N+ ions with He

    International Nuclear Information System (INIS)

    Translational energy spectra have been measured on N2+ product ions resulting from 2-keV charge-stripping collisions between N+ ions and He. The projectile N+ ion beam is produced under varying ion source conditions so as to contain different fractions of a long-lived metastable component. By measuring the endoergic energy defect for charge stripping from ground-state and excited-state projectiles at different electron energies in the ion source, the quantal identity of the N+ metastable state is deduced to be either 2s2p22p' 1D0, which lies 17.9 eV above the 2s22p23P ground electronic state, or 2s22p3s 1P0, whose excitation energy is 18.5 eV

  12. Charge-changing reactions of secondary fragments produced in high-energy heavy ion collisions

    International Nuclear Information System (INIS)

    The authors have begun a program to measure charge changing cross sections of projectile fragments using a quite different technique that is capable of much higher data acquisition rates. The primary beam impinges on a stack of 50 Lucite strips having an average thickness of 3.17 mm, emitting Cerenkov light as its passes through them. Since at a given velocity the intensity of light is proportional to Z2, where Z is the charge of the particle, a fragmentation reaction in a particular strip will be registered as a drop in the light output from that and subsequent strips. The authors use total internal reflection to transport the light to photomultiplier tubes so that there is no wrapping between the strips. Since the energy threshold of the device is approx.1.1 GeV/nucleon, low energy target fragments will not contribute to the signal, a distinct advantage over similar schemes using energy loss to measure the fragment charge. The resolution of the individual strips is typically 0.58 charge units, full width at half maximum, allowing reactions to be well localized even for single unit charge changes. In addition to the C detectors, scintillators and Si(Li) detectors were used to measure precisely the position and charge of the incoming beam particle. The authors have taken data using two beams, 56Fe and 40Ar, at 1.88 and 1.82 GeV/nucleon respectively, and two trigger modes, a free trigger to measure the reaction rate of the incoming beam and an inelastic trigger in which a reaction was required to occur in one of the first 14 C detectors. A total of 909,000 56Fe interactions and 460,000 40Ar interactions have been analyzed so far

  13. NA49: lead ion collision

    CERN Multimedia

    1995-01-01

    This is an image of an actual lead ion collision taken from tracking detectors on the NA49 experiment, part of the heavy ion project at CERN. These collisions produce a very complicated array of hadrons as the heavy ions break up. It is hoped that one of these collisions will eventually create a new state of matter known as quark-gluon plasma.

  14. NA49: lead ion collision

    CERN Multimedia

    1995-01-01

    This is an image of an actual lead ion collision taken from the NA49 experiment, part of the heavy ion project at CERN. These collisions produce a very complicated array of hadrons as the heavy ions break up. It is hoped that one of these collisions will eventually create a new state of matter known as the quark-gluon plasma.

  15. Study of charged pions elliptic flow in heavy ion collisions at 62.4 GeV

    International Nuclear Information System (INIS)

    Heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) produce strongly interacting matter under extreme conditions of temperature and energy density, similar to those prevailing in the first few microseconds after the Big Bang. The quark-gluon plasma (QGP) is a state of matter whose existence at high energy density is predicted by Quantum Chromodynamics. The creation of this state of matter in the laboratory, and the study of its properties are the main goals of the ultra-relativistic nuclear collision program. In this work we studied variation of elliptic flow of particles π+ and π- with mean multiplicity at centre of mass energy 62.4 GeV. We also varied the collision species e.g. Au+Au and Cu+Cu

  16. Parton Energy Loss in Heavy-Ion Collisions via Direct-Photon and Charged-Particle Azimuthal Correlations

    OpenAIRE

    Abelev, B. I.; Benedosso, F.; Braidot, E.; Mischke, A.; Peitzmann, T.(Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands); Russcher, M. J.

    2010-01-01

    Charged-particle spectra associated with direct photon ($\\gamma_{dir} $) and $\\pi^0$ are measured in $p$+$p$ and Au+Au collisions at center-of-mass energy $\\sqrt{s_{_{NN}}}=200$ GeV with the STAR detector at RHIC. A hower-shape analysis is used to partially discriminate between $\\gamma_{dir}$ and $\\pi^0$. Assuming no associated charged particles in the $\\gamma_{dir}$ direction (near side) and small contribution from fragmentation photons ($\\gamma_{frag}$), the associated charged-particle yiel...

  17. Excitation of atoms and molecules in collisions with fast, highly charged ions: Progress report for the period January 1, 1988 to February 28, 1989

    International Nuclear Information System (INIS)

    This report summarizes progress in research supported by DOE Grant FG05-84ER13262 during the period January 1, 1988 to February 29, 1989. The research program continues to emphasize the investigation of multielectron ionization and capture processes in fast heavy-ion collisions. Several major projects were completed this year and a number of new ones begun. Among the completed projects were an investigation of resonant multielectron transfer to double K-vacancy states in solid oxygen compounds, and a study of collisional quenching of 23P and 24P states in 33 MeV two- and three-electron Mg ions. New projects include a systematic investigation of the projectile charge dependence of cross sections for Ar recoil-ion production in 1 MeV/amu oxygen ion collisions production, and a design study for an atomic physics beam line to be connected to an electron-cyclotron-resonance (ECR) ion source. Work on molecular fragmentation in heavy-ion collisions continued

  18. Phenomenological approaches of dissipative heavy ion collisions

    International Nuclear Information System (INIS)

    These lectures describe the properties of dissipative heavy ion collisions observed in low bombarding energy heavy ion reactions. These dissipative collisions are of two different types: fusion and deep inelastic reactions. Their main experimental properties are described on selected examples. It is shown how it is possible to give a simple interpretation to the data. A large number of phenomenological models have been developped to understand dissipative heavy ion collisions. The most important are those describing the collision by classical mechanics and friction forces, the diffusion models, and transport theories which merge both preceding approaches. A special emphasis has been done on two phenomena observed in dissipative heavy ion collisions: charge equilibratium for which we can show the existence of quantum fluctuations, and fast fission which appears as an intermediate mechanism between deep inelastic reactions and compound nucleus formation

  19. Charge exchange transition probability for collisions between unlike ions and atoms within the adiabatic approximation

    Science.gov (United States)

    Xu, Y. J.; Khandelwal, G. S.; Wilson, John W.

    1989-01-01

    A simple formula for the transition probability for electron exchange between unlike ions and atoms is established within the adiabatic approximation by employing the Linear Combination of Atomic Orbitals (LCAO) method. The formula also involves an adiabatic parameter, introduced by Massey, and thus the difficulties arising from the internal energy defect and the adiabatic approximation are avoided. Specific reactions Li(+++) + H to Li(++) + H(+) and Be(4+) + H to Be(3+) + H(+) are considered as examples. The calculated capture cross section results of the present work are compared with the experimental data and with the calculation of other authors over the velocity range of 10(7) cm/sec to 10(8) cm/sec.

  20. Extended Classical Over-Barrier Model for Collisions of Highly Charged Ions with Conducting and Insulating Surfaces

    OpenAIRE

    Ducree, Jens J.; Casali, Fulvio; Thumm, Uwe

    1997-01-01

    We have extended the classical over-barrier model to simulate the neutralization dynamics of highly charged ions interacting under grazing incidence with conducting and insulating surfaces. Our calculations are based on simple model rates for resonant and Auger transitions. We include effects caused by the dielectric response of the target and, for insulators, localized surface charges. Characteristic deviations regarding the charge transfer processes from conducting and insulating targets to...

  1. Final state effects on charge asymmetry of pion elliptic flow in high-energy heavy-ion collisions

    CERN Document Server

    Ma, Guo-Liang

    2014-01-01

    Within a multi-phase transport (AMPT) model with string melting mechanism and an imported electric charge quadrupole distribution in the initial partonic coordinate space, the elliptic flow asymmetry between positive and negative pions is investigated. The slope parameter $r$ of the linear dependence of $\\Delta v_{2}=v_{2}(\\pi^{-})-v_{2}(\\pi^{+})$ on $A_{ch}=(N^{+}-N^{-})/(N^{+}+N^{-})$ is yielded by the conversion from an initial electric charge quadrupole distribution to a charge-dependent elliptic flow via a strong parton cascade process. The slope parameter $r$ is increased by the hadronization of coalescence, and then decreased by final resonance decays. Because the slope parameter $r$ is very sensitive to both initial electric charge quadrupole percentage and centrality, a helpful constraint of the effect from chiral magnetic wave is extracted out in Au+Au collisions at the top RHIC energy.

  2. Charge breeding investigation in EBIS/T and collision study of ions with cold atoms for HITRAP

    OpenAIRE

    Sokolov, Alexey

    2010-01-01

    Highly charged ions (HCI) at low velocities or at rest are interesting systems for various atomic physics experiments. For investigations on HCI of heavy stable or radioactive nuclides the HITRAP (Highly charged Ion TRAP) decelerator facility has been set up at GSI to deliver cooled beams of HCI at an energy of 5 keV/q. The HCI are produced in a stripper foil at relativistic energies and are decelerated in several steps at ESR storage ring and HITRAP before they are delivered to experimental ...

  3. Collision-induced dissociation of fatty acid [M - 2H + Na]- ions: charge-directed fragmentation and assignment of double bond position.

    Science.gov (United States)

    Thomas, Michael C; Altvater, Jens; Gallagher, Thomas J; Nette, Geoffrey W

    2014-11-01

    The collision-induced dissociation (CID) of cationic fatty acid-metal ion complexes has been extensively studied and, in general, provides rich structural information. In particular, charge-remote fragmentation processes are commonly observed allowing the assignment of double bond position. In a previous manuscript, we presented two methods to doubly deprotonate polyunsaturated fatty acids to form anionic fatty acid-sodium ion complexes, referred to as [M - 2H + Na] (-) ions. In the current manuscript, the CID behavior of these [M - 2H + Na] (-) ions is investigated for the first time. Significantly, we also present a deuterium-labeling experiment, which excludes the possibility that deprotonation occurs predominately at the α-carbon in the formation of fatty acid [M - H + NaF](-) ions. This supports our original proposal where deprotonation occurs at the bis-allylic positions of polyunsaturated fatty acids. CID spectra of polyunsaturated fatty acid [M - 2H + Na](-) ions display abundant product ions arising from acyl chain cleavages. Through the examination of fatty acid isomers, it is demonstrated that double bond position may be unequivocally determined for methylene-interrupted polyunsaturated fatty acids with three or more carbon-carbon double bonds. In addition, CID of [M - 2H + Na](-) ions was applied to 18:3 isomers of Nannochloropsis oculata and three isomers were tentatively identified: ∆(9,12,15)18:3, ∆(6,9,12)18:3, and ∆(5,8,11)18:3. We propose that structurally-informative product ions are formed via charge-driven fragmentation processes at the site of the resonance-stabilized carbanion as opposed to charge-remote fragmentation processes, which could be inferred if deprotonation occurred predominately at the α-carbon. PMID:25142324

  4. Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions

    CERN Document Server

    Adamczyk, L; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Bairathi,; Banerjee, A; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Bouchet, J; Brandin, A V; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Sánchez, M Calderón de la Barca; Campbell, J M; Cebra, D; Cervantes, M C; Chakaberia, I; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, J H; Chen, X; Cheng, J; Cherney, M; Christie, W; Contin, G; Crawford, H J; Das, S; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; di Ruzza, B; Didenko, L; Dilks, C; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Eppley, G; Esha, R; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, Z; Filip, P; Fisyak, Y; Flores, C E; Fulek, L; Gagliardi, C A; Garand, D; Geurts, F; Gibson, A; Girard, M; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Hamad, A; Hamed, A; Haque, R; Harris, J W; He, L; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, X; Huang, H Z; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Jiang, K; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Kochenda, L; Koetke, D D; Kollegger, T; Kosarzewski, L K; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Li, W; Li, Z M; Li, X; Li, Y; Li, C; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, Y G; Ma, R; Ma, G L; Ma, L; Magdy, N; Majka, R; Manion, A; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; Meehan, K; Minaev, N G; Mioduszewski, S; Mishra, D; Mohanty, B; Mondal, M M; Morozov, D; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Okorokov, V; Olvitt, D; Page, B S; Pak, R; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlik, B; Pei, H; Perkins, C; Peterson, A; Pile, P; Planinic, M; Pluta, J; Poljak, N; Poniatowska, K; Porter, J; Posik, M; Poskanzer, A M; Pruthi, N K; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, M K; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Sikora, R; Simko, M; Skoby, M J; Smirnov, N; Smirnov, D; Song, L; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stepanov, M; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Summa, B; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, N; Szelezniak, M A; Tang, Z; Tang, A H; Tarnowsky, T; Tawfik, A N; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Tripathy, S K; Trzeciak, B A; Tsai, O D; Ullrich, T; Underwood, D G; Upsal, I; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Varma, R; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Vossen, A; Wang, G; Wang, H; Wang, J S; Wang, Y; Wang, F; Webb, G; Webb, J C; Wen, L; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z G; Xie, W; Xin, K; Xu, Q H; Xu, N; Xu, H; Xu, Z; Xu, Y F; Yang, Q; Yang, Y; Yang, C; Yang, S; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I -K; Yu, N; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J; Zhang, X P; Zhang, Z; Zhang, Y; Zhang, S; Zhao, J; Zhong, C; Zhou, L; Zhu, X; Zoulkarneeva, Y; Zyzak, M

    2015-01-01

    We present measurements of $\\pi^-$ and $\\pi^+$ elliptic flow, $v_2$, at midrapidity in Au+Au collisions at $\\sqrt{s_{_{\\rm NN}}} =$ 200, 62.4, 39, 27, 19.6, 11.5 and 7.7 GeV, as a function of event-by-event charge asymmetry, $A_{ch}$, based on data from the STAR experiment at RHIC. We find that $\\pi^-$ ($\\pi^+$) elliptic flow linearly increases (decreases) with charge asymmetry for most centrality bins at $\\sqrt{s_{_{\\rm NN}}} = \\text{27 GeV}$ and higher. At $\\sqrt{s_{_{\\rm NN}}} = \\text{200 GeV}$, the slope of the difference of $v_2$ between $\\pi^-$ and $\\pi^+$ as a function of $A_{ch}$ exhibits a centrality dependence, which is qualitatively similar to calculations that incorporate a chiral magnetic wave effect. Similar centrality dependence is also observed at lower energies.

  5. Application of the Landau-Zener model and the classical trajectory Monte Carlo method for capture processes in collisions of highly charged ions with light atoms

    International Nuclear Information System (INIS)

    In describing the collision dynamics of processes SEC and DEC (single and double electron capture, respectively) in case of the He target the one active electron approximation was used with a single-centre effective potential for calculations of the dominant (n,l)-level state selective and total charge exchange cross sections. For He target part of the diexcited states of the projectile ions produced by DEC decay by Auger emission of one electron. This autoionizing double capture channel (ADEC) is not taken into account in the present work. (R.P.)

  6. Grazing incidence collisions of ions and atoms with surfaces: from charge exchange to atomic diffraction; Collisions rasantes d'ions ou d'atomes sur les surfaces: de l'echange de charge a la diffraction atomique

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, P

    2006-09-15

    This thesis reports two studies about the interaction with insulating surfaces of keV ions or atoms under grazing incidence. The first part presents a study of charge exchange processes occurring during the interaction of singly charged ions with the surface of NaCl. In particular, by measuring the scattered charge fraction and the energy loss in coincidence with electron emission, the neutralization mechanism is determined for S{sup +}, C{sup +}, Xe{sup +}, H{sup +}, O{sup +}, Kr{sup +}, N{sup +}, Ar{sup +}, F{sup +}, Ne{sup +} and He{sup +}. These results show the importance of the double electron capture as neutralization process for ions having too much potential energy for resonant capture and not enough for Auger neutralization. We have also studied the ionisation of the projectile and of the surface, and the different Auger-like neutralization processes resulting in electron emission, population of conduction band or excited state. For oxygen scattering, we have measured an higher electron yield in coincidence with scattered negative ion than with scattered atom suggesting the transient formation above the surface of the oxygen doubly negative ion. The second study deals with the fast atom diffraction, a new phenomenon observed for the first time during this work. Due to the large parallel velocity, the surface appears as a corrugated wall where rows interfere. Similarly to the Thermal Atom Scattering the diffraction pattern corresponds to the surface potential and is sensitive to vibrations. We have study the H-NaCl and He-LiF atom-surface potentials in the 20 meV - 1 eV range. This new method offers interesting perspectives for surface characterisation. (author)

  7. Comparative study on contribution of charge-transfer collision to excitations of iron ion between argon radio-frequency inductively-coupled plasma and nitrogen microwave induced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Kozue; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2015-06-01

    This paper describes an ionization/excitation phenomenon of singly-ionized iron occurring in an Okamoto-cavity microwave induced plasma (MIP) as well as an argon radio-frequency inductively-coupled plasma (ICP), by comparing the Boltzmann distribution among iron ionic lines (Fe II) having a wide range of the excitation energy from 4.76 to 9.01 eV. It indicated in both the plasmas that plots of Fe II lines having lower excitation energies (4.76 to 5.88 eV) were fitted on each linear relationship, implying that their excitations were caused by a dominant thermal process such as collision with energetic electron. However, Fe II lines having higher excitation energies (more than 7.55 eV) had a different behavior from each other. In the ICP, Boltzmann plots of Fe II lines assigned to the higher excited levels also followed the normal Boltzmann relationship among the low-lying excited levels, even including a deviation from it in particular excited levels having an excitation energy of ca. 7.8 eV. This deviation can be attributed to a charge-transfer collision with argon ion, which results in the overpopulation of these excited levels, but the contribution is small. On the other hand, the distribution of the high-lying excited levels was non-thermal in the Okamoto-cavity MIP, which did not follow the normal Boltzmann relationship among the low-lying excited levels. A probable reason for the non-thermal characteristics in the MIP is that a charge-transfer collision with nitrogen molecule ion having many vibrational/rotational levels could work for populating the 3d{sup 6}4p (3d{sup 5}4s4p) excited levels of iron ion broadly over an energy range of 7.6–9.0 eV, while collisional excitation by energetic electron would occur insufficiently to excite these high-energy levels. - Highlights: • This paper describes the excitation mechanism of iron ion in Okamoto-cavity MIP in comparison with conventional ICP. • Boltzmann distribution is studied among iron ionic lines of

  8. Comparative study on contribution of charge-transfer collision to excitations of iron ion between argon radio-frequency inductively-coupled plasma and nitrogen microwave induced plasma

    International Nuclear Information System (INIS)

    This paper describes an ionization/excitation phenomenon of singly-ionized iron occurring in an Okamoto-cavity microwave induced plasma (MIP) as well as an argon radio-frequency inductively-coupled plasma (ICP), by comparing the Boltzmann distribution among iron ionic lines (Fe II) having a wide range of the excitation energy from 4.76 to 9.01 eV. It indicated in both the plasmas that plots of Fe II lines having lower excitation energies (4.76 to 5.88 eV) were fitted on each linear relationship, implying that their excitations were caused by a dominant thermal process such as collision with energetic electron. However, Fe II lines having higher excitation energies (more than 7.55 eV) had a different behavior from each other. In the ICP, Boltzmann plots of Fe II lines assigned to the higher excited levels also followed the normal Boltzmann relationship among the low-lying excited levels, even including a deviation from it in particular excited levels having an excitation energy of ca. 7.8 eV. This deviation can be attributed to a charge-transfer collision with argon ion, which results in the overpopulation of these excited levels, but the contribution is small. On the other hand, the distribution of the high-lying excited levels was non-thermal in the Okamoto-cavity MIP, which did not follow the normal Boltzmann relationship among the low-lying excited levels. A probable reason for the non-thermal characteristics in the MIP is that a charge-transfer collision with nitrogen molecule ion having many vibrational/rotational levels could work for populating the 3d64p (3d54s4p) excited levels of iron ion broadly over an energy range of 7.6–9.0 eV, while collisional excitation by energetic electron would occur insufficiently to excite these high-energy levels. - Highlights: • This paper describes the excitation mechanism of iron ion in Okamoto-cavity MIP in comparison with conventional ICP. • Boltzmann distribution is studied among iron ionic lines of various

  9. Intermediate energies heavy ion collisions : study of the charged particles emission dynamics and emitters characterization; Collisions d`ions lourds aux energies intermediaires: etude de la dynamique d`emission des particules chargees et caracterisation des emetteurs

    Energy Technology Data Exchange (ETDEWEB)

    Bauge, E.

    1994-07-01

    In heavy ion collisions at intermediate energies, reaction processes are ranging from slow processes where equilibrium is achieved between every emission, up to direct processes where nucleon nucleon scattering and phase space availability are the deciding factors. In order to investigate this transition, both the emission dynamics and the characteristics of the emitter have been studied, both theoretically and experimentally in the AMPHORA detector, for the systems 7, 17, 27 and 34 AMeV, {sup 40}Ar+Al, {sup 40}Ar+Cu and {sup 40}Ar+Ag. First, the linear momentum transfer of the most central collisions has been evaluated for these systems, by measuring the velocity of heavy residues. Then, by measuring azimuthal angle correlations functions, and by comparing them with statistical model predictions, the average angular momentum of the emitter has been evaluated. To study the charged particles emission dynamics, experimental azimuthal angle and relative momentum correlation functions have been compared with simulations based on a classical trajectory model. Finally, predictions of an advanced BUU model have been studied for the system 34 AMeV 40 Ar+Al. (authors). 69 refs., 52 figs., 5 tabs.

  10. Collision induced dissociation of doubly-charged ions: Coulomb explosion vs. neutral loss in [Ca(urea)]2+ gas phase unimolecular reactivity via chemical dynamics simulations

    International Nuclear Information System (INIS)

    In this paper we report different theoretical approaches to study the gas-phase unimolecular dissociation of the doubly-charged cation [Ca(urea)]2+, in order to rationalize recent experimental findings. Quantum mechanical plus molecular mechanical (QM/MM) direct chemical dynamics simulations were used to investigate collision induced dissociation (CID) and rotational-vibrational energy transfer for Ar+ [Ca(urea)]2+ collisions. For the picosecond time-domain of the simulations, both neutral loss and Coulomb explosion reactions were found and the differences in their mechanisms elucidated. The loss of neutral urea subsequent to collision with Ar occurs via a shattering mechanism, while the formation of two singly-charged cations follows statistical (or almost statistical) dynamics. Vibrational-rotational energy transfer efficiencies obtained for trajectories that do not dissociate during the trajectory integration were used in conjunction with RRKM rate constants to approximate dissociation pathways assuming complete intramolecular vibrational energy redistribution (IVR) and statistical dynamics. This statistical limit predicts, as expected, that at long time the most stable species on the potential energy surface (PES) dominate. These results, coupled with experimental CID from which both neutral loss and Coulomb explosion products were obtained, show that the gas phase dissociation of this ion occurs by multiple mechanisms leading to different products and that reactivity on the complicated PES is dynamically complex. (authors)

  11. Atomic-orbital close-coupling calculations of charge exchange and ionisation in collisions of H(1s) and highly charged neon and argon ions

    International Nuclear Information System (INIS)

    Atomic-orbital close-coupling calculations of neon and argon ions colliding with H(1s) will be presented. The high principal quantum numbers n that need to be included in the expansion of the wavefunction of the active electron in the ion center make very large basis sets necessary. The resulting state resolved charge exchange and ionisation cross sections are of special interest for nuclear fusion research.

  12. Highly Charged Ion Sources

    International Nuclear Information System (INIS)

    In this work a study is made for the factors affecting the production and extraction of highly charged ion beams. Discussion is made for the production of highly charged ions from: the conventional vacuum are ion sources (Pinning PIG and Duoplasmatron DP) and the recent trends type which are (Electron Beam Ion Sources EBIS, Electron Cyclotron Resonance Ion Sources ECRIS and Laser Ion source LIS). The highly charged ions with charge state +7 , O+8 ,Ne+10 , Ar+18 have been extracted from the ECRIS while fully stripped Xe+54 has been extracted from EBIS. Improving the capabilities of the conventional RF ion source to produce multiply charged ions is achieved through the use of electron injection into the plasma or with the use of RF driven ion source. The later is based on coupling the RF power to the discharge through an internal antenna in vacuum are ion source. The argon ion species extracted from these upgraded RF ion sources could reach Ar+5

  13. Comparative study on contribution of charge-transfer collision to excitations of iron ion between argon radio-frequency inductively-coupled plasma and nitrogen microwave induced plasma

    Science.gov (United States)

    Satoh, Kozue; Wagatsuma, Kazuaki

    2015-06-01

    This paper describes an ionization/excitation phenomenon of singly-ionized iron occurring in an Okamoto-cavity microwave induced plasma (MIP) as well as an argon radio-frequency inductively-coupled plasma (ICP), by comparing the Boltzmann distribution among iron ionic lines (Fe II) having a wide range of the excitation energy from 4.76 to 9.01 eV. It indicated in both the plasmas that plots of Fe II lines having lower excitation energies (4.76 to 5.88 eV) were fitted on each linear relationship, implying that their excitations were caused by a dominant thermal process such as collision with energetic electron. However, Fe II lines having higher excitation energies (more than 7.55 eV) had a different behavior from each other. In the ICP, Boltzmann plots of Fe II lines assigned to the higher excited levels also followed the normal Boltzmann relationship among the low-lying excited levels, even including a deviation from it in particular excited levels having an excitation energy of ca. 7.8 eV. This deviation can be attributed to a charge-transfer collision with argon ion, which results in the overpopulation of these excited levels, but the contribution is small. On the other hand, the distribution of the high-lying excited levels was non-thermal in the Okamoto-cavity MIP, which did not follow the normal Boltzmann relationship among the low-lying excited levels. A probable reason for the non-thermal characteristics in the MIP is that a charge-transfer collision with nitrogen molecule ion having many vibrational/rotational levels could work for populating the 3d64p (3d54s4p) excited levels of iron ion broadly over an energy range of 7.6-9.0 eV, while collisional excitation by energetic electron would occur insufficiently to excite these high-energy levels.

  14. Final state effects on charge asymmetry of pion elliptic flow in high-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Within a multi-phase transport (AMPT) model with the string melting mechanism and imported initial electric quadrupole moment, the difference between the elliptic flow of positive and negative pions is calculated. The slope parameter r of the linear dependence of Δv2=v2(π−)−v2(π+) on Ach=(N+−N−)/(N++N−) is yielded owing to the parton cascade, which converts the initial electric quadrupole distribution into the final charge-dependent elliptic flow. The slope parameter r is found to be increased by the hadronization given by the coalescence, and decreased by the resonance decays. The slope parameter r is very sensitive to both the initial electric quadrupole percentage and centrality bin and consequently a helpful constraint on the quadrupole moment of the chiral magnetic wave is obtained for Au + Au collisions at the top RHIC energy

  15. Study of elementary transfer mechanisms during a collision between a swift multi-charged heavy ion and a neutral atom

    International Nuclear Information System (INIS)

    This work is dedicated to the study of the energy transfer mechanisms which occur during a collision between a swift multicharged heavy ion and a neutral atom. The elementary energy energy transfer mechanisms (scattering, excitation, ionization, capture) and their consequences on the target velocity after the collision (recoil velocity) are recalled in the first chapter. In the case of small projectile diffusion angles, we show that the recoil velocity component, transverse to the incident projectile direction, results principally from the diffusion mechanism, while the longitudinal component is due essentially to the mass transfer and the inelastic energy transfer mechanisms. Since the target recoil velocities are very small, we have built an experimental set-up which reduces the impreciseness on their measurement due to the target thermal spread using, as targets, cooled atoms of a supersonic jet (temperature 44+(6.7 MeV/A) + Ar => Xe44 + Arq++qe- (q ranging from 1 to 7); Xe44+ (6.7 MeV/A) + He => Xe44+ He1+,2++1e-,2e-. We show that it is possible to interpret the recoil velocity in terms of kinetic energy transferred to the target and to the electrons ejected from the target. (author)

  16. Analysis of charge transfer mechanisms in grazing incidence collisions between He sup + (1s) ions and Al(1 1 1) surfaces

    CERN Document Server

    Gutíerrez, F A; Jequier, S; Jouin, H

    2003-01-01

    We analyze angular distributions of neutralized particles after grazing incidence collisions between slow He sup + (1s) ions and Al(1 1 1) surfaces by application of a numerical code which can include all the relevant charge exchange mechanisms. Our analysis is based on comparisons between calculated angular distributions of scattered species and experimental data for two different representations of the image potentials. We found that angular distributions produced by the collective surface-plasmon mode of ion neutralization are consistent in peak's position and angular range with the experimental results. The high of the calculated angular distribution is below the experimental one which indicates the need to consider the electron-hole excitation mode and possibly some other modes like those related to multipole surface-plasmon and bulk-plasmon emission. The present study shows the sensitivity of the calculated angular distributions to the scattering potentials and it also enlightens the important role play...

  17. Theoretical Concepts for Ultra-Relativistic Heavy Ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    McLerran,L.

    2009-07-27

    Various forms of matter may be produced in ultra-relativistic heavy ion collisions. These are the Quark GluonPlasma, the Color Glass Condensate , the Glasma and Quarkyoninc Matter. A novel effect that may beassociated with topological charge fluctuations is the Chiral Magnetic Effect. I explain these concepts andexplain how they may be seen in ultra-relatvistic heavy ion collisions

  18. Theoretical studies of slow collisions. Elastic electron scattering from positive ions, charge transfer in one-electron ion-ion systems and mutual neutralization of H-/D- and H2+

    International Nuclear Information System (INIS)

    Quantal and semi-classical methods have been used to investigate slow electron, ionic and molecular collisions. Three distinct areas have been considered: the elastic scattering of electrons from positive ions, the symmetric resonance charge transfer in one-electron ion-ion collisions and the mutual neutralization of the hydrogen molecular ion and the negative hydrogen or deuterium ion. Differential cross sections for the elastic scattering of electrons from the closed-shell ions Na+, Cs+, Mg2+, N3+ and Ar8+ were obtained employing model and psuedopotential and quantum defect methods in a partial-wave analysis. Results were found to be consistent with recent experiments (Williams 1999 Rep. Prog. Phys. 62 1431) for Na+ and N3+, but less good agreement was obtained for Cs+ and Ar8+. The symmetric resonance charge transfer reaction AZ+ + A(Z-1)+ (1s) → A(Z-1)+ (1s) + AZ+ with Z > 1 has been investigated. In particular, differential cross sections for charge transfer in the 4He+-3He2+ system were determined in the perturbed stationary states approximation. These two-state semi-classical calculations were found to be in excellent agreement with fully quantal calculations of Falcon (1983 J. Phys. B: At. Mol. Phys. 16 1793), and in reasonable agreement with calculations and experiment of Kruedener et al (1997 Phys.Rev. Lett. 79 1002). Total cross sections for this and iso-electronic systems were found to agree with simple approximations. Total cross sections for the mutual neutralization reaction H2+ + D- → H2(1s, nl) + D(1s) + Δε were found using the Landau-Zener curve-crossing model. This method of calculation is heavily dependent on the reliability of estimates of the coupling matrix elements. Potential energy curves for the H2 molecule were found using the MOLPRO package in order to have a consistent base from which to determine the energetics of the reaction. Agreement with early experiments of Aberth et al (1971 AFCRL Report No. 71-0481 Bedford, Mass.) is

  19. Collision and recombination driven instabilities in variable charged dusty plasmas

    Indian Academy of Sciences (India)

    S Bal; M Bose

    2013-04-01

    The dust-acoustic instability driven by recombination of electrons and ions on the surface of charged and variably-charged dust grains as well as by collisions in dusty plasmas with significant pressure of background neutrals have been theoretically investigated. The recombination driven instability is shown to be dominant in the long wavelength regime even in the presence of dust-neutral and ion-neutral collisions, while in the shorter wavelength regime, the dust-neutral collision is found to play a major role. In an earlier research work, the dust-neutral collision was neglected in comparison to the effect due to the recombination for estimating the dust-acoustic instability; later the other report shows that the recombination effect is negligible in the presence of dust-neutral collisions. In line of this present situation our investigation revealed that the recombination is more important than dust-neutral collisions in laboratory plasma and fusion plasma, while the dust-neutral collision frequency is dominant in the interstellar plasmas. The effects of ion and dust densities and ion streaming on the recombination and collision driven mode in parameter regimes relevant for many experimental studies on dusty plasmas have also been calculated.

  20. Effects of autoionization in electron loss from helium-like highly charged ions in collisions with photons and fast atomic particles

    CERN Document Server

    Lyashchenko, K N; Voitkiv, A B

    2016-01-01

    We study theoretically single electron loss from helium-like highly charged ions involving excitation and decay of autoionizing states of the ion. Electron loss is caused by either photo absorption or the interaction with a fast atomic particle (a bare nucleus, a neutral atom, an electron). The interactions with the photon field and the fast particles are taken into account in the first order of perturbation theory. Two initial states of the ion are considered: $1s^2$ and $(1s2s)_{J=0}$. We analyze in detail how the shape of the emission pattern depends on the atomic number $Z_{I}$ of the ion discussing, in particular, the inter-relation between electron loss via photo absorption and due to the impact of atomic particles in collisions at modest relativistic and extreme relativistic energies. According to our results, in electron loss from the $1s^2$ state autoionization may substantially influence the shape of the emission spectra only up to $Z_{I} \\approx 35-40$. A much more prominent role is played by autoi...

  1. Some electron detachment data for H- ions in collisions with electrons, ions, atoms and molecules

    International Nuclear Information System (INIS)

    In order to provide information on the effectiveness of the conversion of negative hydrogen ions in collision with multiply charged ions into neutrals for plasma heating, the present situation is reviewed on the cross sections involving negative hydrogen ions in collisions with electrons, ions, atoms and molecules. It is pointed out that, though electron detachment from negative hydrogen ions is estimated to be effectively achievable under collisions with multiply charged ions, reliable data for such processes are still scanty in particular at the MeV/amu energy range and measurements of the cross sections are deserved to be performed urgently. (author)

  2. LHCb results from proton ion collisions

    OpenAIRE

    Massacrier, Laure

    2015-01-01

    Proton-lead and lead-proton data taking during 2013 has allowed LHCb to expand its physics program to heavy ion physics. Results include the first forward measurement of Z production in proton-lead collisions as well as a measurement of the nuclear modification factor and forward-backward production of prompt and displaced J/$\\psi$, $\\psi$(2S) and $\\Upsilon$. Angular particle correlations have also been measured for events of varying charged particle activity.

  3. LHCb results from proton ion collisions

    OpenAIRE

    Massacrier Laure

    2016-01-01

    Proton-lead and lead-proton data taking during 2013 has allowed LHCb to expand its physics program to heavy ion physics. Results include the first forward measurement of Z production in proton-lead collisions as well as a measurement of the nuclear modification factor and forward-backward production of prompt and displaced J/ψ, ψ(2S) and ϒ. Angular particle correlations have also been measured for events of varying charged particle activity.

  4. Heavy ion collisions

    International Nuclear Information System (INIS)

    The status of research into collisions of nuclei at high energy is reviewed. Reactions and products are classified, and spectator matter is discussed. Then the thermalization of participant matter is considered at some length. Finally, disintegration of the hot matter is addressed. A = 20 and 40 projectiles of 250 to 1050 MeV/A are employed to illustrate the major points. 44 references, 10 figures

  5. Seventh international seminar on ion-atom collisions (ISIAC VII): summary

    International Nuclear Information System (INIS)

    The scientific program was structured into eight symposia representing seven important research areas. The subject matter was expanded to include ion-molecule collisions as one of the eight symposia. The symposia were: (1) collisions involving strong binding phenomena and nuclear effects; (2) low-energy, high charge state collisions; (3) Rydberg states; (4) an Open Session; (5) ion-molecule collisions; (6) laser applications to atomic and molecular collisions; (7) collision spectroscopy; and (8) polarization, alignment and correlation

  6. Observation of Charge Asymmetry Dependence of Pion Elliptic Flow and the Possible Chiral Magnetic Wave in Heavy-Ion Collisions

    Czech Academy of Sciences Publication Activity Database

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Bielčík, J.; Bielčíková, Jana; Chaloupka, P.; Federič, Pavol; Rusňák, Jan; Rusňáková, O.; Šimko, Miroslav; Šumbera, Michal; Tlustý, David; Trzeciak, B. A.; Vértési, Robert

    2015-01-01

    Roč. 114, č. 25 (2015), s. 252302. ISSN 0031-9007 R&D Projects: GA ČR GA13-20841S; GA MŠk LA09013 Institutional support: RVO:61389005 Keywords : STAR collaboration * relativistic nuclear collisions Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 7.512, year: 2014

  7. Timescales in heavy ion collisions

    CERN Document Server

    Lisa, Mike

    2016-01-01

    The study of high energy collisions between heavy nuclei is a field unto itself, distinct from nuclear and particle physics. A defining aspect of heavy ion physics is the importance of a bulk, self-interacting system with a rich space-time substructure. I focus on the issue of timescales in heavy ion collisions, starting with proof from low-energy collisions that femtoscopy can, indeed, measure very long timescales. I then discuss the relativistic case, where detailed measurements over three orders of magnitude in energy reveal a timescale increase that might be due to a first-order phase transition. I discuss also consistency in evolution timescales as determined from traditional longitudinal sizes and a novel analysis using shape information.

  8. Measuring charge fluctuations in high-energy nuclear collisions

    OpenAIRE

    Mrowczynski, Stanislaw

    2001-01-01

    Various measures of charge fluctuations in heavy-ion collisions are discussed. Advantages of the Phi-measure are demonstrated and its relation to other fluctuation measures is established. To get the relation, Phi is expressed through the moments of multiplicity distribution. We study how the measures act in the case of a `background' model which represents the classical hadron gas in equilibrium. The model assumes statistical particle production constrained by charge conservation. It also ta...

  9. Observation of charge-dependent azimuthal correlations and possible local strong parity violation in heavy-ion collisions

    Czech Academy of Sciences Publication Activity Database

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Anderson, B.D.; Arkhipkin, D.; Averichev, G. S.; Badyal, S. K.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D.R.; Bellwied, R.; Benedosso, F.; Betancourt, M.J.; Betts, R. R.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielčík, Jaroslav; Bielčíková, Jana; Biritz, B.; Bland, L.C.; Bnzarov, I.; Bombara, M.; Bonner, B.E.; Bouchet, J.; Braidot, E.; Brandin, A.V.; Bruna, E.; Bueltmann, S.; Burton, T.P.; Bysterský, Michal; Cai, X.Z.; Caines, H.; Calderon, M.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M.C.; Chajecki, Z.; Chaloupka, Petr; Chattopadhyay, S.; Chen, H.F.; Chen, J.H.; Chen, J.Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K.E.; Christie, W.; Clarke, R.F.; Codrington, M.J.M.; Corliss, R.; Cormier, T.M.; Cosentino, M.R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Das, S.; Dash, S.; Daugherity, M.; De Silva, L.C.; Dedovich, T. G.; DePhillips, M.; Derevschikov, A.A.; de Souza, R.D.; Didenko, L.; Djawotho, P.; Dogra, S.M.; Dong, X.; Drachenberg, J.L.; Draper, J. E.; Dunlop, J.C.; Mazumdar, M.R.D.; Efimov, L.G.; Elhalhuli, E.; Elnimr, M.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L. (ed.); Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gaillard, L.; Gangaharan, D.R.; Ganti, M.S.; Garcia-Solis, E.J.; Geromitsos, A.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y.N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S.M.; Guimaraes, K.S.F.F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T.J.; Hamed, A.; Harris, J.W.; He, W.; Heinz, M.; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A.M.; Hoffmann, G.W.; Hofman, D.J.; Hollis, R.S.; Huang, H.Z.; Humanic, T.J.; Huo, L.; Igo, G..; Lordanova, A.; Jacobs, P.; Jacobs, W.W.; Jakl, Pavel; Jena, C.; Jin, F.; Jones, C.L.; Jones, P.G.; Joseph, J.; Judd, E.G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitán, Jan; Kauder, K.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V.Yu.; Kikola, D.P.; Kiryluk, J.; Kisiel, A.; Klein, S.R.; Knospe, A.G.; Kocoloski, A.; Koetke, D.D.; Konzer, J.; Kopytine, M.; Koralt, I.; Korsch, W.; Kotchenda, L.; Kushpil, Vasilij; Kravtsov, P.; Kravtsov, V.I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M.A.C.; Landgraf, J.M.; LaPointe, S.; Lauret, J.; Lebedev, A.; Lednický, Richard; Lee, Ch.; Lee, J.H.; Leight, W.; LeVine, M.J.; Li, C.; Li, N.; Li, Y.; Lin, G.; Lindenbaum, S.J.; Lisa, M.A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W.J.; Longacre, R.S.; Love, W.A.; Lu, Y.; Ludlam, T.; Ma, G.L.; Ma, Y.G.; Mahapatra, D.P.; Majka, R.; Mall, O.I.; Mangotra, L.K.; Manweiler, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H.S.; Matulenko, Yu.A.; McDonald, D.; McShane, T.S.; Meschanin, A.; Millner, R.; Minaev, N.G.; Mioduszewski, S.; Mischke, A.; Mohanty, B.; Mondal, M.M.; Morozov, D.A.; Munhoz, M. G.; Nandi, B.K.; Nattrass, C.; Nayak, T. K.; Nelson, J.M.; Netrakanti, P.K.; Ng, M.J.; Nogach, L.V.; Nurushev, S.B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B.S.; Pal, S.K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S.C.; Pile, P.; Planinic, M.; Ploskon, M.A.; Pluta, J.; Plyku, D.; Poljak, N.; Poskanzer, A.M.; Potukuchi, B.V.K.S.; Prindle, D.; Pruneau, C.; Pruthi, N.K.; Pujahari, P.R.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R.L.; Redwine, R.; Reed, R.; Ridiger, A.; Ritter, H.G.; Roberts, J.B.; Rogachevskiy, O.V.; Romero, J.L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M.J.; Sahoo, R.; Sakai, S.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R.P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S.S.; Shi, X.H.; Sichtermann, E.P.; Simon, F.; Singaraju, R.N.; Skoby, M.J.; Smirnov, N.; Sorensen, P.; Sowinski, J.; Spinka, H.M.; Srivastava, B.; Stanislaus, T.D.S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A.A.P.; Suarez, M.C.; Subba, N.L.; Šumbera, Michal; Sun, X.M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T.J.M.; de Toledo, A. S.; Takahashi, J.; Tang, A.H.; Tang, Z.; Tarini, L.H.; Tarnowsky, T.; Thein, D.; Thomas, J.H.; Tian, J.; Timmins, A.R.; Timoshenko, S.; Tlustý, David; Tokarev, M. V.; Trainor, T.A.; Tram, V.N.; Trattner, A.L.; Trentalange, S.; Tribble, R. E.; Tsai, O.D.; Ulery, J.; Ullrich, T.; Underwood, D.G.; Van Buren, G.; van Leeuwen, M.; van Nieuwenhuizen, G.; Vanfossen, J.A.; Varma, R.; Vasconcelos, G.M.S.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S.E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S.A.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J.S.; Wang, Q.; Wang, X.; Wang, X.L.; Wang, Y.; Webb, G.; Westfall, G.D.; Whitten, C.; Wieman, H.; Wissink, S.W.; Witt, R.; Wu, Y.; Xie, W.; Xu, N.; Xu, Q.H.; Xu, Y.; Xu, Z.; Yang, Y.; Yepes, P.; Yip, K.; Yoo, K.-Y.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, S.; Zhang, W.M.; Zhang, X.P.; Zhang, Y.; Zhang, Z.P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zhu, X.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zuo, J.X.

    2010-01-01

    Roč. 81, č. 5 (2010), 054908/1-054908/15. ISSN 0556-2813 R&D Projects: GA ČR GA202/07/0079; GA MŠk LA09013 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100502 Keywords : RELATIVISTIC NUCLEAR COLLISIONS * TIME PROJECTION CHAMBER * QUARK-GLUON PLASMA Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.416, year: 2010

  10. Theory of Electron-Ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, Donald C

    2009-10-02

    Collisions of electrons with atoms and ions play a crucial role in the modeling and diagnostics of fusion plasmas. In the edge and divertor regions of magnetically confined plasmas, data for the collisions of electrons with neutral atoms and low charge-state ions are of particular importance, while in the inner region, data on highly ionized species are needed. Since experimental measurements for these collisional processes remain very limited, data for such processes depend primarily on the results of theoretical calculations. Over the period of the present grant (January 2006 - August 2009), we have made additional improvements in our parallel scattering programs, generated data of direct fusion interest and made these data available on The Controlled Fusion Atomic Data Center Web site at Oak Ridge National Laboratory. In addition, we have employed these data to do collsional-radiative modeling studies in support of a variety of experiments with magnetically confined fusion plasmas.

  11. Charge-multiplicity and collision-energy dependence of $p_t$ spectra from $p$-$p$ collisions at the relativistic heavy-ion collider and large hadron collider

    CERN Document Server

    Trainor, Thomas A

    2016-01-01

    A two-component (soft + hard) model (TCM) of hadron production in yields and spectra derived from the charge-multiplicity dependence of 200 GeV $p$-$p$ collisions at the relativistic heavy ion collider (RHIC) is extended to describe $p$-$p$ spectrum data from the large hadron collider (LHC) up to 13 TeV. The LHC data include spectrum ratios that provide only partial information on the TCM. The LHC ratio method is first applied to well-understood RHIC spectrum data to derive an algebraic link between spectrum ratios and the full TCM. LHC spectrum ratios are then analyzed to obtain the collision-energy dependence of isolated soft and hard TCM spectrum components over three orders of magnitude. The energy dependence of the spectrum soft component is a new result suggesting a relation to Gribov diffusion. The spectrum hard component varies simply with QCD parameter $\\log(s/s_0)$ and is quantitatively consistent with minimum-bias jet spectra. Some aspects of the form of the hard component on transverse momentum ar...

  12. Charge Breeding of Radioactive Ions

    OpenAIRE

    Wenander, F. J. C.

    2014-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the phy...

  13. The fragment ion distribution of C60 in close collision with fast carbon ions

    International Nuclear Information System (INIS)

    We have measured the mass distribution of fragment ions of C60 produced by collisions with 15.6 MeV carbon ions in different charge states. Close collisions were selectively measured using the coincidence method with the change of the projectile charge state. For the electron capture and loss by C5+.6+ projectile ions, which are the K-electron processes, the multifragmentation was observed evidently. In L-electron loss channels of the C2+ projectile, the peaks of the multiply ionized C60 ions and the multiply ionized fullerene-like fragment ions are more intense or as intense as the small fragment ions. (author)

  14. Collision studies involving C60 (Buckminsterfullerene) ions

    International Nuclear Information System (INIS)

    The discovery of the exceptional stability of C60 (Buckminsterfullerene) and its ions has prompted a large number of experimental and theoretical investigations concerning this soccerball-shaped molecule. After the discovery of a method, by which macroscopic quantities of C60 are available, this molecule has become an obvious candidate for structural and dynamic investigations by atomic-collision experiments. In our experiments, the fragment distributions suggest a mechanism where fragmentation occurs by sequential loss of 'pairs' of carbon atoms. We have continued the C+60 fragmentation studies and also included negative and multiply charged as well as other fullerene ions besides C60. In the case of positive fullerenes, only even-numbered molecules were observed, but for the negative fullerenes, also odd-numbered molecules were recorded on the ∼ 0.5% level relative to the even-numbered components. This finding indicates that the electron structure also plays an important role for the stability of fullerene ions, or perhaps that negative molecules can exist in some isomeric form. The total destruction cross sections for fullerene ions have been measured in several target gases. We are planning to continue with collisional studies of various fullerene ions with special emphasis on a better understanding of the collisionally induced fragmentation for ions in well prepared states, and also endohedral complexes and fusion will be investigated in collision studies. (EG) (8 refs.)

  15. Grazing Ion-Surface Collisions

    Science.gov (United States)

    Gravielle, M. S.

    Electron emission after grazing ion-surface collisions is studied for high impact velocities. We have focused on glancing angles of electron emission where the dominant mechanism is the ionization from atomic bound states. To describe this process, we introduce a quantum model called field distorted-wave (FDW) approximation, which takes into account the effect of the surface interaction on the electronic transition. The FDW model is applied to analyze electron distributions produced by impact of protons on Al and LiF surfaces, which are metal and insulator materials respectively. In the case of metals, we also evaluate the contibution coming from the valence band by employing the binary collisional formalism. Calculated electron emission yields are in reasonable agreement with the available experimental data. We find that the maximum of the convoy electron distribution is accelerated for Al and decelerated for LiF, with respect to its position in ion-atom collisions, in quantitative accordance with experiments.

  16. Charge-transfer cross sections of ground state He+ ions in collisions with He atoms and simple molecules in the energy range below 4.0 keV

    International Nuclear Information System (INIS)

    Charge-transfer cross sections of the ground state He+ ions in collisions with He atoms and simple molecules (H2, D2, N2, CO and CO2) have been measured in the energy range of 0.20 to 4.0 keV with the initial growth rate method. Since previously published experimental data are scattered in the low energy region, the present observations would provide reasonably reliable cross section data below 4 keV. The charge transfer accompanied by dissociation of product molecular ion can be dominant at low energies for molecular targets. In He+ + D2 collisions, any isotope effect was not observed over the present energy range, compared to H2 molecule. (author)

  17. Central collisions of heavy ions

    International Nuclear Information System (INIS)

    This report describes the activities of the Heavy Ion Physics Group at the University of California, Riverside from October 1, 1991 to September 30, 1992. During this period, the program focused on particle production at AGS energies, and correlation studies at the Bevalac in nucleus-nucleus central collisions. As part of the PHENIX collaboration, contributions were made to the Preliminary Conceptual Design Report (pCDR), and work on a RHIC silicon microstrip detector R ampersand D project was performed

  18. A trapped ion source with improved ionizing efficiency for the production of multiply charged ions

    International Nuclear Information System (INIS)

    An ultrahigh vacuum 'trapped ion source' has been developed following closely Redhead's basic design. Positive ions have been trapped within the space charge of a magnetically confined electron beam with potential barriers at either end of the ionization region, resulting in the production of multiply charged ions. These highly stripped ions are formed by the successive collisions with low energy (0 mass spectrometer. The results obtained in the production of multiply charged ions of Au are presented. (auth.)

  19. X-UV SPECTROSCOPY OF LOW ENERGY CHARGE EXCHANGE COLLISIONS

    OpenAIRE

    Bliman, S.; Bonnet, J.; Bonnefoy, M.; Dousson, S.; Fleury, A.; Hitz, D.; Lu Dac, T.; Mayo, M.

    1986-01-01

    In the field of hot plasmas, it is well known that a knowledge of the relation between collisions and radiation is needed. We show that considering the charge exchange process in which a highly charged, low velocity ion impinges on an atom, we have an X-UV light source allowing new developments. Basically, at velocities less than the atomic unit (vo = 2.2 108 cm/s), the capture of one electron will leave the projectile ion in an excited state. The most probably populated level np is dependant...

  20. Electron emission following collisions between multi-charged ions and D{sub 2} molecules; Etude de l'emission electronique induite par impact d'ion multicharge sur la molecule D{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, G

    2004-05-15

    Dissociative ionisation mechanisms induced in collisions involving a highly charged ion (S{sup 15+}, 13.6 MeV/u) and a molecular deuterium target, have been studied through momentum vector correlations of both the D{sup +} fragments and the electrons produced. An experimental apparatus has been developed in order to detect in coincidence all the charged particles produced during the collision. The measurement of their momentum vectors, which allows one to determine both their kinetic energy and direction of emission with respect to the projectile one, combines Time of Flight, Position Sensitive Detection, and multi-coincidence techniques. The correlation of the fragment and electron kinetic energies enables not only to determine branching ratios between the dissociative ionisation pathways, but also to separate unambiguously kinetic energy distributions of fragments associated to each process. Finally, the angular distributions of ejected electrons, as a function of the orientation of the molecular axis with respect to the projectile direction, are deduced from the spatial correlation. Measurements are compared to theoretical angular distributions obtained using the CDW-EIS (Continuum Distorted Wave-Eikonal Initial State) method. (author)

  1. Relevant effects of localized atomic interactions and surface density of states on charge transfer in ion-surface collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bonetto, F.; Romero, M.A.; Garcia, E.A.; Vidal, R.; Ferron, J.; Goldberg, E.C. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Santa Fe (Argentina); Ferron, J.; Goldberg, E.C. [Universidad Nacional del Litoral, J., Dept. de Ingenieria de Materiales, Facultad de Ingenieria Quimica, Santa Fe (Argentina)

    2007-12-15

    Through a time-dependent quantum-mechanical calculation of the H{sup +} scattering by a highly oriented pyrolytic graphite (HOPG) surface, we are able to satisfactorily reproduce the interesting features we observed in ion scattering experiments in H{sup +}/HOPG system. We found that the combined effects of the semimetal character of HOPG together with the localized nature of the carbon atom states primarily determine the angular dependence and the magnitude of the ion fractions for large outgoing angles. The spin fluctuation effects (not considered in the present calculation) are discussed as one of the the main causes of the disagreement between the spinless theory results and the experiments for small exit angles. (authors)

  2. Effect of collisions on dust particle charging via particle-in-cell Monte-Carlo collision

    Science.gov (United States)

    Rovagnati, B.; Davoudabadi, M.; Lapenta, G.; Mashayek, F.

    2007-10-01

    In this paper, the effect of collisions on the charging and shielding of a single dust particle immersed in an infinite plasma is studied. A Monte-Carlo collision (MCC) algorithm is implemented in the particle-in-cell DEMOCRITUS code to account for the collisional phenomena which are typical of dusty plasmas in plasma processing, namely, electron-neutral elastic scattering, ion-neutral elastic scattering, and ion-neutral charge exchange. Both small and large dust particle radii, as compared to the characteristic Debye lengths, are considered. The trends of the steady-state dust particle potential at increasing collisionality are presented and discussed. The ions and electron energy distributions at various locations and at increasing collisionality in the case of large particle radius are shown and compared to their local Maxwellians. The ion-neutral charge-exchange collision is found to be by far the most important collisional phenomenon. For small particle radius, collisional effects are found to be important also at low level of collisionality, as more ions are collected by the dust particle due to the destruction of trapped ion orbits. For large particle radius, the major collisional effect is observed to take place in proximity of the presheath. Finally, the species energy distribution functions are found to approach their local Maxwellians at increasing collisionality.

  3. Non abelian hydrodynamics and heavy ion collisions

    Science.gov (United States)

    Calzetta, E.

    2014-01-01

    The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined by the conservation laws of energy momentum and color currents. Therefore it is possible to describe its main features in hydrodynamic terms, the very short color neutralization time notwithstanding. In this lecture we shall give a simple derivation of the hydrodynamics of a color charged fluid, by generalizing the usual derivation of hydrodynamics from kinetic theory to the non abelian case.

  4. Non abelian hydrodynamics and heavy ion collisions

    CERN Document Server

    Calzetta, Esteban

    2013-01-01

    The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined by the conservation laws of energy momentum and color currents. Therefore it is possible to describe its main features in hydrodynamic terms, the very short color neutralization time notwithstanding. In this lecture we shall give a simple derivation of the hydrodynamics of a color charged fluid, by generalizing the usual derivation of hydrodynamics from kinetic theory to the non abelian case.

  5. Non abelian hydrodynamics and heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Calzetta, E. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina)

    2014-01-14

    The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined by the conservation laws of energy momentum and color currents. Therefore it is possible to describe its main features in hydrodynamic terms, the very short color neutralization time notwithstanding. In this lecture we shall give a simple derivation of the hydrodynamics of a color charged fluid, by generalizing the usual derivation of hydrodynamics from kinetic theory to the non abelian case.

  6. Charge Breeding of Radioactive Ions

    CERN Document Server

    Wenander, F J C

    2013-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the physics processes involved in the production of highly charged ions will be introduced, and the injection and extraction beam parameters of the charge breeder defined. A description of the three main charge-breeding methods is given, namely: electron stripping in gas jet or foil; external ion injection into an electron-beam ion source/trap (EBIS/T); and external ion injection into an electron cyclotron resonance ion source (ECRIS). In addition, some preparatory devices for charge breeding and practical beam delivery aspects ...

  7. Heavy ion collisions and cosmology

    CERN Document Server

    Floerchinger, Stefan

    2015-01-01

    There are interesting parallels between the physics of heavy ion collisions and cosmology. Both systems are out-of-equilibrium and relativistic fluid dynamics plays an important role for their theoretical description. From a comparison one can draw interesting conclusions for both sides. For heavy ion physics it could be rewarding to attempt a theoretical description of fluid perturbations similar to cosmological perturbation theory. In the context of late time cosmology, it could be interesting to study dissipative properties such as shear and bulk viscosity and corresponding relaxation times in more detail. Knowledge and experience from heavy ion physics could help to constrain the microscopic properties of dark matter from observational knowledge of the cosmological fluid properties.

  8. Effect of Coulomb collision on the negative ion extraction mechanism in negative ion sources

    International Nuclear Information System (INIS)

    To improve the H− ion beam optics, it is necessary to understand the energy relaxation process of surface produced H− ions in the extraction region of Cs seeded H− ion sources. Coulomb collisions of charged particles have been introduced to the 2D3V-PIC (two dimension in real space and three dimension in velocity space particle-in-cell) model for the H− extraction by using the binary collision model. Due to Coulomb collision, the lower energy part of the ion energy distribution function of H− ions has been greatly increased. The mean kinetic energy of the surface produced H− ions has been reduced to 0.65 eV from 1.5 eV. It has been suggested that the beam optics of the extracted H− ion beam is strongly affected by the energy relaxation process due to Coulomb collision

  9. Atomic physics with highly charged ions. Progress report, 15 February 1985-14 February 1986

    International Nuclear Information System (INIS)

    The experimental program has three directions: the study of collisions of very low velocity, highly-charged secondary recoil ions with stationary gas atoms, the study of collisions of high velocity, highly-charged ions with stationary targets, and the study of the theoretical descriptions of atomic collisions and atomic structure properties of highly-charged ions. Brief reports of the progress in these areas are given

  10. Future directions in electron--ion collision physics

    International Nuclear Information System (INIS)

    This report discusses the following topics: Summary of session on synergistic co-ordination of theory and experiment; synergism between experiment and theory in atomic physics; comparison of theory and experiment for electron-ion excitation and ionization; summary of session on new theoretical and computational methods; new theoretical and computational methods-r-matrix calculations; the coulomb three-body problem: a progress report; summary of session on needs and applications for electron-ion collisional data; electron-ion collisions in the plasma edge; needs and applications of theoretical data for electron impact excitation; summary of session on relativistic effects, indirect effects, resonance, etc; direct and resonant processes in electron-ion collisions; relativistic calculations of electron impact ionization and dielectronic recombination cross section for highly charged ions; electron-ion recombination in the close-coupling approximation; modified resonance amplitudes with strongly correlated channels; a density-matrix approach to the broadening of spectral lines by autoionization, radiative transitions and electron-ion collisions; towards a time-dependent description of electron-atom/ion collisions two electron systems; and comments on inclusion of the generalized bright interaction in electron impact excitation of highly charged ions

  11. Collisions of oppositely charged black holes

    CERN Document Server

    Zilhão, Miguel; Herdeiro, Carlos; Lehner, Luis; Sperhake, Ulrich

    2013-01-01

    The first fully non-linear numerical simulations of colliding charged black holes in D=4 Einstein-Maxwell theory were recently reported arXiv:1205.1063. These collisions were performed for black holes with equal charge-to-mass ratio, for which initial data can be found in closed analytic form. Here we generalize the study of collisions of charged black holes to the case of unequal charge-to-mass ratios. We focus on oppositely charged black holes, as to maximize acceleration-dependent effects. As |Q|/M increases from 0 to 0.99, we observe that the gravitational radiation emitted increases by a factor of ~ 2.7; the electromagnetic radiation emission becomes dominant for |Q|/M >~ 0.37 and at |Q|/M=0.99 is larger, by a factor of ~ 5.8, than its gravitational counterpart. We observe that these numerical results exhibit a precise and simple scaling with the charge. Furthermore, we show that the results from the numerical simulations are qualitatively captured by a simple analytic model that computes the electromagn...

  12. Self-interaction effects on charge-transfer collisions

    CERN Document Server

    Quashie, Edwin E; Andrade, Xavier; Correa, Alfredo A

    2016-01-01

    In this article, we investigate the role of the self-interaction error in the simulation of collisions using time-dependent density functional theory (TDDFT) and Ehrenfest dynamics. We compare many different approximations of the exchange and correlation potential, using as a test system the collision of $\\mathrm{H^+ + CH_4}$ at $30~\\mathrm{eV}$. We find that semi-local approximations, like PBE, and even hybrid functionals, like B3LYP, produce qualitatively incorrect predictions for the scattering of the proton. This discrepancy appears because the self-interaction error allows the electrons to jump too easily to the proton, leading to radically different forces with respect to the non-self-interacting case. From our results, we conclude that using a functional that is self-interaction free is essential to properly describe charge-transfer collisions between ions and molecules in TDDFT.

  13. Ionization and fragmentation of cold clusters of PAH molecules: collisions with keV ions

    International Nuclear Information System (INIS)

    We report on collisions between atomic ions and pure, loosely bound, clusters of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We find that charge and excitation energy is distributed on the cluster constituents before break-up which mostly leads to emissions of intact, excited, singly charged monomers. Surprisingly, collisions with highly charged ions lead to hotter monomers than collisions with ions in low charge states. Small PAH clusters fragment promptly when singly ionized while clusters of more than 13 or 5 molecules may remain intact for anthracene or coronene clusters, respectively.

  14. Collision Rates in Charged Granular Gases

    OpenAIRE

    Scheffler, T. (Thomas); Wolf, D. E.

    2002-01-01

    The dissipation rate due to inelastic collisions between equally charged, insulating particles in a granular gas is calculated. It is equal to the known dissipation rate for uncharged granular media multiplied by a Boltzmann-like factor, that originates from Coulomb repulsion. Particle correlations lead to an effective potential that replaces the bare Coulomb potential in the Boltzmann factor. Collisional cooling in a granular gas proceeds with the known t^-2 -law, until the kinetic energy of...

  15. Ion distribution functions in cylindrically symmetric electric fields in the auroral ionosphere: the collision-free case in a uniformly charged configuration

    CERN Document Server

    Ma, John Z G

    2010-01-01

    The aurora often breaks down into elongated filaments that are aligned with the geomagnetic field. It is natural to infer from this that when important structures are found in the electrostatic fields they, too, will follow a cylindrical geometry. With ionospheric applications in mind, we have therefore studied the response of the ion distribution function and its transport properties to the sudden introduction of an electric field which increases linearly with radial distance. In this first study we have considered collision-free conditions. We have solved the attendant Boltzmann equation by tracking the ions back in time, thereby using the temporal link between the initial position and velocity of an ion and the position and velocity at an arbitrary time and place. We have obtained a complete analytical solution for the ion trajectories and the ion distribution function, in addition to the transport properties, for all values of time and space. We have found that individual ions gyrate in phase at a frequen...

  16. Anisotropic emission of charged mesons and structure characteristic of emission source in heavy ion collisions at 1-2A GeV

    Institute of Scientific and Technical Information of China (English)

    Liu Fu-Hu

    2008-01-01

    Angular distributions of pions and kaons produced in heavy ion collisions at the low-energy end of high energies (1-2 A GeV) have been investigated by using a multisource ideal gas model.The model covers the expansions and movements of the emission sources, and it is related to the collective flows. By using the analytic expression and the Monte Carlo method, the azimuthal and polar angle distributions of mesons are calculated by the model and compared with the experimental data of the KaoS Collaboration.

  17. Results of heavy ion collisions at LHCb

    CERN Document Server

    Zhang, Yanxi

    2016-01-01

    Heavy flavor production is important in heavy ion collisions to study both cold and hot nuclear matter effects. The LHCb experiment can make unique contribution to heavy ion physics, owing to the full particle identification of the detector in the forward region and the ability to collect fixed target data with proton or lead beams. This report describes recent results with proton-lead collision data collected in 2013 and the prospect of heavy-ion studies at LHCb.

  18. Results on heavy ion collisions at LHCb

    CERN Document Server

    Zhang, Yanxi

    2016-01-01

    Heavy flavor production is important in heavy ion collisions to study both cold and hot nuclear matter effects. The LHCb experiment can make unique contribution to heavy ion physics, owing to the full particle identification of the detector in the forward region and the ability to collect fixed target data with proton or lead beams. This report describes recent results with proton-lead collision data collected in 2013 and the prospect of heavy-ion studies at LHCb.

  19. Collision physics with highly stripped slow ions

    International Nuclear Information System (INIS)

    A review about recent studies with highly stripped heavy ions is given. Its scope is limited to mainly inner shell processes and slow collisions compared to the Bohr velocity of electrons in these shells. The processes discussed are: population of excited states by electron capture in asymmetric collision systems; electron capture and excitation in symmetric collisions with an emphasis on the impact parameter dependence of K- to L-shell and K- to K-shell vacancy transfer; the interference structure in the quasimolecular X-rays from slow hydrogen-like ion-atom collisions which is used for direct spectroscopy of quasimolecular energies. (Auth.)

  20. Ionization of helium in relativistic heavy-ion collisions

    OpenAIRE

    Barna, Imre Ferenc

    2002-01-01

    The coupled-channel method is used to calculate single-, and double-ionisation cross sections for helium collisions with heavy ions. For highly charged and slow projectiles where the ratio of the projectile charge divided by the projectile velocity is in the magnitude of unity, non-perturbative methods must be used for proper description of the physical process. As basis functions Slater-like orbitals and regular Coulomb wave packages were taken. The Coulomb wave packages give a satisfacto...

  1. Multiple Electron Capture Processes in Slow Collisions of Ar9+ Ions with Na Atoms

    Institute of Scientific and Technical Information of China (English)

    ZhuXiaolong; ShaShan; LiuHuiping; WeiBaoren; MaXinwen; WangZhengling; CaoShiping; QianDongbing; YangZhihu

    2003-01-01

    Slow collisions of highly charged ions with neutral atoms and molecules are of great importance in basic atomic collision physics, Recently, we built a new research facility for atomic physics at the Institute of Modern Physics. We report here the multiple electron transfer processes in collisions of Ar9+ with Na gas target at energy of 180 keV.

  2. Saturation effect in projectile- and target- x-ray production in collisions between 2.5 MeV/u highly charged Cu ions and gaseous targets

    Science.gov (United States)

    Kumar, Ajay; Misra, D.; Kelkar, A. H.; Kadhane, U.; Singh, Y. P.; Lapicki, G.; Gulyas, L.; Tribedi, L. C.

    2006-01-01

    L x-ray production cross sections have been measured for highly charged 2.5 MeV/u Cuq+ (q = 20-26) ions colliding with H2, Ne, Ar, Kr and Xe target atoms. The observed Cu L x-rays are due to the excitation and electron-transfer processes. The charge state dependence of the projectile L x-rays has been studied with Ar and Kr targets. We have derived the subshell resolved K-L1, K-L2 and K-L3 electron-transfer cross sections from the measured Ar K x-ray yields as a function of L vacancies in Cu ion. The measured projectile L x-ray production cross sections arising from the excitation and electron capture are found to saturate as target atomic number Zt increases. Similarly, a saturation has also been found in the Ar K-shell ionization cross sections as a function of Zp.

  3. Multiplicity and Pseudorapidity distributions of charged particles in asymmetric and deformed nuclear collisions in a Wounded Quark Model

    OpenAIRE

    Chaturvedi, O. S. K.; P.K. Srivastava; Kumar, Ashwini; Singh, B. K.

    2016-01-01

    The charged particle multiplicity ($n_{ch}$) and pseudorapidity density $(dn_{ch}/d\\eta)$ are key observables to characterize the properties of matter created in heavy ion collisions. The dependence of these observables on collision energy and the collision geometry are a key tool to understand the underlying particle production mechanism. Recently a lot of focus on asymmetric nuclei as well as deformed nuclei collisions has been made as these collisions can provide a deeper understanding of ...

  4. Systematics of the charged-hadron P_T spectrum and the nuclear suppression factor in heavy-ion collisions from sqrt{s}=200 GeV to sqrt{s} =2.76 TeV

    CERN Document Server

    Renk, Thorsten; Paatelainen, Risto; Eskola, Kari J

    2011-01-01

    In this paper, our goal is to make a simultaneous analysis of the high- and low-P_T parts of the charged-hadron P_T spectrum measured by the ALICE collaboration in central Pb-Pb collisions at sqrt{s}=2.76 TeV at the Large Hadron Collider (LHC), based on models which have been successfully applied and constrained in Au-Au collisions at Relativistic Heavy Ion Collider (RHIC). For the hydrodynamical modeling with which we obtain the low-P_T spectrum, we have computed the initial conditions based on perturbative QCD (pQCD) minijet production and saturation. The sensitivity of the obtained charged-hadron P_T spectrum on the hydrodynamic model parameters is studied. For the high-P_T part, we apply a number of parton-medium interaction models, which are tuned to describe the nuclear suppression factor R_AA measured at the RHIC in central Au-Au collisions at sqrt{s}=200 GeV. We find that the higher kinematic reach of the LHC, manifest in the hardening of the pQCD parton spectral slope, is in principle very efficient ...

  5. Energy-resolved collision-induced dissociation of non-covalent ions: charge- and guest-dependence of decomplexation reaction efficiencies.

    Science.gov (United States)

    Carroy, Glenn; Lemaur, Vincent; De Winter, Julien; Isaacs, Lyle; De Pauw, Edwin; Cornil, Jérôme; Gerbaux, Pascal

    2016-05-14

    Supramolecular chemistry, and especially host-guest chemistry, has been the subject of great interest in the past few decades leading to the synthesis of host cage molecules such as calixarenes, cyclodextrins and more recently cucurbiturils. Mass spectrometry methods are increasingly used to decipher at the molecular level the non-covalent interactions between the different associated molecules. The present article illustrates that the association between mass spectrometry and computational chemistry techniques proves very complementary to depict the gas-phase dissociation processes of ionic non-covalent complexes when subjected to collisional activation. The selected system associates a nor-seco-cucurbit[10]uril bitopic receptor with different amino compounds (adamantylamine, para-xylylenediamine, and para-phenylenediamine). When subjected to CID experiments, the ternary complexes undergo fragmentation via dissociation of non-covalently bound partners. Interestingly, depending on their charge state, the collisionally excited complexes can selectively expel either a neutral guest molecule or a protonated guest molecule. Moreover, based on energy-resolved CID experiments, it is possible to evaluate the guest molecule dependence on the gas phase dissociation efficiency. We observed that the relative order of gas phase dissociation is charge state dependent, with the adamantylamine-containing complexes being the weakest when triply charged and the strongest when doubly charged. The energetics of the gas-phase dissociation reactions have been estimated by density functional theory (DFT) calculations. We succeeded in theoretically rationalizing the experimental collision-induced dissociation results with a special emphasis on: (i) the charge state of the expelled guest molecule and (ii) the nature of the guest molecule. PMID:27086657

  6. Photoproduction of top in peripheral heavy ion collisions

    CERN Document Server

    Klein, S R; Vogt, R; Klein, Spencer R.; Nystrand, Joakim; Vogt, Ramona

    2001-01-01

    In relativistic heavy ion collisions, top quarks can be produced by photon-gluon fusion when a photon from the Weizs\\"acker-Williams virtual photon field of one nucleus interacts with a gluon in the other nucleus. Photoproduction with heavy ions at the Large Hadron Collider (LHC) will be the first accessible non-hadronic top production channel. We calculate the $t \\bar t$ photoproduction cross sections, pair mass and top quark rapidity distributions in peripheral heavy ion collisions. The cross sections are sensitive to the top quark charge and the large-$Q^2$ gluon distribution in the nucleus. We find a cross section of 94 pb in calcium-calcium collisions, leading to 490 pairs in a one month LHC run. We also find $p$Pb and $p$Ca cross sections of 5.8 and 3.4 pb respectively, resulting in 15 and 88 $t\\bar t$ pairs per month.

  7. Electron detachment in ion-atom collisions

    International Nuclear Information System (INIS)

    The electron detachment process that occurs in negative ion-atom collisions is investigated. Differential cross sections were measured for the collisions of F-, Cl-, Br-, I- on He, Ne, Ar, Kr, Xe, Na and K. Electron energy distributions were obtained for some of the systems. (Auth.)

  8. Cosmology and elementary particles. Heavy ion collisions

    International Nuclear Information System (INIS)

    These school lectures were centered around two principal subjects: first tried to show how cosmology and particle physics are deeply related more and more nowadays. Second one was around heavy ion collisions and their relations with quark matter

  9. RELATIVISTIC HEAVY ION COLLISIONS: EXPERIMENT

    Energy Technology Data Exchange (ETDEWEB)

    Friedlander, Erwin M.; Heckman, Harry H.

    1982-04-01

    Relativistic heavy ion physics began as a 'no man's land' between particle and nuclear physics, with both sides frowning upon it as 'unclean', because on one hand, hadronic interactions and particle production cloud nuclear structure effects, while on the other, the baryonic environment complicates the interpretation of production experiments. They have attempted to review here the experimental evidence on RHI collisions from the point of view that it represents a new endeavor in the understanding of strong interaction physics. Such an approach appears increasingly justified; first, by the accumulation of data and observations of new features of hadronic interactions that could not have been detected outside a baryonic environment; second, by the maturation of the field owing to the advances made over the past several years in experimental inquiries on particle production by RHI, including pions, kaons, hyperons, and searches for antiprotons; and third, by the steady and progressive increase in the energy and mass ranges of light nuclear beams that have become available to the experiment; indeed the energy range has widened from the {approx} 0.2 to 2 AGeV at the Bevalac to {approx}4 AGeV at Dubna and recently, to the quantum jump in energies to {approx} 1000 equivalent AGeV at the CERN PS-ISR. Accompanying these expansions in the energy frontier are the immediate prospects for very heavy ion beams at the Bevalac up to, and including, 1 AGeV {sup 238}U, thereby extending the 'mass frontier' to its ultimate extent.

  10. Gaseous charge transfer reactions of multiply charged ions

    International Nuclear Information System (INIS)

    Doubly charged ions produced in electron impact ionization have received relatively little study due to their low abundance and masking from singly charged ions which are detected at the same mass-to-charge ratio by a mass spectrometer. This interference problem was avoided by exploiting a technique in which doubly charged molecular and fragment ions are monitored using a collisional charge-exchange process where only fast singly charged product ions are allowed to reach the detector. Primary research efforts were to determine structures and energetics of multiply charged ions formed in high energy electron impact ionization processes and their reactivities in ion-molecule charge exchange interactions. Doubly charged ion mass distributions for various chemical classes (including acetylenes, alkenes, terpenes and organophosphorus compounds) were recorded and appearance energies of prominent doubly charged ions were measured. Computer molecular orbital calculations (at the MINDO/3 level) of ionic structures, energies and charge distributions were utilized to augment the analysis of experimental results

  11. Ionization and electron emission of heavy ion-atom collisions: The argon-krypton collision system

    International Nuclear Information System (INIS)

    The Ar-Kr collision system has been studied by examining the charge states of the scattered ions together with the energies of the emitted electrons. The charge state data show that there are increases in the average scattered charge state at distances of closest approach that correspond well with internuclear distances for which the molecular orbital model1 predicts electron promotions of krypton and argon electrons to occur. The electron data show a well resolved Auger peak between 150-200 eV superimposed on an exponentially decreasing background of continuum electrons. Doppler shifts identify the Auger peak as originating from the argon collision partner. Ion-electron coincidence experiments exhibit the same peak and link it to a specific distance of closest approach. The threshold for this L-Auger electron production falls between 0.2 and 0.3 a.u., agreeing well with molecular orbital predictions

  12. Photons shedding light on electron capture by highly charged ions

    OpenAIRE

    Hoekstra, Romke Anne

    1990-01-01

    In this thesis charge transfer is studied in collisions of highly charged ions (Aq+) with neutral particles (B). Because the electron is captured resonantly (i.e. without its binding energy) by the ion, a limited number of highly excited states (characterized by the quantum numbers nlm) is preferentially populated. In the experimental work described in this thesis we have measured state selective electron capture cross sections by means of Photon Emission Spectroscopy. Especially, the most fu...

  13. Heavy flavour production at CMS in heavy ion collisions

    CERN Document Server

    Nguyen, Matthew

    2015-01-01

    We review recent results relating to beauty production in heavy-ion collisions, in both the closed and open heavy flavor sectors, from the CMS experiment at the LHC. The sequential suppression of the ° states in PbPb collisions is thought to be evidence of the dissociation of quarkonia bound states in deconfined matter. Data from pPb collisions demonstrate that while cold nuclear effects appear to be subdominant in minimum bias collisions, there exists a non-trivial dependence on collision multiplicity that remains to be understood. The suppression of high p T particles in heavy-ion collisions, relative to the expectation from pp collisions, is typically interpreted in terms of energy loss of hard scattered parton in the dense nuclear medium. The flavor dependence of the energy loss may be accessed via measurements of b hadrons and b-tagged jets. Measurement of B mesons, via non-prompt J = y , at relatively low p T indicate a smaller suppression factor than D meson or inclusive charged hadrons. Data on b jet...

  14. Charge-state-specific EUV spectra of Xe ions

    International Nuclear Information System (INIS)

    Charge state specific extreme ultraviolet spectra from xenon ions have been recorded at Tokyo Metropolitan University. The Electron Cyclotron Resonance Source spectra were produced from charge exchange collisions between the xenon ions and rare gas target atoms. Atomic structure calculations were performed for Xe 16+ − Xe20+ using the Hartree-Fock with Configuration Interaction code of Cowan and showed that the spectra arise from 4p-4d and 4d-4f transitions. In addition it was necessary to allow for selective capture processes that occur in these slow collisions. The energies of the capture states involved in the single electron process are estimated using the classical over barrier model.

  15. Atomic physics with highly charged ions

    International Nuclear Information System (INIS)

    The past year has been a busy one for all three accelerators, the LINAC, EBIS and the tandem. The EBIS continues to deliver beams of highly charged ions around the clock for the study of low energy collisions with gases and surfaces. The electron beam energy has been upgraded to 10 keV, and intensities of highly charged species such as Xe44+ have been greatly increased. The tandem, the traditional source of highly charged Binary encounter electron production at zero degrees were studied for medium Z (Si,Cl,Cu) projectiles. Recoil momentum spectroscopy has been used to separate the contributions to collisional ionization of one-electron ions (C5+, O7+, F8+) from the nucleus and the electrons of a He target. Marked structure in the binary encounter electron spectra for Cuq+ on H2 targets has been measured for moderate velocity projectiles. Electron capture by slow multiply charged (EBIS) projectiles from laser excited targets has been carried out. Cross sections for capture from Na(3s) and Na*(3p) have been measured for velocities between 0.1 and 1 au. The extension of these experiments to laser excited Rydberg targets is proceeding. Electron capture cross sections and average Q values for Ar16+ on He at velocities between 0.23 and 1.67 au have been measured. The charge state distribution of the He recoils following large angle scattering of C4+ and C6+ ions at 7.5 keV/u has been measured. Cross sections have been measured for up to sextuple capture from C60 (buckminsterfullerene) by highly charged slow projectiles. Coupled channel calculations for double capture from He by slow multicharge ions have been carried out

  16. Charge exchange between hydrogen atoms and fully stripped heavy ions

    International Nuclear Information System (INIS)

    Charge exchange between multicharged ions and background atomic and molecular gases represents one of the limitations to the attainment of high charge states in heavy ion sources, particularly containment sources. An attempt is made to study systematically a particularly simple but in many respects representative class of such reactions, namely charge transfer between atomic hydrogen and fully stripped heavy ions. Approximate cross sections for these processes in the low keV range of collision energies were obtained using a multistate Landau--Zener method. The energy and Z dependences of the cross sections are discussed

  17. Symmetric eikonal model for projectile-electron excitation and loss in relativistic ion-atom collisions

    OpenAIRE

    Voitkiv, A. B.; Najjari, B.; Shevelko, S. P.

    2010-01-01

    At impact energies $ \\stackrel{>}{\\sim}1$ GeV/u the projectile-electron excitation and loss occurring in collisions between highly charged ions and neutral atoms is already strongly influenced by the presence of atomic electrons. In order to treat these processes in collisions with heavy atoms we generalize the symmetric eikonal model, used earlier for considerations of electron transitions in ion-atom collisions within the scope of a three-body Coulomb problem. We show that at asymptotically...

  18. Charge equilibrium processes of energetic incident ions and their range

    International Nuclear Information System (INIS)

    The charge state of energetic ions passing through a certain matter is varied by charge-exchange processes. A rate equation for charge fraction is given by using electron loss and capture cross sections in collision with a target atom under idealized condition. We solved the rate equation of the charge-exchange process of a single electron in a form of linear coupled differential equation. Our calcuiation for the range of ion were carried out for He, Ne and Ar ions passing through an atomic hydrogen gas target. We discuss the charge states of the projectile in relation to a local charge balance consituting a state of charge equilibrium in the target. (author)

  19. Theory of heavy ion collisions. Annual progress report

    International Nuclear Information System (INIS)

    It is demonstrated clearly that macroscopic models account for many of the observed features of heavy ion collisions. During this phase of the program major steps have been taken toward a better understanding of fusion excitation function, strongly damped collisions, the emission of nucleons at intermediate energies, heavy ion collisions and pions in relativistic heavy ion collisions

  20. New state of nuclear matter: Nearly perfect fluid of quarks and gluons in heavy-ion collisions at RHIC energies. From charged particle density to jet quenching

    Science.gov (United States)

    Nouicer, R.

    2016-03-01

    This article reviews several important results from RHIC experiments and discusses their implications. They were obtained in a unique environment for studying QCD matter at temperatures and densities that exceed the limits wherein hadrons can exist as individual entities and raises to prominence the quark-gluon degrees of freedom. These findings are supported by major experimental observations via measuring of the bulk properties of particle production, particle ratios and chemical freeze-out conditions, and elliptic flow; followed by hard probe measurements: high- pT hadron suppression, dijet fragment azimuthal correlations, and heavy-flavor probes. These measurements are presented for particles of different species as a function of system sizes, collision centrality, and energy carried out in RHIC experiments. The results reveal that a dense, strongly interacting medium is created in central Au+Au collisions at sqrt{s_{NN}} = 200 GeV at RHIC. This revelation of a new state of nuclear matter has also been observed in measurements at the LHC. Further, the IP-Glasma model coupled with viscous hydrodynamic models, which assumes the formation of a QGP, reproduces well the experimental flow results from Au+Au at sqrt{s_{NN}} = 200 GeV. This implies that the fluctuations in the initial geometry state are important and the created medium behaves as a nearly perfect liquid of nuclear matter because it has an extraordinarily low ratio of shear viscosity to entropy density, η/s≈ 0.12. However, these discoveries are far from being fully understood. Furthermore, recent experimental results from RHIC and LHC in small p+A, d+ Au and 3He+Au collision systems provide brand new insight into the role of initial and final state effects. These have proven to be interesting and more surprising than originally anticipated; and could conceivably shed new light in our understanding of collective behavior in heavy-ion physics. Accordingly, the focus of the experiments at both

  1. Beyond the thermal model in relativistic heavy-ion collisions

    CERN Document Server

    Wolschin, Georg

    2016-01-01

    Deviations from thermal distribution functions of produced particles in relativistic heavy-ion collisions are discussed as indicators for nonequilibrium processes. The focus is on rapidity distributions of produced charged hadrons as functions of collision energy and centrality which are used to infer the fraction of produced particles from a central fireball as compared to the one from the fragmentation sources that are out of equilibrium with the rest of the system. Overall thermal equilibrium would only be reached for large times t -> infinity.

  2. [Relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    This report discusses the following topics: quark-hadron phase transition; hadron production without phase transition; fractal structure in multiparticle production; and j/psi suppression in pA collisions

  3. High-charge-state ion sources

    International Nuclear Information System (INIS)

    Sources of high charge state positive ions have uses in a variety of research fields. For heavy ion particle accelerators higher charge state particles give greater acceleration per gap and greater bending strength in a magnet. Thus higher energies can be obtained from circular accelerators of a given size, and linear accelerators can be designed with higher energy gain per length using higher charge state ions. In atomic physics the many atomic transitions in highly charged ions supplies a wealth of spectroscopy data. High charge state ion beams are also used for charge exchange and crossed beam experiments. High charge state ion sources are reviewed

  4. Identified charged hadron production in pp and Pb-Pb collisions with ALICE at the LHC

    OpenAIRE

    Vasileiou, Maria

    2015-01-01

    Nuclear matter under extreme conditions can be investigated in ultra-relativistic heavy-ion collisions. The measurement of transverse momentum distributions and yields of identified particles is a fundamental step in understanding collective and thermal properties of the matter produced in such collisions. The ALICE Experiment results on identified charged hadron production are presented for pp collisions at \\sqrt{s} = 0.9, 2.76 and 7 TeV and for Pb-Pb collisions at \\sqrt{s_{NN}} = 2.76 TeV. ...

  5. Effect of correlations on cumulants in heavy-ion collisions

    OpenAIRE

    Mishra, D K; Garg, P; Netrakanti, P. K.

    2015-01-01

    We study the effects of correlations on cumulants and their ratios of net-proton multiplicity distributions which have been measured for central (0\\%-5\\%) Au + Au collisions at the Relativistic Heavy Ion Collider (RHIC). This effect has been studied assuming individual proton and anti-proton distributions as a Poisson or Negative Binomial Distribution (NBD). In-spite of significantly correlated production due to baryon number, electric charge conservation and kinematical correlations of proto...

  6. Cumulants of multiplicity distributions in most central heavy ion collisions

    OpenAIRE

    Xu, Hao-jie

    2016-01-01

    We investigate the statistical expectations for cumulants of (net-conserved) charge distributions in relativistic heavy ion collisions, by including a simple but quantitatively more realistic geometric model, i.e. optical Glauber model. We suggest a new approach for centrality definition in studying of multiplicity fluctuations, which aim at eliminating the uncertainties between experimental measurements and theoretical calculations, as well as redoubling the statistics. We find that the stat...

  7. Fluctuating Glasma initial conditions and flow in heavy ion collisions

    OpenAIRE

    Schenke, Bjoern; Tribedy, Prithwish; Venugopalan, Raju

    2012-01-01

    We compute initial conditions in heavy-ion collisions within the Color Glass Condensate (CGC) framework by combining the impact parameter dependent saturation model (IP-Sat) with the classical Yang-Mills description of initial Glasma fields. In addition to fluctuations of nucleon positions, this IP-Glasma description includes quantum fluctuations of color charges on the length-scale determined by the inverse nuclear saturation scale Q_s. The model naturally produces initial energy fluctuation...

  8. Quark Recombination in Heavy Ion Collisions

    OpenAIRE

    Fries, Rainer J.(Cyclotron Institute, Department of Physics & Astronomy, Texas A&M University, College Station, TX, 77843-3366, USA)

    2011-01-01

    Data on high energy nuclear collisions collected at the Relativistic Heavy Ion Collider over the past decade have provided convincing evidence that hadronization is quite different in hot nuclear environments compared to p+p collisions. In particular, the data suggest that we see traces of quark degrees of freedom in elliptic flow, with the implication that collective flow is generated on the parton level and is transfered to hadrons through a simple recombination step. In this contribution w...

  9. Electronic excitation and charge transfer processes in collisions of H+, H2+, and H3+ ions with carbon monoxide at typical solar-wind velocities

    International Nuclear Information System (INIS)

    Luminescence in the 200-580 nm spectral region was observed in the collisions of H+, H2+, and H3+ with CO in the 50-1000 eV projectile energy range. Using computer simulations, we have identified emission of the following products in the observed spectra: the CO+(A-X) comet-tail system, CO+(B-X) first negative system, CO+(B-A) Baldet-Johnson system, and CO(b-a) third positive system. Also, an emission from atomic hydrogen (Hβ line at 486nm) has been observed. From the analysis of the experimental spectra, we have determined the absolute emission cross-sections for the formation of the observed products. Computer simulations gave the excited-product population distributions over vibrational and rotational energy levels. The vibrational level distribution from the CO+(A-X) comet-tail system is compared with the data for CO excited by 100 eV electrons and extreme ultraviolet radiation (XUV) photons. We have used these data to analyze the excitation conditions in the comet Humason (1961e). From the vibrational population distributions observed in the comet, we found that this distribution can be reproduced if electrons produce 25%, protons 70%, and XUV photons produce 5% of the emitting molecules. We find that the ratio of the CO+(B-X) emission to the sum of two main emissions (CO+(A-X)+CO+(B-X)) is velocity dependent and does not depend on the projectile ion type. For small velocities (below 100 km s–1) the ratio is about 5%, while for higher velocities it increases to 30%. For these data, we have found an empirical formula that satisfactorily describes the experimental data: R = R max(1 – v th/v), (where R max = 33%, v th = 87 km s–1). This could be used to infer the velocity of ions producing the observed emission of CO+ products.

  10. Vorticity in heavy-ion collisions

    Science.gov (United States)

    Deng, Wei-Tian; Huang, Xu-Guang

    2016-06-01

    We study the event-by-event generation of flow vorticity in the BNL Relativistic Heavy Ion Collider Au +Au collisions and CERN Large Hadron Collider Pb +Pb collisions by using the hijing model. Different definitions of the vorticity field and velocity field are considered. A variety of properties of the vorticity are explored, including the impact parameter dependence, the collision energy dependence, the spatial distribution, the event-by-event fluctuation of the magnitude and azimuthal direction, and the time evolution. In addition, the spatial distribution of the flow helicity is also studied.

  11. Elementary processes during collisions of ions with tryptophan molecules

    Science.gov (United States)

    Afrosimov, V. V.; Basalaev, A. A.; Kuz'michev, V. V.; Panov, M. N.; Smirnov, O. V.

    2016-03-01

    The relative cross sections of elementary processes occurring in single collisions of tryptophan molecules in the gaseous phase with He2+ ions with energy 4 keV/u are measured using time-of-flight mass spectrometry for studying the mechanism of radiation damage of amino acid molecules. The fragmentation channels for intermediate singly and doubly charged tryptophan molecular ions formed during one-electron capture, two-electron capture, and electron capture with ionization are investigated. Significant difference is observed in the mass spectra of fragmentation of intermediate doubly charged ions formed during the capture with ionization and double capture, which is associated with different energies of excitation of {C11H12N2O2}2+* ions.

  12. Electron-positron pair creation in heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Mai, Manuel [Physikalisches Institut, Universitaet Heidelberg (Germany)

    2011-07-01

    A theoretical description of highly charged ion collisions is given. At collision energies near the Coulomb barrier the formation of so quasi molecules can happen, with a ground state that dives into the ''Dirac sea'' at short distances of the ions. In that way an electron-positron pair can be created. For two ions traveling on classical Rutherford trajectories the two center Dirac equation is solved numerically with B-Splines. The solutions form a quasi complete set of basis functions at each instant of time. By means of coupled-channel calculations we perform the time evolution of the system, i.e. the transition from one basis set to another. Results are obtained in the monopole approximation in which only a monopole contribution of the potential is used in the Dirac equation.

  13. Dissipative heavy-ion collisions

    International Nuclear Information System (INIS)

    This report is a compilation of lecture notes of a series of lectures held at Argonne National Laboratory in October and November 1984. The lectures are a discussion of dissipative phenomena as observed in collisions of atomic nuclei. The model is based on a system which has initially zero temperature and the initial energy is kinetic and binding energy. Collisions excite the nuclei, and outgoing fragments or the compound system deexcite before they are detected. Brownian motion is used to introduce the concept of dissipation. The master equation and the Fokker-Planck equation are derived. 73 refs., 59 figs

  14. Production, transport and charge capture measurements of highly charged recoil ions

    International Nuclear Information System (INIS)

    An experiment is described to study highly charged recoil ions on-line to the heavy ion accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q=15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xeq+ for q=4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q=6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix. (orig.)

  15. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  16. Electron capture by highly charged ions from surfaces and gases

    International Nuclear Information System (INIS)

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar17+ and Ar18+ ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu-1, charge-selected and then decelerated down to 5 eVu-1 for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar17+ and Ar18+ ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu-1, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar16+ and Xe44+ and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  17. System size in relativistic heavy ion collisions

    Institute of Scientific and Technical Information of China (English)

    WANG Yang-Yang; ZHAO Lin-Jie; YUAN Zhong-Sheng; ZHANG Dan-Dan; FANG Wei; XU Ming-Mei

    2011-01-01

    System size is more than a geometrical quantity in relativistic heavy ion collisions; it is closely related to evolution process,i.e.a different system size corresponds to a different evolution process,and whether QGP is produced depends on the system size.We propose that the system size should be under the same level when comparing the measurements from different colliding nuclei.The equivalence of the peripheral collisions of Au-Au and the central collisions of smaller nuclei is studied using the Monte Carlo method.Comparing the transverse overlapping area of the colliding nuclei,the number of participant nucleons and the number of nucleon-nucleon binary collisions in various colliding nuclei,we give an estimate of the correspondence in system size.This is helpful in the experimental comparison of the measurements from different colliding nuclei.

  18. Study of relativistic heavy ion central collisions

    International Nuclear Information System (INIS)

    This thesis is devoted to the study of nuclear collisions between a target nucleus and a projectile nucleus, the latter having been accelerated at energies ranging from 100 to 2000 MeV (Mega-Electronvolts) per nucleon. The main goal of this field is the determination of nuclear matter equation of state at high densities and temperatures. This determination requires the study of central collisions only, that is collisions at small impact parameters. The detector ''Diogene'' used at the ''Saturne'' (Saclay, France) accelerator can measure simultaneously the momenta, masses and emission angles of all particles (pions, protons, deuterons ...) emitted in each collision. The pressure effects pre-dicted by the ''intra-nuclear cascade'' model are discussed. The pion (pi meson) production in relativistic heavy ion collisions is reviewed. Finally, we present the results of pion production measurements, using ''Diogene'', in collisions between alpha particles and carbon, copper, or lead target nuclei at 200, 400, 600 and 800 MeV per nucleon. The number of pions per collision is studied in relationship with the proton number. This can be explained in terms of compressional energy. The pion multiplicity distributions and the differential cross-sections are also presented

  19. Projectile energy loss in multiply ionizing ion-atom collisions

    International Nuclear Information System (INIS)

    The projectile energy loss for 7.5--25-MeV C6+,5+ and F6+ ions was measured for single collisions with He, Ne, Ar, and Kr as a function of the recoil-ion charge state and the projectile scattering. This energy loss was measured for collisions in which the projectile captured an electron and for those involving just direct ionization. We investigated and found a large average energy transfer (100--250 eV/electron) to the continuum electrons. A strong increase of the scattering angle with recoil-ion charge state was observed for both capture and direct ionization. The results imply that, for smaller impact parameters, higher recoil-ion charge states are produced and that higher energy losses are obtained. We observed a weak target-Z dependence of the energy loss. The results are compared with n-body classical-trajectory Monte Carlo calculations by Olson, semiclassical-approximation calculations by Schuch et al. [Nucl. Instrum. Methods Phys. Res. Sect. B 42, 566 (1989)], and the energy-deposition model

  20. Nonlinear QED Effects in Heavy Ion Collisions

    OpenAIRE

    Klein, Spencer R.

    2000-01-01

    Peripheral collisions of relativistic heavy ions uniquely probe many aspects of QED. Examples include $e^+e^-$ pair production and nuclear excitation in strong fields. After discussing these reactions, I will draw parallels between $\\gamma\\to e^+e^-$ and $\\gamma\\to q\\bar q$ and consider partly hadronic reactions. The scattered $q\\bar q$ pairs are a prolific source of vector mesons, which demonstrate many quantum effects. The two ions are a two-source interferometer, demonstrating interference...

  1. Chiral Magnetic Effect in Heavy Ion Collisions

    CERN Document Server

    Liao, Jinfeng

    2016-01-01

    The Chiral Magnetic Effect (CME) is a remarkable phenomenon that stems from highly nontrivial interplay of QCD chiral symmetry, axial anomaly, and gluonic topology. It is of fundamental importance to search for the CME in experiments. The heavy ion collisions provide a unique environment where a hot chiral-symmetric quark-gluon plasma is created, gluonic topological fluctuations generate chirality imbalance, and very strong magnetic fields $|\\vec{\\bf B}|\\sim m_\\pi^2$ are present during the early stage of such collisions. Significant efforts have been made to look for CME signals in heavy ion collision experiments. In this contribution we give a brief overview on the status of such efforts.

  2. Effect of Coulomb collision on the negative ion extraction mechanism in negative ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Goto, I., E-mail: goto@ppl.appi.keio.ac.jp; Nishioka, S.; Abe, S.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Mattei, S.; Lettry, J. [CERN, 1211 Geneva 23 (Switzerland)

    2016-02-15

    To improve the H{sup −} ion beam optics, it is necessary to understand the energy relaxation process of surface produced H{sup −} ions in the extraction region of Cs seeded H{sup −} ion sources. Coulomb collisions of charged particles have been introduced to the 2D3V-PIC (two dimension in real space and three dimension in velocity space particle-in-cell) model for the H{sup −} extraction by using the binary collision model. Due to Coulomb collision, the lower energy part of the ion energy distribution function of H{sup −} ions has been greatly increased. The mean kinetic energy of the surface produced H{sup −} ions has been reduced to 0.65 eV from 1.5 eV. It has been suggested that the beam optics of the extracted H{sup −} ion beam is strongly affected by the energy relaxation process due to Coulomb collision.

  3. Causal dissipative hydrodynamics for heavy ion collisions

    CERN Document Server

    Chaudhuri, A K

    2011-01-01

    We briefly discuss the recent developments in causal dissipative hydrodynamic for relativistic heavy ion collisions. Phenomenological estimate of QGP viscosity over entropy ratio from several experimental data, e.g. STAR's $\\phi$ meson data, centrality dependence of elliptic flow, universal scaling elliptic flow etc. are discussed. QGP viscosity, extracted from hydrodynamical model analysis can have very large systematic uncertainty due to uncertain initial conditions.

  4. Positron spectroscopy after heavy ion collisions

    International Nuclear Information System (INIS)

    The author reviews the theoretical and experimental results on positron production in heavy ion collisions. After a discussion of the quasi-atomic picture, the possible observation of the axion, and the inverse Bhabha scattering, the positron spectrometer EPOS of the GSI Darmstadt is described. Thereafter the experimental results are presented. (HSI)

  5. Quarkonium production in heavy-ion collisions

    Directory of Open Access Journals (Sweden)

    Arnaldi Roberta

    2014-03-01

    Full Text Available The production of quarkonium states plays a crucial role among the probes to investigate the formation of the plasma of quarks and gluons (QGP in heavy-ion collisions. A review of the charmonium and bottomonium production, mainly focussing on the latest results from the LHC experiments, is presented.

  6. Color screening in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    We calculate the color screening length in a non-equilibrated gluon gas formed by interacting minijets in relativistic heavy-ion collisions. We show that the screening length is too short at CERN LHC collider energy to permit the formation of independent flux-tubes or strings. The prediction for RHIC energies is somewhat ambiguous. (orig.)

  7. Relativistic Hydrodynamics for Heavy-Ion Collisions

    Science.gov (United States)

    Ollitrault, Jean-Yves

    2008-01-01

    Relativistic hydrodynamics is essential to our current understanding of nucleus-nucleus collisions at ultrarelativistic energies (current experiments at the Relativistic Heavy Ion Collider, forthcoming experiments at the CERN Large Hadron Collider). This is an introduction to relativistic hydrodynamics for graduate students. It includes a detailed…

  8. The quarkonium saga in heavy ion collisions

    CERN Document Server

    Tserruya, Itzhak

    2013-01-01

    J/psi suppression was proposed more than 25 years ago as an unambiguous signature for the formation of the Quark Gluon Plasma in relativistic heavy ion collisions. After intensive efforts, both experimental and theoretical, the quarkonium saga remains exciting, producing surprising results and not fully understood. This talk focuses on recent results on quarkonium production at RHIC and the LHC.

  9. Super high energy heavy ion collisions

    International Nuclear Information System (INIS)

    Basic theoretical ideas on a phase transition to a plasma of free quarks and gluons in heavy ion collisions are outlined. First results from experiments with oxygen beams at 14.5 GeV/c/N (BNL), 60 and 200 GeV/c/N (CERN) are discussed. 30 refs., 9 figs

  10. Sigma meson in heavy ion collision

    International Nuclear Information System (INIS)

    We want to present a short theoretical prediction of the behaviour of the sigma meson in heavy ion collisions. It is considered that the sigma meson is a pion-pion correlation, resulting from the decay of the N*(1440) resonance. There will be presented some QMD simulations. (authors)

  11. Charged kaon femtoscopic correlations in pp collisions at s=7TeV

    Science.gov (United States)

    Abelev, B.; Adam, J.; Adamová, D.; Adare, A. M.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agocs, A. G.; Agostinelli, A.; Ahammed, Z.; Ahmad, N.; Ahmad Masoodi, A.; Ahn, S. U.; Ahn, S. A.; Ajaz, M.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alici, A.; Alkin, A.; Almaráz Aviña, E.; Alme, J.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Anson, C.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arbor, N.; Arcelli, S.; Arend, A.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Asryan, A.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Äystö, J.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bailhache, R.; Bala, R.; Baldini Ferroli, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Bán, J.; Baral, R. C.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batyunya, B.; Baumann, C.; Bearden, I. G.; Beck, H.; Behera, N. K.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bergognon, A. A. E.; Berzano, D.; Betev, L.; Bhasin, A.; Bhati, A. K.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Bjelogrlic, S.; Blanco, F.; Blanco, F.; Blau, D.; Blume, C.; Boccioli, M.; Böttger, S.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bossú, F.; Botje, M.; Botta, E.; Braidot, E.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Browning, T. A.; Broz, M.; Brun, R.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calvo Villar, E.; Camerini, P.; Canoa Roman, V.; Cara Romeo, G.; Carena, F.; Carena, W.; Carlin Filho, N.; Carminati, F.; Casanova Díaz, A.; Castillo Castellanos, J.; Castillo Hernandez, J. F.; Casula, E. A. R.; Catanescu, V.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chawla, I.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Coccetti, F.; Colamaria, F.; Colella, D.; Collu, A.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contin, G.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortese, P.; Cortés Maldonado, I.; Cosentino, M. R.; Costa, F.; Cotallo, M. E.; Crescio, E.; Crochet, P.; Cruz Alaniz, E.; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dalsgaard, H. H.; Danu, A.; Das, S.; Das, I.; Das, D.; Das, K.; Dash, A.; Dash, S.; De, S.; de Barros, G. O. V.; De Caro, A.; de Cataldo, G.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; Delagrange, H.; Deloff, A.; De Marco, N.; Dénes, E.; De Pasquale, S.; Deppman, A.; D Erasmo, G.; de Rooij, R.; Diaz Corchero, M. A.; Di Bari, D.; Dietel, T.; Di Giglio, C.; Di Liberto, S.; Di Mauro, A.; Di Nezza, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Dönigus, B.; Dordic, O.; Driga, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Dutta Majumdar, M. R.; Elia, D.; Emschermann, D.; Engel, H.; Erazmus, B.; Erdal, H. A.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Eyyubova, G.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fearick, R.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feliciello, A.; Fenton-Olsen, B.; Feofilov, G.; Fernández Téllez, A.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floratos, E.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Garabatos, C.; Garcia-Solis, E.; Garishvili, I.; Gerhard, J.; Germain, M.; Geuna, C.; Gheata, M.; Gheata, A.; Ghosh, P.; Gianotti, P.; Girard, M. R.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez, R.; Ferreiro, E. G.; González-Trueba, L. H.; González-Zamora, P.; Gorbunov, S.; Goswami, A.; Gotovac, S.; Graczykowski, L. K.; Grajcarek, R.; Grelli, A.; Grigoras, C.; Grigoras, A.; Grigoriev, V.; Grigoryan, S.; Grigoryan, A.; Grinyov, B.; Grion, N.; Gros, P.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Guilbaud, M.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Han, B. H.; Hanratty, L. D.; Hansen, A.; Harmanová-Tóthová, Z.; Harris, J. W.; Hartig, M.; Harton, A.; Hasegan, D.; Hatzifotiadou, D.; Hayashi, S.; Hayrapetyan, A.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, N.; Hess, B. A.; Hetland, K. F.; Hicks, B.; Hippolyte, B.; Hori, Y.; Hristov, P.; Hřivnáčová, I.; Huang, M.; Humanic, T. J.; Hwang, D. S.; Ichou, R.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Incani, E.; Innocenti, G. M.; Innocenti, P. G.; Ippolitov, M.; Irfan, M.; Ivan, C.; Ivanov, V.; Ivanov, A.; Ivanov, M.; Ivanytskyi, O.; Jachołkowski, A.; Jacobs, P. M.; Jang, H. J.; Janik, M. A.; Janik, R.; Jayarathna, P. H. S. Y.; Jena, S.; Jha, D. M.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kaidalov, A. B.; Kalcher, S.; Kaliňák, P.; Kalliokoski, T.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kazantsev, A.; Kebschull, U.; Keidel, R.; Khan, M. M.; Khan, P.; Khan, K. H.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, S.; Kim, M.; Kim, M.; Kim, J. S.; Kim, J. H.; Kim, D. W.; Kim, B.; Kim, D. J.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kliemant, M.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kompaniets, M.; Kondratiev, V.; Kondratyeva, N.; Konevskikh, A.; Kour, R.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kramer, F.; Kravčáková, A.; Krawutschke, T.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Krus, M.; Kryshen, E.; Krzewicki, M.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kurashvili, P.; Kurepin, A. B.; Kurepin, A.; Kuryakin, A.; Kushpil, V.; Kushpil, S.; Kvaerno, H.; Kweon, M. J.; Kwon, Y.; Ladrón de Guevara, P.; Lakomov, I.; Langoy, R.; La Pointe, S. L.; Lara, C.; Lardeux, A.; La Rocca, P.; Lea, R.; Lechman, M.; Lee, G. R.; Lee, K. S.; Lee, S. C.; Legrand, I.; Lehnert, J.; Lenhardt, M.; Lenti, V.; León, H.; León Monzón, I.; León Vargas, H.; Lévai, P.; Li, S.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohner, D.; Loizides, C.; Loo, K. K.; Lopez, X.; López Torres, E.; Løvhøiden, G.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luo, J.; Luparello, G.; Luzzi, C.; Ma, K.; Ma, R.; Madagodahettige-Don, D. M.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Maire, A.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Mangotra, L.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez Davalos, A.; Martínez García, G.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matthews, Z. L.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mikhailov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitu, C.; Mizuno, S.; Mlynarz, J.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Monteno, M.; Montes, E.; Moon, T.; Morando, M.; Moreira De Godoy, D. A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Muhuri, S.; Mukherjee, M.; Müller, H.; Munhoz, M. G.; Musa, L.; Musinsky, J.; Musso, A.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Navin, S.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nicassio, M.; Niculescu, M.; Nielsen, B. S.; Niida, T.; Nikolaev, S.; Nikolic, V.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Nilsson, M. S.; Noferini, F.; Nomokonov, P.; Nooren, G.; Novitzky, N.; Nyanin, A.; Nyatha, A.; Nygaard, C.; Nystrand, J.; Ochirov, A.; Oeschler, H.; Oh, S. K.; Oh, S.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Ostrowski, P.; Otwinowski, J.; Oyama, K.; Ozawa, K.; Pachmayer, Y.; Pachr, M.; Padilla, F.; Pagano, P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S. K.; Palaha, A.; Palmeri, A.; Papikyan, V.; Pappalardo, G. S.; Park, W. J.; Passfeld, A.; Patalakha, D. I.; Paticchio, V.; Paul, B.; Pavlinov, A.; Pawlak, T.; Peitzmann, T.; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Perini, D.; Perrino, D.; Peryt, W.; Pesci, A.; Peskov, V.; Pestov, Y.; Petráček, V.; Petran, M.; Petris, M.; Petrov, P.; Petrovici, M.; Petta, C.; Piano, S.; Piccotti, A.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Pitz, N.; Piyarathna, D. B.; Planinic, M.; Płoskoń, M.; Pluta, J.; Pocheptsov, T.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polák, K.; Polichtchouk, B.; Pop, A.; Porteboeuf-Houssais, S.; Pospíšil, V.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Punin, V.; Putiš, M.; Putschke, J.; Quercigh, E.; Qvigstad, H.; Rachevski, A.; Rademakers, A.; Räihä, T. S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Ramírez Reyes, A.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riccati, L.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Rosnet, P.; Rossegger, S.; Rossi, A.; Roy, P.; Roy, C.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahoo, R.; Sahu, P. K.; Saini, J.; Sakaguchi, H.; Sakai, S.; Sakata, D.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Santoro, R.; Sarkamo, J.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, H. R.; Schmidt, C.; Schuchmann, S.; Schukraft, J.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, P. A.; Scott, R.; Segato, G.; Selyuzhenkov, I.; Senyukov, S.; Seo, J.; Serci, S.; Serradilla, E.; Sevcenco, A.; Shabetai, A.; Shabratova, G.; Shahoyan, R.; Sharma, S.; Sharma, N.; Rohni, S.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Sicking, E.; Siddhanta, S.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, T.; Sinha, B. C.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Smakal, R.; Smirnov, N.; Snellings, R. J. M.; Søgaard, C.; Soltz, R.; Son, H.; Song, M.; Song, J.; Soos, C.; Soramel, F.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A. P.; Subieta Vásquez, M. A.; Sugitate, T.; Suire, C.; Sultanov, R.; Šumbera, M.; Susa, T.; Symons, T. J. M.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szostak, A.; Szymański, M.; Takahashi, J.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tarazona Martinez, A.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Tlusty, D.; Toia, A.; Torii, H.; Toscano, L.; Trubnikov, V.; Truesdale, D.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ulery, J.; Ullaland, K.; Ulrich, J.; Uras, A.; Urbán, J.; Urciuoli, G. M.; Usai, G. L.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Vande Vyvre, P.; van Leeuwen, M.; Vannucci, L.; Vargas, A.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Venaruzzo, M.; Vercellin, E.; Vergara, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, Y.; Vinogradov, L.; Vinogradov, A.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Voloshin, K.; Voloshin, S.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, V.; Wagner, B.; Wan, R.; Wang, D.; Wang, M.; Wang, Y.; Wang, Y.; Watanabe, K.; Weber, M.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, A.; Wilk, G.; Williams, M. C. S.; Windelband, B.; Xaplanteris Karampatsos, L.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yoo, I.-K.; Yoon, J.; Yu, W.; Yuan, X.; Yushmanov, I.; Zaccolo, V.; Zach, C.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zelnicek, P.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhou, D.; Zhou, Y.; Zhou, F.; Zhu, J.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zinovjev, G.; Zoccarato, Y.; Zynovyev, M.; Zyzak, M.

    2013-03-01

    Correlations of two charged identical kaons (KchKch) are measured in pp collisions at s=7TeV by the ALICE experiment at the Large Hadron Collider (LHC). One-dimensional KchKch correlation functions are constructed in three multiplicity and four transverse momentum ranges. The KchKch femtoscopic source parameters R and λ are extracted. The KchKch correlations show a slight increase of femtoscopic radii with increasing multiplicity and a slight decrease of radii with increasing transverse momentum. These trends are similar to the ones observed for ππ and Ks0Ks0 correlations in pp and heavy-ion collisions. However at high multiplicities, there is an indication that the one-dimensional correlation radii for charged kaons are larger than those for pions in contrast to what was observed in heavy-ion collisions at the Relativistic Heavy-Ion Collider.

  12. Ion accumulation and space charge neutralization in intensive electron beams for ion sources and electron cooling

    International Nuclear Information System (INIS)

    The Electron Beam Ion Sources (EBIS), Electron Beam Ion Traps (EBIT) and electron beams for electron cooling application have the beam parameters in the same ranges of magnitudes. EBIS and EBIT produce and accumulate ions in the beam due to electron impact ionization. The cooling electron beam accumulates positive ions from the residual gas in the accelerator chamber during the cooling cycle. The space charge neutralization of cooling beam is also used to reduce the electron energy spread and enhance the cooling ability. The advanced results of experimental investigations and theoretical models of the EBIS electron beams are applied to analyze the problem of beam neutralization in the electron cooling techniques. The report presents the analysis of the most important processes connected with ion production, accumulation and losses in the intensive electron beams of ion sources and electron cooling systems for proton and ion colliders. The inelastic and elastic collision processes of charged particles in the electron beams are considered. The inelastic processes such as ionization, charge exchange and recombination change the charge states of ions and neutral atoms in the beam. The elastic Coulomb collisions change the energy of particles and cause the energy redistribution among components in the electron-ion beams. The characteristic times and specific features of ionization, beam neutralization, ion heating and loss in the ion sources and electron cooling beams are determined. The dependence of negative potential in the beam cross section on neutralization factor is studied. 17 refs., 5 figs., 1 tab

  13. Fragmentation of CO2 molecules in slow charge exchange collisions with Ar8+

    International Nuclear Information System (INIS)

    Charge exchange collisions between multiply charged ions and CO2 have been studied at low collision velocities (E=400 eV/amu). The stability of the ion, produced in different charge states, is analyzed by means of a time-of-flight spectrometer. Recoil ions and fragments are measured in coincidence with projectile ions, which are selected with respect to their charge state and the scattering angle. For large impact parameters the production of singly and doubly charged CO2 ions turns out to be the major process. The opening of one out of two molecular bindings is found to be more likely than the total fragmentation of the molecule. The formation of O+ and CO+ fragments with very small kinetic energies is explained by single electron capture forming CO2+ in the excited (C 2Σg+) state. Collisions with smaller impact parameters and multi-electron capture processes always lead to a total fragmentation of the molecule characterized by a symmetric Coulomb explosion

  14. Particle production in heavy ion collisions

    International Nuclear Information System (INIS)

    The status of thermal model descriptions of particle production in heavy ion collisions is presented. We discuss the formulation of statistical models with different implementation of the conservation laws and indicate their applicability in heavy ion and elementary particle collisions. We analyze experimental data on hadronic abundances obtained in ultra-relativistic heavy ion collisions, in a very broad energy range starting from RHIC/BNL (√(s) = 200 A GeV), SPS/CERN (√(s) ≅ 20 A GeV) up to AGS/BNL (√(s) ≅ 5 A GeV) and SIS/GSI (√(s) ≅ 2 A GeV) to test equilibration of the fireball created in the collision. We argue that the statistical approach provides a very satisfactory description of experimental data covering this wide energy range. Any deviations of the model predictions from the data are indicated. We discuss the unified description of particle chemical freeze-out and the excitation functions of different particle species. At SPS and RHIC energy the relation of freeze-out parameters with the QCD phase boundary is analyzed. Furthermore, the application of the extended statistical model to quantitative understanding of open and hidden charm hadron yields is considered. (orig.)

  15. Electron capture by highly charged low-velocity ions

    International Nuclear Information System (INIS)

    This paper describes the use of a fast heavy ion beam to produce, by bombardment of gaseous targets, highly-charged low-velocity recoil ions, and the use of these secondary ions in turn as projectiles in studies of electron capture and ionization in low-energy collision systems. The interest in collisions involving low-energy highly-charged projectiles comes both from the somewhat simplifying aspects of the physics which attend the long-range capture and from applications to fusion plasmas, astrophysics and more speculative technology such as the production of X-ray lasers. The ions of interest in such applications should have both electronic excitation and center-of-mass energies in the keV range and cannot be produced by simply stripping fast heavy ion beams. Several novel types of ion source have been developed to produce low-energy highly-charged ions, of which the secondary ion recoil source discussed in this paper is one. (Auth.)

  16. Beam-Energy Dependence of Charge Balance Functions from Au+Au Collisions at RHIC

    OpenAIRE

    STAR Collaboration

    2015-01-01

    Balance functions have been measured in terms of relative pseudorapidity ($\\Delta \\eta$) for charged particle pairs at the Relativistic Heavy-Ion Collider (RHIC) from Au+Au collisions at $\\sqrt{s_{\\rm NN}}$ = 7.7 GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the Large Hadron Collider (LHC) from Pb+Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions beco...

  17. Cross sections for ion-molecular reactions in hydrogen systems and for charge transfer reactions of slow multiply charged ions

    International Nuclear Information System (INIS)

    Cross sections of ion-molecular reactions in hydrogen systems of H+-H2, H2+-H2 and H3+-H2 and charge transfer cross sections of multiply charged ions in atomic and molecular targets are presented in graphs and tables of the part A, B and C. All data presented for 99 collision systems have been measured systematically using an octo-pole ion beam guide (OPIG) technique till now since 1985. The part A is for ion-molecular reactions in hydrogen systems. In the lower energy region below few eV in center-of-mass systems, it is seen obviously at a glance that the ion-molecular reaction in hydrogen systems is dominated by H3+ formation process. In the energy region from few eV to few hundred eV in center-of-mass systems, many reaction channels of decay processes from intermediate molecular states seem to be opened resonantly. Some of cross section data in the part B for charge transfer reactions of low-charged ions produced by a conventional electron impact type (Nier type) ion source should be noted to strongly depend on the electron impact energy due to contamination of low lying metastable states in projectile ions. The part C is for charge transfer reactions of multiply charged ions extracted from a small type of electron beam ion source (Mini-EBIS). In measurements using the mini-EBIS, no evidence of metastable ions existing in the primary ion beam has been found except for doubly charged ion beam. The higher energy end of the present cross sections are connected with previous data in fairly good

  18. Solar Wind Charge Exchange Studies Of Highly Charged Ions On Atomic Hydrogen

    International Nuclear Information System (INIS)

    Accurate studies of low-energy charge exchange (CX) are critical to understanding underlying soft X-ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H-like, and He-like ions of C, N, O and Ne, which are the dominant charge states for these heavier elements in the solar wind. Absolute total cross sections for single electron capture by H-like ions of C, N, O and fully-stripped O ions from atomic hydrogen have been measured in an expanded range of relative collision energies (5 eV/u-20 keV/u) and compared to previous H-oven measurements. The present measurements are performed using a merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source installed on a high voltage platform at the Oak Ridge National Laboratory. For the collision energy range of 0.3 keV/u-3.3 keV/u, which corresponds to typical ion velocities in the solar wind, the new measurements are in good agreement with previous H-oven measurements. The experimental results are discussed in detail and compared with theoretical calculations where available.

  19. Collisions of antiprotons with hydrogen molecular ions

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2009-01-01

    method are applied in order to describe the target molecule and the collision process. It is shown that three perpendicular orientations of the molecular axis with respect to the trajectory are sufficient to accurately reproduce the ionization cross section calculated by Sakimoto [Phys. Rev. A 71, 062704......Time-dependent close-coupling calculations of the ionization and excitation cross section for antiproton collisions with molecular hydrogen ions are performed in an impact energy range from 0.5 keV to 10 MeV. The Born-Oppenheimer and Franck-Condon approximations as well as the impact parameter...... (2005)] reducing the numerical effort drastically. The independent-event model is employed to approximate the cross section for double ionization and H+ production in antiproton collisions with H2....

  20. Bose—Einstein correlations of charged kaons in p + p collisions with the STAR detector

    Science.gov (United States)

    Nigmatkulov, Grigory

    2016-01-01

    We report the results of charged kaon Bose-Einstein Correlations (BEC) measured in proton- proton collisions at √s =200 and 510 GeV with the STAR detector at Relativistic Heavy Ion Collider (RHIC). The one-dimensional correlation functions are studied as a function of the charged particle multiplicity. The femtoscopic radii, R, and the correlation strength, λ, are extracted. The dependence of the source radii and the correlation strengths on the particle multiplicity are investigated.

  1. Charged kaon femtoscopic correlations in pp collisions at $\\sqrt{s}=7$ TeV

    CERN Document Server

    Abelev, B; Adamova, D; Adare, A M; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agocs, A G; Agostinelli, A; Ahammed, Z; Ahmad, N; Ahmad Masoodi, A; Ahn, S U; Ahn, S A; Ajaz, M; Akindinov, A; Aleksandrov, D; Alessandro, B; Alici, A; Alkin, A; Almaraz Avina, E; Alme, J; Alt, T; Altini, V; Altinpinar, S; Altsybeev, I; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Anson, C; Anticic, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshauser, H; Arbor, N; Arcelli, S; Arend, A; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Asryan, A; Augustinus, A; Averbeck, R; Awes, T C; Aysto, J; Azmi, M D; Bach, M; Badala, A; Baek, Y W; Bailhache, R; Bala, R; Baldini Ferroli, R.; Baldisseri, A; Baltasar Dos Santos Pedrosa, F; Ban, J; Baral, R C; Barbera, R; Barile, F; Barnafoldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batyunya, B; Baumann, C; Bearden, I G; Beck, H; Behera, N K; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; 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Chawla, I; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Chochula, P; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Coccetti, F; Colamaria, F; Colella, D; Collu, A; Conesa Balbastre, G; Conesa del Valle, Z; Connors, M E; Contin, G; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortese, P; Cortes Maldonado, I; Cosentino, M R; Costa, F; Cotallo, M E; Crescio, E; Crochet, P; Cruz Alaniz, E; Cuautle, E; Cunqueiro, L; Dainese, A; Dalsgaard, H H; Danu, A; Das, S; Das, I; Das, D; Das, K; Dash, A; Dash, S; De, S; de Barros, G O V; De Caro, A; De Cataldo, G; de Cuveland, J; De Falco, A; De Gruttola, D; Delagrange, H; Deloff, A; De Marco, N; Denes, E; De Pasquale, S; Deppman, A; D'Erasmo, G; de Rooij, R; Diaz Corchero, M A; Di Bari, D; Dietel, T; Di Giglio, C; Di Liberto, S; Di Mauro, A; Di Nezza, P; Divia, R; Djuvsland, O; Dobrin, A; Dobrowolski, T; Donigus, B; Dordic, O; Driga, O; Dubey, A K; Dubla, A; Ducroux, L; Dupieux, P; Dutta Majumdar, A K; Dutta Majumdar, M R; Elia, D; Emschermann, D; Engel, H; Erazmus, B; Erdal, H A; Espagnon, B; Estienne, M; Esumi, S; Evans, D; Eyyubova, G; Fabris, D; Faivre, J; Falchieri, D; Fantoni, A; Fasel, M; Fearick, R; Fehlker, D; Feldkamp, L; Felea, D; Feliciello, A; Fenton-Olsen, B; Feofilov, G; Fernandez Tellez, A; Ferretti, A; Festanti, A; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Floratos, E; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Frankenfeld, U; Fuchs, U; Furget, C; Fusco Girard, M; Gaardhoje, J J; Gagliardi, M; Gago, A; Gallio, M; Gangadharan, D R; Ganoti, P; Garabatos, C; Garcia-Solis, E; Garishvili, I; Gerhard, J; Germain, M; Geuna, C; Gheata, M; Gheata, A; Ghosh, P; Gianotti, P; Girard, M R; Giubellino, P; Gladysz-Dziadus, E; Glassel, P; Gomez, R; Ferreiro, E G; Gonzalez-Trueba, L H; Gonzalez-Zamora, P; Gorbunov, S; Goswami, A; 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Jimenez Bustamante, R T; Jones, P G; Jung, H; Jusko, A; Kaidalov, A B; Kalcher, S; Kalinak, P; Kalliokoski, T; Kalweit, A; Kang, J H; Kaplin, V; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karpechev, E; Kazantsev, A; Kebschull, U; Keidel, R; Khan, M M; Khan, P; Khan, K H; Khan, S A; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, S; Kim, M; Kim, M; Kim, J S; Kim, J H; Kim, D W; Kim, B; Kim, D J; Kim, T; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Klay, J L; Klein, J; Klein-Bosing, C; Kliemant, M; Kluge, A; Knichel, M L; Knospe, A G; Kohler, M K; Kollegger, T; Kolojvari, A; Kompaniets, M; Kondratiev, V; Kondratyeva, N; Konevskikh, A; Kour, R; Kovalenko, V; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kral, J; Kralik, I; Kramer, F; Kravcakova, A; Krawutschke, T; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Krus, M; Kryshen, E; Krzewicki, M; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kurashvili, P; Kurepin, A B; Kurepin, A; Kuryakin, A; Kushpil, V; Kushpil, S; Kvaerno, H; Kweon, M J; Kwon, Y; Ladron de Guevara, P; Lakomov, I; Langoy, R; La Pointe, S L; Lara, C; Lardeux, A; La Rocca, P; Lea, R; Lechman, M; Lee, G R; Lee, K S; Lee, S C; Legrand, I; Lehnert, J; Lenhardt, M; Lenti, V; Leon, H; Leon Monzon, I; Leon Vargas, H; Levai, P; Li, S; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Ljunggren, H M; Loenne, P I; Loggins, V R; Loginov, V; Lohner, D; Loizides, C; Loo, K K; Lopez, X; Lopez Torres, E; Lovhoiden, G; Lu, X G; Luettig, P; Lunardon, M; Luo, J; Luparello, G; Luzzi, C; Ma, K; Ma, R; Madagodahettige-Don, D M; Maevskaya, A; Mager, M; Mahapatra, D P; Maire, A; Malaev, M; Maldonado Cervantes, I; Malinina, L; Mal'Kevich, D; Malzacher, P; Mamonov, A; Manceau, L; Mangotra, L; Manko, V; Manso, F; Manzari, V; Mao, Y; Marchisone, M; Mares, J; Margagliotti, G V; Margotti, A; Marin, A; Markert, C; Marquard, M; Martashvili, I; Martin, N A; Martinengo, P; Martinez, M I; Martinez Davalos, A; Martinez Garcia, G; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastroserio, A; Matthews, Z L; Matyja, A; Mayer, C; Mazer, J; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Mercado Perez, J; Meres, M; Miake, Y; Mikhailov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miskowiec, D; Mitu, C; Mizuno, S; Mlynarz, J; Mohanty, B; Molnar, L; Montano Zetina, L; Monteno, M; Montes, E; Moon, T; Morando, M; Moreira De Godoy, D A; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Muhuri, S; Mukherjee, M; Muller, H; Munhoz, M G; Musa, L; Musinsky, J; Musso, A; Nandi, B K; Nania, R; Nappi, E; Nattrass, C; Navin, S; Nayak, T K; Nazarenko, S; Nedosekin, A; Nicassio, M; Niculescu, M; Nielsen, B S; Niida, T; Nikolaev, S; Nikolic, V; Nikulin, S; Nikulin, V; Nilsen, B S; Nilsson, M S; Noferini, F; Nomokonov, P; Nooren, G; Novitzky, N; Nyanin, A; Nyatha, A; Nygaard, C; Nystrand, J; Ochirov, A; Oeschler, H; Oh, S K; Oh, S; Oleniacz, J; Oliveira Da Silva, A C; Oppedisano, C; Ortiz Velasquez, A; Oskarsson, A; Ostrowski, P; Otwinowski, J; Oyama, K; Ozawa, K; Pachmayer, Y; Pachr, M; Padilla, F; Pagano, P; Paic, G; Painke, F; Pajares, C; Pal, S K; Palaha, A; Palmeri, A; Papikyan, V; Pappalardo, G S; Park, W J; Passfeld, A; Pastircak, B; Patalakha, D I; Paticchio, V; Paul, B; Pavlinov, A; Pawlak, T; Peitzmann, T; Pereira Da Costa, H; Pereira De Oliveira Filho, E; Peresunko, D; Perez Lara, C E; Perini, D; Perrino, D; Peryt, W; Pesci, A; Peskov, V; Pestov, Y; Petracek, V; Petran, M; Petris, M; Petrov, P; Petrovici, M; Petta, C; Piano, S; Piccotti, A; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Pitz, N; Piyarathna, D B; Planinic, M; Ploskon, M; Pluta, J; Pocheptsov, T; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Polak, K; Polichtchouk, B; Pop, A; Porteboeuf-Houssais, S; Pospisil, V; Potukuchi, B; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puddu, G; Punin, V; Putis, M; Putschke, J; Quercigh, E; Qvigstad, H; Rachevski, A; Rademakers, A; Raiha, T S; Rak, J; Rakotozafindrabe, A; Ramello, L; Ramirez Reyes, A; Raniwala, R; Raniwala, S; Rasanen, S S; Rascanu, B T; Rathee, D; Read, K F; Real, J S; Redlich, K; Reed, R J; Rehman, A; Reichelt, P; Reicher, M; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J P; Reygers, K; Riccati, L; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Rodriguez Cahuantzi, M; Rodriguez Manso, A; Roed, K; Rohr, D; Rohrich, D; Romita, R; Ronchetti, F; Rosnet, P; Rossegger, S; Rossi, A; Roy, P; Roy, C; Rubio Montero, A J; Rui, R; Russo, R; Ryabinkin, E; Rybicki, A; Sadovsky, S; Safarik, K; Sahoo, R; Sahu, P K; Saini, J; Sakaguchi, H; Sakai, S; Sakata, D; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Sanchez Castro, X; Sandor, L; Sandoval, A; Sano, M; Santagati, G; Santoro, R; Sarkamo, J; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, H R; Schmidt, C; Schuchmann, S; Schukraft, J; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, P A; Scott, R; Segato, G; Selyuzhenkov, I; Senyukov, S; Seo, J; Serci, S; Serradilla, E; Sevcenco, A; Shabetai, A; Shabratova, G; Shahoyan, R; Sharma, S; Sharma, N; Rohni, S; Shigaki, K; Shtejer, K; Sibiriak, Y; Sicking, E; Siddhanta, S; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Simonetti, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, T; Sinha, B C; Sitar, B; Sitta, M; Skaali, T B; Skjerdal, K; Smakal, R; Smirnov, N; Snellings, R J M; Sogaard, C; Soltz, R; Son, H; Song, M; Song, J; Soos, C; Soramel, F; Sputowska, I; Spyropoulou-Stassinaki, M; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Stolpovskiy, M; Strmen, P; Suaide, A A P; Subieta Vasquez, M A; Sugitate, T; Suire, C; Sultanov, R; Sumbera, M; Susa, T; Symons, T J M; Szanto de Toledo, A; Szarka, I; Szczepankiewicz, A; Szostak, A; Szymanski, M; Takahashi, J; Tapia Takaki, J D; Tarantola Peloni, A.; Tarazona Martinez, A; Tauro, A; Tejeda Munoz, G; Telesca, A; Terrevoli, C; Thader, J; Thomas, D; Tieulent, R; Timmins, A R; Tlusty, D; Toia, A; Torii, H; Toscano, L; Trubnikov, V; Truesdale, D; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ulery, J; Ullaland, K; Ulrich, J; Uras, A; Urban, J; Urciuoli, G M; Usai, G L; Vajzer, M; Vala, M; Valencia Palomo, L; Vallero, S; Vande Vyvre, P; van Leeuwen, M; Vannucci, L; Vargas, A; Varma, R; Vasileiou, M; Vasiliev, A; Vechernin, V; Veldhoen, M; Venaruzzo, M; Vercellin, E; Vergara, S; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, Y; Vinogradov, L; Vinogradov, A; Virgili, T; Viyogi, Y P; Vodopyanov, A; Voloshin, K; Voloshin, S; Volpe, G; von Haller, B; Vorobyev, I; Vranic, D; Vrlakova, J; Vulpescu, B; Vyushin, A; Wagner, V; Wagner, B; Wan, R; Wang, D; Wang, M; Wang, Y; Wang, Y; Watanabe, K; Weber, M; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, A; Wilk, G; Williams, M C S; Windelband, B; Xaplanteris Karampatsos, L; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, S; Yasnopolskiy, S; Yi, J; Yin, Z; Yoo, I K; Yoon, J; Yu, W; Yuan, X; Yushmanov, I; Zaccolo, V; Zach, C; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Zavada, P; Zaviyalov, N; Zbroszczyk, H; Zelnicek, P; Zgura, I S; Zhalov, M; Zhang, H; Zhang, X; Zhou, D; Zhou, Y; Zhou, F; Zhu, J; Zhu, H; Zhu, J; Zhu, X; Zichichi, A; Zimmermann, A; Zinovjev, G; Zoccarato, Y; Zynovyev, M; Zyzak, M

    2013-01-01

    Correlations of two charged identical kaons (K$^{ch}$ K$^{ch}$) are measured in pp collisions at $\\sqrt{s}$=7 TeV by the ALICE experiment at the Large Hadron Collider (LHC). One-dimensional K$^{ch}$ K$^{ch}$ correlation functions are constructed in three multiplicity and four transverse momentum ranges. The K$^{ch}$ K$^{ch}$ femtoscopic source parameters R and lambda are extracted. The K$^{ch}$ K$^{ch}$ correlations show a slight increase of femtoscopic radii with increasing multiplicity and a slight decrease of radii with increasing transverse momentum. These trends are similar to the ones observed for $\\pi\\pi$ and $K_s^0 K_s^0$ correlations in pp and heavy-ion collisions. However, the observed one dimensional correlation radii for charged kaons are larger at high multiplicities than those for pions in contrast to what was observed in heavy-ion collisions at RHIC.

  2. Femtoscopy in Relativistic Heavy Ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Lisa, M; Pratt, S; Soltz, R A; Wiedemann, U

    2005-07-29

    Analyses of two-particle correlations have provided the chief means for determining spatio-temporal characteristics of relativistic heavy ion collisions. We discuss the theoretical formalism behind these studies and the experimental methods used in carrying them out. Recent results from RHIC are put into context in a systematic review of correlation measurements performed over the past two decades. The current understanding of these results are discussed in terms of model comparisons and overall trends.

  3. Hydrodynamics and relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    The hydrodynamic model as applied to heavy-ion collisions is introduced. The Euler equations are derived for both relativistic and non-relativistic domains. The effects of imposing relativistic invariance are discussed. Concepts proposed to analyze 4π exclusive reactions are introduced. Selected theoretical results are presented for reactions in which the projectile has a laboratory energy of 400 MeV per nucleon to 100 GeV per nucleon

  4. Glueballs in Peripheral Heavy-Ion Collisions

    OpenAIRE

    A.A. Natale

    1995-01-01

    We estimate the cross-section for glueball production in peripheral heavy-ion collisions through two-photon and double-Pomeron exchange, at energies that will be available at RHIC and LHC. Glueballs will be produced at large rates, opening the possibility to study decays with very small branching ratios. In particular, we discuss the possibility of observing the subprocess $\\gamma \\gamma (PP) \\rightarrow G \\rightarrow \\gamma \\gamma$.

  5. Hubble flow in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Experiments at the RHIC and LHC can recreate quark-gluon plasma conditions similar to those when the Universe was less than a few microseconds old, and will offer the best prospects to discover how the Universe evolved in early stages. In this work we study the (anti)deuteron-to-(anti)proton ratio obtained in heavy ion collisions at relativistic energies and compare the results with the ratio obtained from Big Bang nucleosynthesis.

  6. Commissioning of the DESIREE storage rings – a new facility for cold ion-ion collisions

    International Nuclear Information System (INIS)

    We report on the ongoing commissioning of the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. Beams of atomic carbon anions (C−) and smaller carbon anion molecules (C−2, C−3, C−4 etc.) have been produced in a sputter ion source, accelerated to 10 keV or 20 keV, and stored successfully in the two electrostatic rings. The rings are enclosed in a common vacuum chamber cooled to below 13 Kelvin. The DESIREE facility allows for studies of internally relaxed single isolated atomic, molecular and cluster ions and for collision experiments between cat- and anions down to very low center-of-mass collision energies (meV scale). The total thermal load of the vacuum chamber at this temperature is measured to be 32 W. The decay rates of stored ion beams have two components: a non-exponential component caused by the space charge of the beam itself which dominates at early times and an exponential term from the neutralization of the beam in collisions with residual gas at later times. The residual gas limited storage lifetime of carbon anions in the symmetric ring is over seven minutes while the 1/e lifetime in the asymmetric ring is measured to be about 30 seconds. Although we aim to improve the storage in the second ring, the number of stored ions are now sufficient for many merged beams experiments with positive and negative ions requiring milliseconds to seconds ion storage

  7. Jets in Heavy Ion Collisions with CMS

    CERN Document Server

    Salur, Sevil

    2016-01-01

    Jet physics in heavy ion collisions is a rich field which has been rapidly evolving since the first observations of medium interactions at RHIC through back-to-back hadron correlations and at LHC via reconstructed jets. In order to completely characterize the final state via jet-medium interactions and distinguish between competing energy loss mechanisms complementary and robust jet observables are investigated. Latest developments of jet finding techniques and their applications to heavy ion environments are discussed with an emphasis given on experimental results from CMS experiment.

  8. Behavior of Charge Fluctuations in Relativistic Nucleus-nucleus Collisions

    Institute of Scientific and Technical Information of China (English)

    SA; Ben-hao; TAI; An

    2002-01-01

    Using a hadron and string cascade model JPCIAE, we have investigated the dependence ofevent-by-event charge fluctuations on (pseudo)rapidity window size, final state interaction, resonancedecay, centrality, and reaction energy for Pb + Pb collisions at SPS and LHC energies and for Au + Aucollisions at RHIC energies. The JPCIAE results of the charge fluctuations as a function of rapidity

  9. Laser sources of multiply charged heavy ions

    International Nuclear Information System (INIS)

    Laser production of highly charged ions is studied at the 50 J photodissociation iodine laser facility PERUN. The laser beam is focused onto various metallic targets. The use of a parabolic mirror with a hole in the center instead of a focusing lens allows for measuring ion beam parameters along the laser beam axis and results in two fold increase in the ion extraction. The diagnostics of the laser-produced ions in a far expansion zone is based on the time-of-flight method. The reported results prove the existence of highly charged ions with ion charge z > 40 in a far expansion zone and their survival during the recombination processes occurring in early stages of expansion. The higher laser power density is applied the higher ion charge states are generated. The maximum ion charge achieved e.g. for tantalum was z = 55. (J.U.)

  10. Kinetic energy release in CO fragmentation by electron loss and capture collisions of fast B''2''+ ions

    International Nuclear Information System (INIS)

    Ionization and fragmentation of CO molecules have been investigated in charge-changing collisions of B''2''+ ions at v = 1.69 a.u.. Fragment ions from CO were measured by using a momentum 3D imaging technique in coincidence with outgoing projectile charge states. We deduced the kinetic energy release (KER) associated with charge-changing collisions of B''2''+ to B''3''+, B''1''+ and B''0''+. The KER spectra in the fragmentation to C''+ and O''+ ions are found to be different to some extent for these loss and capture collisions. It is concluded that the electron loss collision populates the intact CO molecule to highly excited states of (CO)''2''+''1 more effectively than electron capture collisions, resulting from different effective impact parameters associated with loss and capture collisions.

  11. Collision of low energy Na+ ion with C60

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The collision-induced reaction of Na+ ion with neutral C6o vapour was investigated at the energy range of 10 to 150 eV. The deposited films were studied via laser desorption time-of-flight mass spectroscopy (TOFMS). The fragment products of C60 with even number of carbon atoms, such as Cn+ (n=58, 56, 54), and adduct products, such as Cn+ (n=62, 64, 66, 68) were obser.vcd in the positively charged TOF mass spectra. The endohedral fullerene ion of Na@C60+ was detected when collision energies are above 20 eV. Besides, no negative endohedral fullerene was detected, the products appearing in positively charged mass spectra were also observed in the negatively charged mass spectra. In addition, a series of products with odd number of carbon atoms, such as Cn- (n=53, 55, 57, 59, 61, 63, 65, 67), also appeared, but the intensities of their signals were not as high as that of even numbered. Finally, it is interesting to find that the deposited films are insoluable in toluene, benzene or water. Their Fourier transform infrared (FTIR) spectra seem like those photopolymerized ones. Some of the reaction schemes are proposed to explain the experimental results.

  12. Study of Light Ion Collisions

    CERN Multimedia

    2002-01-01

    Inelastic and elastic pd, dd, p@a and @a@a interactions are studied at a nucleon-nucleon cm energy @]s^n^n = 31~GeV using the Split-Field-Magnet detector. The two forward telescopes have been upgraded by two calorimeters to tag spectator neutrons and by two MWPCs for improved detection of charged nuclear fragments. Several selective triggers are planned in addition to the minimum-bias trigger: 1) high p^t single hadron at 10|0, 20|0 and 45|0; 2) central particle production together with unfragmented projectiles; 3) nuclear break-up without particle production; 4) elastic interactions. This experiment is an extension of the @a-run in 1980; the new one will benefit from the direct comparisons of @a@a, dd, @ap and dp interactions; from expected higher integrated luminosity for @a@a interactions; the upgrading of the spectator tagging capability and the new high p^t triggers installed by R41

  13. Propagation of Ion-Acoustic Wave in an Inhomogeneous Dusty Plasma with. Dust Charge Fluctuation

    Institute of Scientific and Technical Information of China (English)

    LI Jing-Ju; XIAO De-Long; LI Yang-Fang; MA Jin-Xiu

    2007-01-01

    @@ The propagation of dust ion-acoustic wave in an inhomogeneous dusty plasma is studied by taking the dust charge fluctuation and collisions into account. It is shown that the dust charge fluctuation brings a phase shift to the wave. Furthermore, because of the presence of dust charge fluctuation, a new damping term rises, which makes the damping more sharply.

  14. Soft vs Hard: Particle Production in High-Energy Heavy-Ion Collisions

    CERN Document Server

    Mishra, Aditya Nath; Pareek, Pooja; Behera, Nirbhay K; Sahoo, Raghunath; Nandi, Basanta K

    2015-01-01

    The centrality dependence of pseudorapidity density of charged particles and transverse energy is studied for a wide range of collision energies for heavy-ion collisions at midrapidity. A two-component model approach has been adopted to quantify the soft and hard components of particle production, coming from nucleon participants and binary nucleon-nucleon collisions, respectively. Within experimental uncertainties, the hard component contributing to the particle production has been found to be nearly independent of collisions energy from RHIC to LHC. The suppression of high-$p_{\\rm T}$ hadrons and jets in the medium created in heavy-ion collisions seem to play a role in the nearly independent collision energy behavior of hard components in particle production. We also use MC event generators, like HIJING and AMPT to study the possible effects of the suppression of high $p_{T}$ partons inside the medium and the effect of the threshold momentum for minijets, contributing to hard scattering processes.

  15. Direct photons in heavy-ion collisions

    International Nuclear Information System (INIS)

    Direct photon emission from heavy-ion collisions has been calculated and compared to available experimental data. Three different models have been combined to extract direct photons from different environments in a heavy-ion collision: Thermal photons from partonic and hadronic matter have been extracted from relativistic, non-viscous 3+1-dimensional hydrodynamic calculations. Thermal and non-thermal photons from hadronic interactions have been calculated from relativistic transport theory. The impact of different physics assumptions about the thermalized matter has been studied. The models used for the determination of photons from both hydrodynamic and transport calculations have been elucidated and their numerical properties tested. The origin of direct photons, itemised by emission stage, emission time, channel and baryon number density, has been investigated for various systems, as have the transverse momentum spectra and elliptic flow patterns of direct photons. Taking into account the full (vacuum) spectral function of the rho-meson decreases the direct photon emission by approximately 10% at low photon transverse momentum. In all systems that have been considered -- heavy-ion collisions at Elab=35 AGeV and 158 AGeV, (sNN)1/2=62.4 GeV, 130 GeV and 200 GeV -- thermal emission from a system with partonic degrees of freedom is greatly enhanced over that from hadronic systems, while the difference between the direct photon yields from a viscous and a non-viscous hadronic system (transport vs. hydrodynamics) is found to be very small. Predictions for direct photon emission in central U+U-collisions at 35 AGeV have been made. (orig.)

  16. Direct photons in heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Baeuchle, Bjoern

    2010-12-13

    Direct photon emission from heavy-ion collisions has been calculated and compared to available experimental data. Three different models have been combined to extract direct photons from different environments in a heavy-ion collision: Thermal photons from partonic and hadronic matter have been extracted from relativistic, non-viscous 3+1-dimensional hydrodynamic calculations. Thermal and non-thermal photons from hadronic interactions have been calculated from relativistic transport theory. The impact of different physics assumptions about the thermalized matter has been studied. The models used for the determination of photons from both hydrodynamic and transport calculations have been elucidated and their numerical properties tested. The origin of direct photons, itemised by emission stage, emission time, channel and baryon number density, has been investigated for various systems, as have the transverse momentum spectra and elliptic flow patterns of direct photons. Taking into account the full (vacuum) spectral function of the rho-meson decreases the direct photon emission by approximately 10% at low photon transverse momentum. In all systems that have been considered -- heavy-ion collisions at E{sub lab}=35 AGeV and 158 AGeV, (s{sub NN}){sup 1/2}=62.4 GeV, 130 GeV and 200 GeV -- thermal emission from a system with partonic degrees of freedom is greatly enhanced over that from hadronic systems, while the difference between the direct photon yields from a viscous and a non-viscous hadronic system (transport vs. hydrodynamics) is found to be very small. Predictions for direct photon emission in central U+U-collisions at 35 AGeV have been made. (orig.)

  17. Study of flow in asymmetric heavy-ion collisions

    International Nuclear Information System (INIS)

    Azimuthal anisotropy is a key tool to study the strongly interacting medium produced in relativistic heavy ion collisions. This observable is sensitive to the equation of state of the system formed in the heavy-ion collisions. Recently, it has been proposed at the Relativistic Heavy Ion Collider, to carry out a program of asymmetric heavy-ion collisions. Among other physics possibilities, it is believed to provide insight on the initial conditions through study of event-by-event fluctuation in the measure of the azimuthal anisotropy. Knowing the initial condition is vital for any theoretical calculations in relativistic heavy-ion collisions

  18. Estimation of electric conductivity of the quark gluon plasma via asymmetric heavy-ion collisions

    OpenAIRE

    Hirono, Yuji(Department of Physics, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan); Hongo, Masaru; Hirano, Tetsufumi

    2012-01-01

    We show that in asymmetric heavy-ion collisions, especially off-central Cu+Au collisions, a sizable strength of electric field directed from Au nucleus to Cu nucleus is generated in the overlapping region, because of the difference in the number of electric charges between the two nuclei. This electric field would induce an electric current in the matter created after the collision, which result in a dipole deformation of the charge distribution. The directed flow parameters $v_1^{\\pm}$ of ch...

  19. Hard scattering contribution to particle production in high energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Global observables like the multiplicity of produced charged particles and transverse energy, are the key observables used to characterize the properties of the matter created in heavy-ion collisions. In order to study the dependence of the charged particle density on colliding system, center of mass energy and collision centrality, there have been measurements starting few GeV to TeV energies at LHC. There is a need to understand the particle production contribution coming from the QCD hard processes, which scale with number of binary nucleon-nucleon collisions, Ncoll and soft processes scaling with number of participant nucleons, Npart

  20. Rearrangement reactions in ion-ion and ion-atom collisions: results and problems

    Energy Technology Data Exchange (ETDEWEB)

    Presnyakov, L.P. [Lebedev Physical Institute, Moscow (Russian Federation); Tawara, H.

    1997-01-01

    Recent experimental and theoretical results are discussed for ionic collisions with large cross sections at intermediate and small energies of the relative motion. Single- and double-electron removal from H{sup -} ions in slow collisions with other ions is considered in more details. The theoretical methods are discussed from the viewpoint of general requirements of scattering theory. (author)

  1. Dissipative processes in light heavy ion collisions

    International Nuclear Information System (INIS)

    The deep inelastic processes in light heavy ion collisions were systematically studied in the reactions 19 F(111.4, 125, 136.9 MeV) + 12 C, 27 Al, and 27 Al(140.14 MeV) + 12 C, 27 Al using the experimental device DRACULA mounted at LNS-Catania. ΔE - E identification, continuous measurements of energy and angle, mass identification by time-of-flight and γ-multiplicity measurements have been performed for the main reaction products. The double differential cross sections, as a function of different experimental observables, show similar trends with those observed for much heavier systems. Thus, a complete dynamics, from quasielastic to complete dissipation regime, is evidenced even in the case of such light systems and microscopic models could be described. The variance of the charge distribution and the amount of energy dissipated per exchanged nucleon for light systems follow the same type of correlations as medium and heavy systems which have been explained within very simple hypotheses. The interaction time, estimated from the experimental angular distributions for different windows of total kinetic energy, varies from some units of 10-23 sec up to the order of 10-21 sec, showing the presence of fast and slow processes relative to the transit time value of ∼ 5·10-22 sec. The increasing value of the interaction time, represented as a function of the atomic number (Z) and total kinetic energy loss, shows that isotopes with atomic numbers farther from the projectile corresponding value can be populated. Thus, integrated angular distributions usually presented in the literature, becoming flatter with increasing number of transferred nucleons, reflect the necessity of a larger interaction time in order to reach products very different from the projectile. For the same degree of inelasticity of the reaction, the estimated mean lifetime is roughly the same for every atomic number value in the exit channel. This suggests a diffusion-type process. After describing

  2. Pionic instabilities in high-energy heavy ion collisions

    International Nuclear Information System (INIS)

    The study of heavy ion reactions includes the determination of whether pionic instabilities can exist at the densities and excitation energies expected in heavy ion collisions, the calculation of growth rates of unstable pion modes, and the determination of the effect such instabilities would have on the dynamics in heavy ion collisions. 14 references

  3. Temporal evolution of ion energy distribution functions and ion charge states of Cr and Cr-Al pulsed arc plasmas

    International Nuclear Information System (INIS)

    To study the temporal evolution of ion energy distribution functions, charge-state-resolved ion energy distribution functions of pulsed arc plasmas from Cr and Cr-Al cathodes were recorded with high time resolution by using direct data acquisition from a combined energy and mass analyzer. The authors find increases in intensities of singly charged ions, which is evidence that charge exchange reactions took place in both Cr and Cr-Al systems. In Cr-Al plasmas, the distributions of high-charge-state ions exhibit high energy tails 50 μs after discharge ignition, but no such tails were observed at 500 μs. The energy ratios of ions of different charge states at the beginning of the pulse, when less neutral atoms were in the space in front of the cathode, suggest that ions are accelerated by an electric field. The situation is not so clear after 50 μs due to particle collisions. The initial mean ion charge state of Cr was about the same in Cr and in Cr-Al plasmas, but it decreased more rapidly in Cr-Al plasmas compared to the decay in Cr plasma. The faster decay of the mean ion charge state and ion energy caused by the addition of Al into a pure Cr cathode suggests that the mean ion charge state is determined not only by ionization processes at the cathode spot but also by inelastic collision between different elements

  4. Temporal evolution of ion energy distribution functions and ion charge states of Cr and Cr-Al pulsed arc plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Koichi, E-mail: tanak@mmc.co.jp [Central Research Institute, Mitsubishi Materials Corporation, 1002-14 Mukohyama, Naka-shi, Ibaraki 311-0102 (Japan); Anders, André [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 53, Berkeley, California 94720 (United States)

    2015-11-15

    To study the temporal evolution of ion energy distribution functions, charge-state-resolved ion energy distribution functions of pulsed arc plasmas from Cr and Cr-Al cathodes were recorded with high time resolution by using direct data acquisition from a combined energy and mass analyzer. The authors find increases in intensities of singly charged ions, which is evidence that charge exchange reactions took place in both Cr and Cr-Al systems. In Cr-Al plasmas, the distributions of high-charge-state ions exhibit high energy tails 50 μs after discharge ignition, but no such tails were observed at 500 μs. The energy ratios of ions of different charge states at the beginning of the pulse, when less neutral atoms were in the space in front of the cathode, suggest that ions are accelerated by an electric field. The situation is not so clear after 50 μs due to particle collisions. The initial mean ion charge state of Cr was about the same in Cr and in Cr-Al plasmas, but it decreased more rapidly in Cr-Al plasmas compared to the decay in Cr plasma. The faster decay of the mean ion charge state and ion energy caused by the addition of Al into a pure Cr cathode suggests that the mean ion charge state is determined not only by ionization processes at the cathode spot but also by inelastic collision between different elements.

  5. A space charge compensation model for positive DC ion beams

    International Nuclear Information System (INIS)

    In this paper, we revisit and extend a formula to predict the compensation of space charge in positive DC ion beams of non-relativistic energy, as they are for example found in the injector beam lines of heavy ion accelerator facilities.The original formula was presented in 1975 by Igor Gabovich et al. and takes into account the de-compensation through Coulomb collisions of the primary beam ions and the compensating electrons. We extend its usability to arbitrary (positive) charge states of the ions and non-quasineutral beams.The resulting formula compares well with measurements using a retarding field analyzer and a multi-species generalization of it was incorporated into beam transport simulations using the particle-in-cell code WARP

  6. Charged-Particle Multiplicity in Proton-Proton Collisions

    CERN Document Server

    Grosse-Oetringhaus, Jan Fiete

    2010-01-01

    This article summarizes and critically reviews measurements of charged-particle multiplicity distributions and pseudorapidity densities in p+p(pbar) collisions between sqrt(s) = 23.6 GeV and sqrt(s) = 1.8 TeV. Related theoretical concepts are briefly introduced. Moments of multiplicity distributions are presented as a function of sqrt(s). Feynman scaling, KNO scaling, as well as the description of multiplicity distributions with a single negative binomial distribution and with combinations of two or more negative binomial distributions are discussed. Moreover, similarities between the energy dependence of charged-particle multiplicities in p+p(pbar) and e+e- collisions are studied. Finally, various predictions for pseudorapidity densities, average multiplicities in full phase space, and multiplicity distributions of charged particles in p+p(pbar) collisions at the LHC energies of sqrt(s) = 7 TeV, 10 TeV, and 14 TeV are summarized and compared.

  7. Influence of the density of states on the odd-even staggering in the charge distribution of the emitted fragments in nuclear heavy-ion collisions

    Science.gov (United States)

    Calleya, N. L.; Souza, S. R.; Carlson, B. V.; Donangelo, R.; Lynch, W. G.; Tsang, M. B.; Winkelbauer, J. R.

    2014-11-01

    The fragmentation of thermalized sources is studied using a version of the Statistical Multifragmentation Model which employs state densities that take the pairing gap in the nuclear levels into account. Attention is focused on the properties of the charge distributions observed in the breakup of the source. Since the microcanonical version of the model used in this study provides the primary fragment excitation energy distribution, one may correlate the reduction of the odd-even staggering in the charge distribution with the increasing occupation of high-energy states. Thus, in the framework of this model, such staggering tends to disappear as a function of the total excitation energy of the source, although the energy per particle may be small for large systems. We also find that, although the deexcitation of the primary fragments should, in principle, blur these odd-even effects as the fragments follow their decay chains, the consistent treatment of pairing may significantly enhance these staggering effects on the final yields. In the framework of this model, we find that odd-even effects in the charge distributions should be observed in the fragmentation of relatively light systems at very low excitation energies. Our results also suggest that the odd-even staggering may provide useful information on the nuclear state density.

  8. Multifragmentation and dynamics in heavy ion collisions

    Indian Academy of Sciences (India)

    R Roy

    2001-07-01

    A midrapidity zone formed in heavy-ion collisions has been investigated through special selections of light particles and intermediate mass fragments detected in the reaction 35Cl on 12C at 43 MeV/nucleon and the reactions 58Ni on 12C, 24Mg, and 197Au at 34.5 MeV/nucleon, and of neutron energy spectra measured in the reaction 35Cl on natTa. Properties of the observables have been examined to characterize the neck-like structure formed between the two reaction partners.

  9. HBT in Relativisitic Heavy Ion Collisions

    OpenAIRE

    Murray, Michael

    2001-01-01

    A summary of current interferometry data in relativistic heavy ions is presented. At sqrt{s}=17GeV a sudden increase in the pion source volume is observed for central PbPb collisions. This seems to imply that the pion phase density has reached a limit. The source size of different particles decreases with mass when the transverse velocity is held constant but increases with mass when the transverse mass is held constant. The antiproton source radius is larger than the proton source radius. So...

  10. Jet Reconstruction in Heavy Ion Collisions

    CERN Document Server

    Cacciari, Matteo; Salam, Gavin P; Soyez, Gregory

    2011-01-01

    We examine the problem of jet reconstruction at heavy-ion colliders using jet-area-based background subtraction tools as provided by FastJet. We use Monte Carlo simulations with and without quenching to study the performance of several jet algorithms, including the option of filtering, under conditions corresponding to RHIC and LHC collisions. We find that most standard algorithms perform well, though the anti-kt and filtered Cambridge/Aachen algorithms have clear advantages in terms of the reconstructed transverse-momentum offset and dispersion.

  11. Diomega production in relativistic heavy ion collisions

    OpenAIRE

    Pal, Subrata; Ko, C. M.; Zhang, Z. Y.

    2001-01-01

    Using a multiphase transport model, we study the production of a new strange dibaryon (\\Omega\\Omega)_{0+} in dense hadronic matter formed in relativistic heavy ion collisions. The (multi-)strange baryons (\\Xi and \\Omega) are produced by strangeness-exchange reactions between antikaons and hyperons in the pure hadronic phase. The rescattering between the omegas at midrapidity leads to a production probability of \\simeq 3x10^{-7} (\\Omega\\Omega)_{0+} per event at the RHIC energy of \\sqrt s=130A ...

  12. Mass Spectra and Ion Collision Cross Sections of Hemoglobin

    Science.gov (United States)

    Kang, Yang; Terrier, Peran; Douglas, D. J.

    2011-02-01

    Mass spectra of commercially obtained hemoglobin (Hb) show higher levels of monomer and dimer ions, heme-deficient dimer ions, and apo-monomer ions than hemoglobin freshly prepared from blood. This has previously been attributed to oxidation of commercial Hb. Further, it has been reported that that dimer ions from commercial bovine Hb have lower collision cross sections than low charge state monomer ions. To investigate these effects further, we have recorded mass spectra of fresh human Hb, commercial human and bovine Hb, fresh human Hb oxidized with H2O2, lyophilized fresh human Hb, fresh human Hb both lyophilized and chemically oxidized, and commercial human Hb oxidized with H2O2. Masses of α-monomer ions of all hemoglobins agree with the masses expected from the sequences within 3 Da or better. Mass spectra of the β chains of commercial Hb and oxidized fresh human Hb show a peak or shoulder on the high mass side, consistent with oxidation of the protein. Both commercial proteins and oxidized fresh human Hb produce heme-deficient dimers with masses 32 Da greater than expected and higher levels of monomer and dimer ions than fresh Hb. Lyophilization or oxidation of Hb both produce higher levels of monomer and dimer ions in mass spectra. Fresh human Hb, commercial human Hb, commercial bovine Hb, and oxidized commercial human Hb all give dimer ions with cross sections greater than monomer ions. Thus, neither oxidation of Hb or the difference in sequence between human and bovine Hb make substantial differences to cross sections of ions.

  13. Theory of ion-atom collisions at high energy, I

    International Nuclear Information System (INIS)

    Electron capture process by an ion from a neutral atom is one of the fundamental problems in the theory of atomic collision physics. Here a brief review is given mainly on the processes of non-radiative and radiative electron capture (charge transfer and REC). The main mechanism which govern the charge transfer process is introduced and the characteristic feature which is predicted by the theory is explained. As for the radiative electron capture process, after introducting the present theories, the full-quantum mechanical theoretical treatment is introduced. The theory leads a result which includes some inconsistency with formulae obtained by guage transformation. The relativistic quantum mechanical treatment is being tried in order to remove this inconsistency. The some results including mass and velocity dependence are reported and discussed. (author)

  14. Transfer ionization of the isocharge sequence ion and Ar collisions

    Institute of Scientific and Technical Information of China (English)

    Cai Xiao-Hong; Yu De-Yang; Cao Zhu-Rong; Lu Rong-Chun; Yang Wei; Shao Cao-Jie; Chen Xi-Meng

    2004-01-01

    The ratios of transfer ionization to single capture for isocharge Cq+, Nq+, Oq+, Neq+ ions on Ar atoms are measured by using position-sensitive and time-of-flight techniques. It is found that the ratio R1 increases with nuclear charge Z in a q=4 sequence, and the ratio R1 sequences have the minimum values at Z=7 and Z=8 in q=5 and q=6 sequences, respectively, and the ratio R1 decreases with the increase in the nuclear charge Z in a q=7 sequence. The results may be explained within the frame of the statistical model. It may be concluded that the transfer ionization depends remarkably upon the electronic structure of the projectile. The projectiles used in this study have the same charge state and velocity, but different electronic structures. The dependence of the ratio R1 on q is studied for Neq+-Ar collisions. The ratio R1 is found to increase as q increases for Neq+-Ar collisions. The measured dependence of the ratio R1 on q is compared with the calculation using the molecular Coulomb over-barrier model.

  15. Study on space charge compensation in negative hydrogen ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, A. L.; Chen, J. E. [University of Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2016-02-15

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H{sup +} beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H{sup −} beam from a 2.45 GHz microwave driven H{sup −} ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  16. Study on space charge compensation in negative hydrogen ion beam

    Science.gov (United States)

    Zhang, A. L.; Peng, S. X.; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y.; Chen, J. E.

    2016-02-01

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H+ beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H- beam from a 2.45 GHz microwave driven H- ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  17. Study on space charge compensation in negative hydrogen ion beam

    International Nuclear Information System (INIS)

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H+ beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H− beam from a 2.45 GHz microwave driven H− ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results

  18. Heavy-ion collisions at high energy

    International Nuclear Information System (INIS)

    Relativistic heavy ion collisions are studied here taking into account the hard scattering model of Schmidt and Blankenbecler along with a dynamical derivation of the inclusive distribution for pp→πx, pp→Kx, and pp→p-barx and pp→px proposed in an earlier paper. This scheme takes into account scale breaking and it is found that both A and B dependence occur in such processes as AB→π-x, AB→K-barx, AB→p-barx, and AB→px in the forward region. In the backward region the independent N-N collision model is also found satisfactory when the structural rearrangement factor is incorporated in the vertex function. It is found that although in the forward region scale breaking is not appreciable, it becomes quite significant in the backward region. The x distributions in the forward region as well as in the backward region have been computed on the basis of this independent N-N collision model. The results are found to be in very good agreement for inclusive pion production

  19. Neutral-particle emission in collisions of electrons with biomolecular ions in an electrostatic storage ring

    International Nuclear Information System (INIS)

    Electron-biomolecular ion collisions were studied using an electrostatic storage ring with a merging electron beam device. Biomolecular ions produced by an electrospray ion source and accelerated to 20 keV/charge were injected into the ring after being mass-analyzed. The circulating ion beam was then merged with an electron beam. Neutral reaction products in collisions of electrons with ions were detected by a micro-channel plate outside of the ring. Electron-ion collisions were studied for multiply-deprotonated oligonucleotide and peptide anions as well as singly protonated oligonucleotide and peptide cations. For peptide cations, neutrals were resonantly emitted at an electron energy of around 6.5 eV, which was almost independent of the ion masses. This is deduced to come from electron-ion recombination, resulting in the cleavage of a peptide bond. For DNA oligonucleotide cations, resonant neutral particle emission was also observed. In electron and DNA anion collisions, neutrals started to increase from definite threshold energies, where the threshold energies increased in proportion to the ion charge. The same was found for peptide anions. The origin of this phenomenon is discussed

  20. Impact of high energy heavy ion nuclear collisions on advancement of nuclear physics

    International Nuclear Information System (INIS)

    The contributions of low energy heavy ion research to the inventions in nuclear physics are highlighted. The theoretical ideas used in their interpretations are qualitatively discussed. The survey of the literature relevant to charged particle spectroscopy and reactions with heavy ions is presented. The light projectile collision work and its relevant physics is also briefly summarized. In light of this, few suggestions are made to effectively use our heavy ion facilities. (author). 4 refs

  1. Electromagnetic pair production in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    We survey the phenomenon of pair production by the transient electromagnetic fields produced in relativistic heavy-ion collisions, as it impinges upon atomic, nuclear, and particle physics, and the design of accelerators and detectors. The subject is naturally divided between coherent production in peripheral collisions, and incoherent production in central collisions. We discuss examples illustrating both regimes

  2. Total and differential cross sections for charge transfer in He2+-He+ collisions: trajectory effects

    International Nuclear Information System (INIS)

    Cross sections have been computed for charge transfer in collisions between 4He+ and 4He2+ ions for centre-of-mass collision energies 0.21 ≤ E ≤ 2.50 keV. The semi-classical impact parameter method was employed, with a basis of atomic orbitals modified by plane-wave translation factors. Both rectilinear and Coulomb trajectories were used, and the differential cross sections were found to be sensitive to the assumed form of trajectory. Comparison is made with molecular orbital calculations by previous workers. (author)

  3. Relativistic, QED and nuclear effects in highly charged ions revealed by resonant electron-ion recombination in storage rings

    OpenAIRE

    Schippers, Stefan

    2008-01-01

    Dielectronic recombination (DR) of few-electron ions has evolved into a sensitive spectroscopic tool for highly charged ions. This is due to technological advances in electron-beam preparation and ion-beam cooling techniques at heavy-ion storage rings. Recent experiments prove unambiguously that DR collision spectroscopy has become sensitive to 2nd order QED and to nuclear effects. This review discusses the most recent developments in high-resolution spectroscopy of low-energy DR resonances, ...

  4. Charge-dependent azimuthal correlation measurements in Pb-Pb collisions with ALICE

    International Nuclear Information System (INIS)

    Parity violation in strong interactions is predicted to be observable in relativistic heavy-ion collisions. The occurrence of parity-odd domains may result in charge separation along a strong magnetic field created by moving ions - a phenomenon dubbed the chiral magnetic effect (CME). Sensitive experimental observables include two particle azimuthal correlations and correlation of particle pairs relative to the reaction plane. A challenge is to separate contributions to these correlations from background sources, which include local charge conservation and initial density fluctuations. Correlations for lead-lead collisions at sNN=√(2.76) TeV measured with the ALICE detector are presented as a function of centrality, average and relative transverse momentum, and separation in pseudorapidity, providing additional constraints for models.

  5. Fast ion-atom and ion-molecule collisions

    CERN Document Server

    2013-01-01

    The principal goal of this book is to provide state-of-the art coverage of the non-relativistic three- and four-body theories at intermediate and high energy ion-atom and ion-molecule collisions. The focus is on the most frequently studied processes: electron capture, ionization, transfer excitation and transfer ionization. The content is suitable both for graduate students and experienced researchers. For these collisions, the literature has seen enormous renewal of activity in the development and applications of quantum-mechanical theories. This subject is of relevance in several branches of science and technology, like accelerator-based physics, the search for new sources of energy and high temperature fusion of light ions. Other important applications are in life sciences via medicine, where high-energy ion beams are used in radiotherapy for which a number of storage ring accelerators are in full operation, under construction or planned to be built worldwide. Therefore, it is necessary to review this fiel...

  6. Ion slowing down and charge exchange at small impact parameters selected by channeling: superdensity effects

    OpenAIRE

    L'Hoir, A.; Adoui, A.; Barrué, F.; Billebaud, A.; Bosch, F.; Bräuning-Demian, A.; Bräuning, H.; Cassimi, A.; Chevallier, M.; C. Cohen; Dauvergne, D; Demonchy, C.E.; Giot, L.; Kirsch, R.; Gumberidze, A

    2005-01-01

    In two experiments performed with 20-30 MeV/u highly charged heavy ions (Pb56+, U91+) channeled through thin silicon crystals, we observed the original features of superdensity, associated to the glancing collisions with atomic rows undergone by part of the incident projectiles. In particular the very high collision rate yields a quite specific charge exchange regime, that leads to a higher ionization probability than in random conditions. X-ray measurements show that electrons captured in ou...

  7. Studying Heavy Ion Collisions Using Methods From Cosmic Microwave Background (CMB) Analysis

    Science.gov (United States)

    Gaardhøje, J. J.; Tabassam, H.

    2014-04-01

    We present and discuss a framework for studying the morphology of high-multiplicity events from relativistic heavy ion collisions using methods commonly employed in the analysis of the photons from the Cosmic Microwave Background (CMB). The analysis is based on the decomposition of the distribution of the number density of (charged) particles expressed in polar and azimuthal coordinates into a sum of spherical harmonic functions. We present an application of the method exploting relevant symmetries to the study of azimuthal correlations arizing from collective flow among charged particles produced in relativistic heavy ion collisions. We discuss perspectives for event-by- event analyses, which with increasing collision energy will eventually open entirely new dimensions in the study of ultrarelaticistic heavy ion reactions.

  8. Studying Heavy Ion Collisions Using Methods From Cosmic Microwave Background (CMB Analysis

    Directory of Open Access Journals (Sweden)

    Gaardhøje J. J.

    2014-04-01

    Full Text Available We present and discuss a framework for studying the morphology of high-multiplicity events from relativistic heavy ion collisions using methods commonly employed in the analysis of the photons from the Cosmic Microwave Background (CMB. The analysis is based on the decomposition of the distribution of the number density of (charged particles expressed in polar and azimuthal coordinates into a sum of spherical harmonic functions. We present an application of the method exploting relevant symmetries to the study of azimuthal correlations arizing from collective flow among charged particles produced in relativistic heavy ion collisions. We discuss perspectives for event-by- event analyses, which with increasing collision energy will eventually open entirely new dimensions in the study of ultrarelaticistic heavy ion reactions.

  9. Dynamic screening and wake effects on electronic excitation in ion-solid and ion-surface collisions

    International Nuclear Information System (INIS)

    The collective electronic response in a solid effectively alters ionic and atomic potentials giving rise to dynamic screening and to a ''wake'' of density fluctuations trailing ions as they propagate through the solid. The presence of dynamic screening modifies electronic excitation processes of projectiles in ion-solid collisions as compared to binary ion-atom collisions. We review recent theoretical and experimental studies directed at the search for and identification of signatures of dynamic screening and wake effects. Examples include the formation of excited projectile bound states under channeling conditions, radiative electron capture, the search for ''wake riding'' electrons in antiproton-solid collisions, and the neutralization of highly charged ions near surfaces. 42 refs., 7 figs

  10. Landau quantization effects in ultracold atom-ion collisions

    Science.gov (United States)

    Simoni, Andrea; Launay, Jean-Michel

    2011-12-01

    We study ultracold atom-ion collisions in the presence of an external magnetic field. At low collision energy the field can drastically modify the translational motion of the ion, which follows quantized cyclotron orbits. We present a rigorous theoretical approach for the calculation of quantum scattering amplitudes in these conditions. Collisions in different magnetic field regimes, identified by the size of the cyclotron radius with respect to the range of the interaction potential, are investigated. Our results are important in cases where use of a magnetic field to control the atom-ion collision dynamics is envisioned.

  11. Landau quantization effects in ultracold atom-ion collisions

    International Nuclear Information System (INIS)

    We study ultracold atom-ion collisions in the presence of an external magnetic field. At low collision energy the field can drastically modify the translational motion of the ion, which follows quantized cyclotron orbits. We present a rigorous theoretical approach for the calculation of quantum scattering amplitudes in these conditions. Collisions in different magnetic field regimes, identified by the size of the cyclotron radius with respect to the range of the interaction potential, are investigated. Our results are important in cases where use of a magnetic field to control the atom-ion collision dynamics is envisioned.

  12. Production and physics of highly charged ions

    International Nuclear Information System (INIS)

    Highly charged ions with very few electrons make a novel and attractive research object in atomic physics. High precision spectroscopy of such ions provides a powerful tool for exploring relativistic and quantum electrodynamic effects. Moreover, their enormous electro static potential gives rise to conspicuous effects during their interaction with other particles or matters. Study of the highly charged ions may thus open up a hitherto unexplored realm of physics, shedding light on giant resonance due to multi-hole states, multiply-excited resonances displaying strong electron correlations, etc. While this comprehensive study of highly charged ions is aimed at contributing to fundamental science, spinoff should contribute to such areas as the X-ray laser, nuclear fusion and space science. In spite of their importance, it is not easy to produce these ions. Various laboratory sources are being developed. Among these, the Electron Beam Ion Source (EBIS) and the Electron Cyclotron Beam Ion Source (ECRIS) are the powerful ones and have the potential to produce ions of higher charge state, keeping the ion energy low. Our purpose here is both to summarize briefly the current state of the development for highly charged ion source, and to introduce a part of atomic physics experiments with the source. (author)

  13. Radiation emission in electron-tungsten ions collisions: Polarization vs static channels

    Energy Technology Data Exchange (ETDEWEB)

    Astapenko, V.A., E-mail: v.a.astapenko@gmail.com [Moscow Institute of Physics and Technology (Russian Federation); Lisitsa, V.S., E-mail: lisitsa@nfi.kiae.ru [RSC ' Kurchatov Institute' (Russian Federation); Rosmej, F.B., E-mail: frank.rosmej@upmc.fr [Universite Pierre et Marie Curie, LULI, Paris (France)

    2011-06-13

    The detailed comparison between static (frozen core) and polarization radiation emission channel in electron-tungsten ions collisions is presented. Both Bremsstrahlung and radiative recombination spectra are calculated for different ion charges Z{sub i} and electron energies E. The consideration is based on quasiclassical approach using statistical (Thomas-Fermi) and local plasma frequency models for ion cores as well as rotational approximation for emission spectra. The frequency and energy domains where polarization channel is comparable or even dominates over static one are determined. The results are of interest for modern magnetic fusion investigations of plasmas with tungsten impurity. -- Highlights: → Static and polarization radiation in electron-tungsten ions collisions is investigated. → Both Bremsstrahlung and radiative recombination spectra are calculated. → Different ion charges and electron energies are taken into consideration. → We determine the ranges of parameters where polarization channel is important.

  14. Quarkonia at finite temperature in relativistic heavy-ion collisions

    Indian Academy of Sciences (India)

    Saumen Datta

    2015-05-01

    The behaviour of quarkonia in relativistic heavy-ion collisions is reviewed. After a detailed discussion of the current theoretical understanding of quarkonia in a static equilibriated plasma, we discuss quarkonia yield from the fireball created in ultrarelativistic heavy-ion collision experiments. We end with a brief discussion of the experimental results and outlook.

  15. Bremsstrahlung Pair Production In Relativistic Heavy Ion Collision

    OpenAIRE

    Meier, H; Hencken, K.; Trautmann, D.; Baur, G.

    1997-01-01

    We calculate production of electron- and muon-pairs by the bremsstrahlung process in hadron collisions and compare it with the dominant two-photon process. Results for the total cross section are given for proton-proton and heavy-ion collisions at energies of the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC).

  16. Landau quantization effects in ultracold atom-ion collisions

    OpenAIRE

    Simoni, Andrea; Launay, Jean-Michel

    2011-01-01

    We study ultracold atom-ion collisions in the presence of an external magnetic field. At low collision energy the field can drastically modify the translational motion of the ion, which follows quantized cyclotron orbits. We present a rigorous theoretical approach for the calculation of quantum scattering amplitudes in these conditions. Collisions in different magnetic field regimes, identified by the size of the cyclotron radius with respect to the range of the interaction potential, are inv...

  17. Experimental study of the fragmentation of water clusters induced by multiply charged ions

    OpenAIRE

    Maisonny, Rémi

    2011-01-01

    This work deals with the fragmentation of neutral water clusters induced by collisions with slow and swift multiply charged ions. Strong projectile charge dependence is found for all of the fragmentation patterns in the charge transfer regime. When increasing the projectile charge (from q = 2 to q = 20), we observe a modification of the scenario of the fragmentation dynamics with a transition from a partial dissociation to a full cluster explosion. We observe that water clusters are more stro...

  18. Interaction of low-energy highly charged ions with matter

    International Nuclear Information System (INIS)

    The thesis presented herein deals with experimental studies of the interaction between highly charged ions and neutral matter at low collision energies. The energy range investigated is of great interest for the understanding of both charge exchange reactions between ions comprising the solar wind and various astrophysical gases, as well as the creation of near-surface nanostructures. Over the course of this thesis an experimental setup was constructed, capable of reducing the kinetic energy of incoming ions by two orders of magnitude and finally focussing the decelerated ion beam onto a solid or gaseous target. A coincidence method was employed for the simultaneous detection of photons emitted during the charge exchange process together with the corresponding projectile ions. In this manner, it was possible to separate reaction channels, whose superposition presumably propagated large uncertainties and systematic errors in previous measurements. This work has unveiled unexpectedly strong contributions of slow radiative decay channels and clear evidence of previously only postulated decay processes in charge exchange-induced X-ray spectra. (orig.)

  19. Dipolar degrees of freedom and Isospin equilibration processes in Heavy Ion collisions

    CERN Document Server

    Papa, M; Acosta, L; Amorini, F; Agodi, C; Anzalone, A; Auditore, L; Cardella, G; Cavallaro, S; Chatterjee, M B; De Filippo, E; Francalanza, L; Geraci, E; Grassi, L; Gnoffo, B; Han, J; La Guidara, E; Lanzalone, G; Lombardo, I; Pagano, C Maiolino T Minniti A; Pagano, E V; Pirrone, S; Politi, G; Porto, F; Quattrocchi, L; Rizzo, F; Rosato, E; Russotto, P; Trifirò, A; Trimarchi, M; Verde, G; Vigilante, and M

    2015-01-01

    Background: In heavy ion collision at the Fermi energies Isospin equilibration processes occur- ring when nuclei with different charge/mass asymmetries interacts have been investigated to get information on the nucleon-nucleon Iso-vectorial effective interaction. Purpose: In this paper, for the system 48Ca +27 Al at 40 MeV/nucleon, we investigate on this process by means of an observable tightly linked to isospin equilibration processes and sensitive in exclusive way to the dynamical stage of the collision. From the comparison with dynamical model calculations we want also to obtain information on the Iso-vectorial effective microscopic interaction. Method: The average time derivative of the total dipole associated to the relative motion of all emitted charged particles and fragments has been determined from the measured charges and velocities by using the 4? multi-detector CHIMERA. The average has been determined for semi- peripheral collisions and for different charges Zb of the biggest produced fragment. E...

  20. Chemical Property in Heavy Ion Collisions

    Science.gov (United States)

    Kaneta, M.

    K-/K+ and bar{p}/p ratios measured in 158 A\\cdotGeV Pb + Pb collisions are shown as a function of centrality and transverse momentum (Pt). Little significant centrality dependence in neither K-/K+ nor bar{p}/p ratios are observed and they are almost constant as a function of Pt. The chemical freeze-out temperature Tch and the chemical potentials for both light and strange quarks (μq, μs) are extracted by comparing the present data with simple model predictions. The μq, μs and Tch from the NA44 are compared with those obtained from similar analysis of SPS S + A and AGS Si + A data. The chemical freeze-out temperature Tch in CERN energy is higher than thermal freeze-out temperature Tfo which is extracted from transverse momentum distribution of charged hadrons. In AGS energy Tch is close to Tfo.

  1. Production of highly charged ion beams from ECR ion sources

    International Nuclear Information System (INIS)

    Electron Cyclotron Resonance (ECR) ion source development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECR ion sources. So far at cw mode operation, up to 300 eμA of O7+ and 1.15 emA of O6+, more than 100 eμA of intermediate heavy ions for charge states up to Ar13+, Ca13+, Fe13+, Co14+ and Kr18+, and tens of eμA of heavy ions with charge states to Kr26+, Xe28+, Au35+, Bi34+ and U34+ have been produced from ECR ion sources. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe36+, Au46+, Bi47+ and U48+. An order of magnitude enhancement for fully stripped argon ions (I ≥ 60 enA) also has been achieved. This article will review the ECR ion source progress and discuss key requirement for ECR ion sources to produce the highly charged ion beams

  2. Charge exchange and X-ray emission in 70 MeV/u Bi-Au collisions

    Energy Technology Data Exchange (ETDEWEB)

    Verma, P. [GSI, D-64291 Darmstadt (Germany) and Vaish College, Rohtak 124 001 (India) and J. Liebig University, D-35392 Giessen (Germany)]. E-mail: P.Verma@gsi.de; Mokler, P.H. [GSI, D-64291 Darmstadt (Germany); JMI University, New Delhi 110 025 (India); Braeuning-Demian, A. [GSI, D-64291 Darmstadt (Germany); Braeuning, H. [JMI University, New Delhi 110 025 (India); Berdermann, E. [GSI, D-64291 Darmstadt (Germany); Chatterjee, S. [GSI, D-64291 Darmstadt (Germany); Gumberidze, A. [GSI, D-64291 Darmstadt (Germany); Hagmann, S. [J.W. Goethe University, D-60486 Frankfurt (Germany); Kozhuharov, C. [GSI, D-64291 Darmstadt (Germany); Orsic-Muthig, A. [GSI, D-64291 Darmstadt (Germany); Reuschl, R. [J.W. Goethe University, D-60486 Frankfurt (Germany); Schoeffler, M. [J.W. Goethe University, D-60486 Frankfurt (Germany); Spillmann, U. [GSI, D-64291 Darmstadt (Germany); Stoehlker, Th. [GSI, D-64291 Darmstadt (Germany); Stachura, Z. [Institute for Nuclear Physics, PL-31-342 Cracow (Poland); Tashenov, S. [GSI, D-64291 Darmstadt (Germany); Wahab, M.A. [Vaish College, Rohtak 124 001 (India)

    2005-07-01

    Charge exchange and X-ray emission for 70 MeV/u highly charged ions of Bi {sup q+} [77 q 82] colliding with thin Au targets [21 t in {mu}g/cm{sup 2} 225] were measured at the heavy ion synchrotron SIS at GSI. For the innermost shells this beam energy implies a quasiadiabatic collision regime. The charge state distribution of the emerging ions was measured by a position sensitive CVD-diamond detector after being analyzed by a magnet spectrometer. Charge exchange cross sections have been deduced from the target thickness dependence of the charge state distribution. Electron capture at distant collision dominates completely over ionization at close collision. The X-ray emission from the collision partners were measured by solid state detectors, Ge(i). The K X-ray emission for closed and open incoming projectile K vacancies gives access to vacancy transfer in the superheavy quasi-molecule transiently formed during collision for the innermost shells.

  3. Ion-atom cold collision: Formation of cold molecular ion by radiative processes

    OpenAIRE

    Rakshit, Arpita; Deb, Bimalendu

    2010-01-01

    We discuss theoretically ion-atom collisions at low energy and predict the possibility of formation of cold molecular ion by photoassociation. We present results on radiative homo- and hetero-nuclear atom-ion cold collisions that reveal threshold behaviour of atom-ion systems.

  4. Progress in numerical calculations of ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Reading, J.F.; Ford, A.L.; Becker, R.L.

    1983-01-01

    An ion-atom collision produces a time dependent perturbation of a many fermion system. In this collision, excitation, ionization and charge transfer can occur. The driving mechanism for these processes may be thought of as the potentials seen by individual electrons at any given separation of the projectile and target nuclei. If we think of these potentials as belonging to the target (a nucleus and electrons) and the projectile (another nucleus and electrons) then as detected by an electron the potentials change because: (a) the target and projectile change position, and (b) electrons on the target and projectile change states. Most work in the past fifty years has concentrated on solving the independent particle model (IPM). Cracks are beginning to appear in this model which only allows for type (a) changes in the potential. But in a short review we shall have quite enough to do in understanding the progress made in the last decade on the IPM. This paper is divided into three parts. The first deals with how to reduce the IPM to the single electron model (SEM). The second is on a new method where charge transfer is important. The third confronts some standard models with modern calculations.

  5. Progress in numerical calculations of ion-atom collisions

    International Nuclear Information System (INIS)

    An ion-atom collision produces a time dependent perturbation of a many fermion system. In this collision, excitation, ionization and charge transfer can occur. The driving mechanism for these processes may be thought of as the potentials seen by individual electrons at any given separation of the projectile and target nuclei. If we think of these potentials as belonging to the target (a nucleus and electrons) and the projectile (another nucleus and electrons) then as detected by an electron the potentials change because: (a) the target and projectile change position, and (b) electrons on the target and projectile change states. Most work in the past fifty years has concentrated on solving the independent particle model (IPM). Cracks are beginning to appear in this model which only allows for type (a) changes in the potential. But in a short review we shall have quite enough to do in understanding the progress made in the last decade on the IPM. This paper is divided into three parts. The first deals with how to reduce the IPM to the single electron model (SEM). The second is on a new method where charge transfer is important. The third confronts some standard models with modern calculations

  6. CERN achievements in relativistic heavy ion collisions

    Directory of Open Access Journals (Sweden)

    Bruno Giuseppe Eugenio

    2015-01-01

    Full Text Available Twenty years after a Letter of Intent by the GSI and LBL groups for the “Study of particle production and target fragmentation in central 20Ne on Pb reactions, at 12 GeV per nucleon energy of the CERN PS external beam" [1], based on the results found by the NA45/CERES, NA49, NA50, and WA97/NA57 experiments at the SPS, CERN announced compelling evidence for the formation of a new state of matter in heavyion collisions at CERN-SPS energies [2]. Some of the experiments were indeed the 2nd or 3rd generation successors of the apparatuses originally proposed by the GSI-LBL collaboration. Actually, the CERN ion program initiated at the SPS with the acceleration of oxygen ions at 60 and 200 GeV/nucleon only in 1986, and continued with sulphur ions at 200 GeV/nucleon up to 1993. The rest is history: lead-ion beams at 160 GeV/nucleon became available at the SPS in 1994; the LHC accelerated and collided lead beams at a center of mass energy per nucleon pair √sNN = 2.76 TeV in 2010. Heavy ion physics is definitely in the future program of CERN: ALICE will operate a major upgrade of its detectors during the second long shutdown of the LHC, in 2018-2019, and the associated physics program will span the third and fourth LHC runs, till late 2020s.

  7. Studies of relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    This report presents the progress in our program of Relativistic Heavy Ion studies. The first phase of experiments on lepton pairs is almost complete and the results from the initial part of this program are presented in copies of three publications. It appears that the origin of lepton pairs is the annihilation of pions. The evidence for this seems to be the shape of the dilepton mass spectrum, the cross-section as a function of energy which seems to scale with pion production, and the general kinematic behavior of the lepton pairs themselves. We present progress on the development of Ring Imaging Cerenkov counters for dilepton observations in general, and a short report on a high resolution method counter proposal that could be adapted to RHIC counters in general. Publication of results on hyperon polarization with incident polarized proton beams is also presented. These results use the phenomenological approach that could be useful in understanding hyperon production in heavy ion collisions. In this connection, a proposal for studying high density nuclear matter with incident antiprotons is presented. Progress on the TPC detectors developed by the BNL group for heavy ion research is reported, along with recent analysis of polarization with incident silicon beams. Finally, the most recent results on subthreshold antiproton production is presented. These latter results are several orders of magnitude more than expected and they point to some kind of coherent hadronic phenomena even at extremely low energies

  8. Charge states of ions, and mechanisms of charge ordering transitions

    International Nuclear Information System (INIS)

    To gain insight into the mechanism of charge ordering transitions, which conventionally are pictured as a disproportionation of an ion M as 2Mn+→M(n+1)+ + M(n−1)+, we (1) review and reconsider the charge state (or oxidation number) picture itself, (2) introduce new results for the putative charge ordering compound AgNiO2 and the dual charge state insulator AgO, and (3) analyze the cationic occupations of the actual (not formal) charge, and work to reconcile the conundrums that arise. We establish that several of the clearest cases of charge ordering transitions involve no disproportion (no charge transfer between the cations, and hence no charge ordering), and that the experimental data used to support charge ordering can be accounted for within density functional-based calculations that contain no charge transfer between cations. We propose that the charge state picture retains meaning and importance, at least in many cases, if one focuses on Wannier functions rather than atomic orbitals. The challenge of modeling charge ordering transitions with model Hamiltonians isdiscussed. (paper)

  9. High Gluon Densities in Heavy Ions Collisions

    CERN Document Server

    Blaizot, Jean-Paul

    2016-01-01

    The early stages of heavy ion collisions are dominated by high density systems of gluons that carry each a small fraction $x$ of the momenta of the colliding nucleons. A distinguishing feature of such systems is the phenomenon of "saturation" which tames the expected growth of the gluon density as the energy of the collision increases. The onset of saturation occurs at a particular transverse momentum scale, the "saturation momentum", that emerges dynamically and that marks the onset of non-linear gluon interactions. At high energy, and for large nuclei, the saturation momentum is large compared to the typical hadronic scale, making high density gluons amenable to a description with weak coupling techniques. This paper reviews some of the challenges faced in the study of such dense systems of small $x$ gluons, and of the progress made in addressing them. The focus is on conceptual issues, and the presentation is both pedagogical, and critical. Examples where high gluon density could play a visible role in hea...

  10. Strangeness production in heavy-ion collisions

    CERN Document Server

    Palmese, Alessia; Drago, Alessandro; Linnyk, Olena; Cassing, Wolfgang

    2015-01-01

    A study of the "horn" in the particle ratio $K^+/\\pi^+$ for central heavy-ion collisions as a function of the collision energy $\\sqrt{s}$ is presented. We analyse two different interpretations: the onset of deconfinement and the transition from a baryon- to a meson-dominated hadron gas. We use a realistic equation of state (EOS), which includes both hadron and quark degrees-of-freedom. The Taub-adiabate procedure is followed to determine the system at the early stage. Our results do not support an explanation of the horn as due to the onset of deconfinement. Using only hadronic EOS we reproduced the energy dependence of the $K^+/\\pi^+$ and $\\Lambda/\\pi^-$ ratios employing an experimental parametrisation of the freeze-out curve. We observe a transition between a baryon- and a meson-dominated regime; however, the reproduction of the $K^+/\\pi^+$ and $\\Lambda/\\pi^-$ ratios as a function of $\\sqrt{s}$ is not completely satisfying. We finally propose a new idea for the interpretation of the data, the roll-over sche...

  11. Atomic physics with highly charged ions

    International Nuclear Information System (INIS)

    This report discusses: One electron outer shell processes in fast ion-atom collisions; role of electron-electron interaction in two-electron processes; multi-electron processes at low energy; multi-electron processes at high energy; inner shell processes; molecular fragmentation studies; theory; and, JRM laboratory operations

  12. Fragmentation of molecular ions in slow electron collisions

    Energy Technology Data Exchange (ETDEWEB)

    Novotny, Steffen

    2008-06-25

    The fragmentation of positively charged hydrogen molecular ions by the capture of slow electrons, the so called dissociative recombination (DR), has been investigated in storage ring experiments at the TSR, Heidelberg, where an unique twin-electron-beam arrangement was combined with high resolution fragment imaging detection. Provided with well directed cold electrons the fragmentation kinematics were measured down to meV collision energies where pronounced rovibrational Feshbach resonances appear in the DR cross section. For thermally excited HD{sup +} the fragmentation angle and the kinetic energy release were studied at variable precisely controlled electron collision energies on a dense energy grid from 10 to 80 meV. The anisotropy described for the first time by Legendre polynomials higher 2{sup nd} order and the extracted rotational state contributions were found to vary on a likewise narrow energy scale as the rotationally averaged DR rate coefficient. Ro-vibrationally resolved DR experiments were performed on H{sub 2}{sup +} produced in distinct internal excitations by a novel ion source. Both the low-energy DR rate as well as the fragmentation dynamics at selected resonances were measured individually in the lowest two vibrational and first three excited rotational states. State-specific DR rates and angular dependences are reported. (orig.)

  13. Fragmentation of molecular ions in slow electron collisions

    International Nuclear Information System (INIS)

    The fragmentation of positively charged hydrogen molecular ions by the capture of slow electrons, the so called dissociative recombination (DR), has been investigated in storage ring experiments at the TSR, Heidelberg, where an unique twin-electron-beam arrangement was combined with high resolution fragment imaging detection. Provided with well directed cold electrons the fragmentation kinematics were measured down to meV collision energies where pronounced rovibrational Feshbach resonances appear in the DR cross section. For thermally excited HD+ the fragmentation angle and the kinetic energy release were studied at variable precisely controlled electron collision energies on a dense energy grid from 10 to 80 meV. The anisotropy described for the first time by Legendre polynomials higher 2nd order and the extracted rotational state contributions were found to vary on a likewise narrow energy scale as the rotationally averaged DR rate coefficient. Ro-vibrationally resolved DR experiments were performed on H2+ produced in distinct internal excitations by a novel ion source. Both the low-energy DR rate as well as the fragmentation dynamics at selected resonances were measured individually in the lowest two vibrational and first three excited rotational states. State-specific DR rates and angular dependences are reported. (orig.)

  14. Hadron Production in Heavy Ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, Hans Georg; Xu, Nu

    2009-05-19

    Heavy ion collisions are an ideal tool to explore the QCD phase diagram. The goal is to study the equation of state (EOS) and to search for possible in-medium modifications of hadrons. By varying the collision energy a variety of regimes with their specific physics interest can be studied. At energies of a few GeV per nucleon, the regime where experiments were performed first at the Berkeley Bevalac and later at the Schwer-Ionen-Synchrotron (SIS) at GSI in Darmstadt, we study the equation of state of dense nuclear matter and try to identify in-medium modifications of hadrons. Towards higher energies, the regime of the Alternating Gradient Synchrotron (AGS) at the Brookhaven National Laboratory (BNL), the Super-Proton Synchrotron (SPS) at CERN, and the Relativistic Heavy Ion Collider (RHIC) at BNL, we expect to produce a new state of matter, the Quark-Gluon Plasma (QGP). The physics goal is to identify the QGP and to study its properties. By varying the energy, different forms of matter are produced. At low energies we study dense nuclear matter, similar to the type of matter neutron stars are made of. As the energy is increased the main constituents of the matter will change. Baryon excitations will become more prevalent (resonance matter). Eventually we produce deconfined partonic matter that is thought to be in the core of neutron stars and that existed in the early universe. At low energies a great variety of collective effects is observed and a rather good understanding of the particle production has been achieved, especially that of the most abundantly produced pions and kaons. Many observations can be interpreted as time-ordered emission of various particle species. It is possible to determine, albeit model dependent, the equation of state of nuclear matter. We also have seen indications, that the kaon mass, especially the mass of the K{sup +}, might be modified by the medium created in heavy ion collisions. At AGS energies and above, emphasis shifts towards

  15. Jet Structure in Heavy Ion Collisions

    CERN Document Server

    Blaizot, Jean-Paul

    2015-01-01

    We review recent theoretical developments in the study of the structure of jets that are produced in ultra relativistic heavy ion collisions. The core of the review focusses on the dynamics of the parton cascade that is induced by the interactions of a fast parton crossing a quark-gluon plasma. We recall the basic mechanisms responsible for medium induced radiation, underline the rapid disappearance of coherence effects, and the ensuing probabilistic nature of the medium induced cascade. We discuss how large radiative corrections modify the classical picture of the gluon cascade, and how these can be absorbed in a renormalization of the jet quenching parameter $\\hat q $. Then, we analyze the (wave)-turbulent transport of energy along the medium induced cascade, and point out the main characteristics of the angular structure of such a cascade. Finally, color decoherence of the in-cone jet structure is discussed. Modest contact with phenomenology is presented towards the end of the review.

  16. Hadronic interferometry in heavy-ion collisions

    International Nuclear Information System (INIS)

    The primary goal of intensity interferometry is to learn about the lifetime of the fireball created in heavy-ion collisions. From this information, it should be possible to further understand the possible formation of quark-gluon plasma. At unrelativistic energies, present interest is focused on two-pion correlations. At intermediate energies, the two-proton interferometry technique is the main topic of review. Recent experiments have been able to yield quantitative information regarding the space-time extensin of nuclear reactions. This review focuses on both the theoretical basis for hadronic interferometry as well as the experimental determination of correlation functions and their calculation via nuclear transport theory. 170 refs., 6 figs

  17. Handbook for highly charged ion spectroscopic research

    CERN Document Server

    Hutton, Roger; Currell, Fred; Martinson, Indrek; Hagmann, Siegbert

    2011-01-01

    Highly charged ions are key research objects in atomic physics. Precision spectroscopy of such ions provides a powerful tool for exploring relativistic and quantum electrodynamics effects. Additionally, the interaction of high-energy heavy-ions with matter is itself a topic of importance in many areas of applied physics, including fusion and plasma physics, accelerator physics, materials science and semiconductor device preparation and behavior. This work provides a complete overview of modern methods of studying highly charged ions. With chapters covering everything from the essential backgro

  18. Electron-ion collision operator in strong electromagnetic fields

    Science.gov (United States)

    Fraiman, Gennadiy; Balakin, Alexey

    2012-10-01

    The pair electron-ion collision operator is found for the kinetic equation describing the one-particle drift distribution in strong electromagnetic fields [1]. The pair collisions are studied under the conditions when the oscillation velocity of an electron driven by an external electromagnetic wave is much larger than the electron drift velocity. The operator is presented in the Boltzmann form and describes collisions with both small and large changes of the particle momentum. In contrast with the Landau collision operator, which describes diffusion in the momentum space, the collision operator that we propose describes a new and very important effect, namely, Coulomb attraction of a wave-driven oscillating electron to an ion due to multiple returns of the electron to the same ion. This effect leads to a large increase of the collision cross-section of electron-ion collisions in strong laser fields, to increased efficiency of the Joule heating in plasma, to the generation of fast electrons through e-i collisions, etc. [4pt] [1] A. A. Balakin and G. M. Fraiman, Electron-ion collision operator in strong electromagnetic fields, EPL 93, 35001 (2011).

  19. Multiply charged ion beams from solid substances

    International Nuclear Information System (INIS)

    The mVINIS Ion Source has enabled us to obtain multiply charged ion beams from gases as well as from solid materials. The solid substance ion beams were produced by using two techniques: a) the evaporation of metals by using the inlet system based on mini-oven and b) the metal-ions-from volatile-compounds method (MIVOC) by using the modified gas inlet system. In the production of high current stable ion beams of solids with relatively high melting points (over 1000 deg) were made great efforts. The B3+ ion beam current of over 300 μA is one of the most intensive beams extracted until now. The obtained multiply charged ion beam spectra of solid substances (B, Fe and Zn) are presented as well as some of the corresponding experimental results achieved during the modification of polymers, carbon materials and fullerenes. (author)

  20. Beam-energy dependence of charge separation along the magnetic field in Au+Au collisions at RHIC

    CERN Document Server

    Adamczyk, L; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Beavis, D R; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Sánchez, M Calderón de la Barca; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, M J M; Contin, G; Cramer, J G; Crawford, H J; Cui, X; Das, S; Leyva, A Davila; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; de Souza, R Derradi; Dhamija, S; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Engle, K S; Eppley, G; Eun, L; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Finch, E; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Girard, M; Gliske, S; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hamed, A; Han, L-X; Haque, R; Harris, J W; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Kosarzewski, L K; Kotchenda, L; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; LeVine, M J; Li, C; Li, W; Li, X; Li, Y; Li, Z M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Don, D M M D Madagodagettige; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Olvitt, D L; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Pile, P; Planinic, M; Pluta, J; Poljak, N; Poniatowska, K; Porter, J; Poskanzer, A M; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; Szelezniak, M A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Vanfossen,, J A; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, X L; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, J; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yan, W; Yang, C; Yang, Y; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zawisza, Y; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J L; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2014-01-01

    Local parity-odd domains are theorized to form inside a Quark-Gluon-Plasma (QGP) which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect (CME). The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this paper, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39 and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy, and tends to vanish by 7.7 GeV. The implications of these results for the CME will be discussed.

  1. Vacuum improvements for ultra high charge state ion acceleration

    International Nuclear Information System (INIS)

    The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10-6 down to about 7 x 10-7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe27+ at 603 MeV, more than doubled for a Bi41+ beam (from 1.9% to 4.6%) at 904 MeV and tripled for a U47+ beam (from 1.2% to 3.6%) at 1,115 MeV. At about 5 NeV/nucleon 92 enA (2.2 pnA) for Bi41+ and 14 enA (0.3 pnA) for U47+ were extracted ut of the 88-Inch Cyclotron Ion beams with charge states as high as U64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models

  2. Behaviour of ion velocity distributions for a simple collision model

    Science.gov (United States)

    St-Maurice, J.-P.; Schunk, R. W.

    1974-01-01

    Calculation of the ion velocity distributions for a weakly ionized plasma subjected to crossed electric and magnetic fields. An exact solution to Boltzmann's equation has been obtained by replacing the Boltzmann collision integral with a simple relaxation model. At altitudes above about 150 km, where the ion collision frequency is much less than the ion cyclotron frequency, the ion distribution takes the shape of a torus in velocity space for electric fields greater than 40 mV/m. This shape persists for one to two hours after application of the electric field. At altitudes where the ion collision and cyclotron frequencies are approximately equal (about 120 km), the ion velocity distribution is shaped like a bean for large electric field strengths. This bean-shaped distribution persists throughout the lifetime of ionospheric electric fields. These highly non-Maxwellian ion velocity distributions may have an appreciable affect on the interpretation of ion temperature measurements.

  3. Hollow ion formation and decay in slow Bi{sup 46+}-C{sub 60} collisions

    Energy Technology Data Exchange (ETDEWEB)

    Thumm, U. [J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)

    1997-01-01

    The interaction of slow highly charged ions with many-electron targets leads to the formation of unstable, multiply excited projectiles. We simulated the formation of such hollow ions for slow incident Bi{sup 46+} projectiles and C{sub 60} targets. Our semiclassical overbarrier simulation includes resonant exchange and Auger emission of electrons. It models the dynamical variation of level occupations and charge states during the collision and predicts highly unstable hollow ions immediately after the collision. With respect to the subsequent downstream relaxation of the hollow ions, we propose a simple relaxation scheme that includes autoionizing and radiative transitions. As a consequence of this downstream relaxation, almost all of the resonantly captured electrons are emitted. {copyright} {ital 1997} {ital The American Physical Society}

  4. Fragment Isospin as a Probe of Heavy-Ion Collisions

    CERN Document Server

    Xu, H; Davin, B; Beaulieu, L; Larochelle, Y; Lefort, T; Yañez, R; De Souza, R T; Liu, T X; Liu, X D; Lynch, W G; Shomin, R; Tan, W P; Tsang, M B; Molen, A V; Wagner, A; Xi Hong Fei; Gelbke, C K; Charity, R J; Sobotka, L G; Botvina, A S

    2002-01-01

    Isotope ratios of fragments produced at mid-rapidity in peripheral and central collisions of 114Cd ions with 92Mo and 98Mo target nuclei at E/A = 50 MeV are compared. Neutron-rich isotopes are preferentially produced in central collisions as compared to peripheral collisions. The influence of the size (A), density, N/Z, E*/A, and Eflow/A of the emitting source on the measured isotope ratios was explored by comparison with a statistical model (SMM). The mid-rapidity region associated with peripheral collisions does not appear to be neutron-enriched relative to central collisions.

  5. Searching for $\\Xi_{cc}^+$ in Relativistic Heavy Ion Collisions

    CERN Document Server

    Zhao, Jiaxin; Zhuang, Pengfei

    2016-01-01

    We study the doubly charmed baryon $\\Xi_{cc}^+$ in high energy nuclear collisions. We solve the three-body Schroedinger equation with relativistic correction and calculate the $\\Xi_{cc}^+$ yield and transverse momentum distribution via coalescence mechanism. For $\\Xi_{cc}^+$ production in central Pb+Pb collisions at LHC energy, the yield is extremely enhanced, and the production cross section per binary collision is one order of magnitude larger than that in p+p collisions. This indicates that, it is most probable to discover $\\Xi_{cc}^+$ in heavy ion collisions and its discovery can be considered as a probe of the quark-luon plasma formation.

  6. Influence of the quantum interference on the bosonic and fermionic ion-ion collisions

    Science.gov (United States)

    Hong, Woo-Pyo; Jung, Young-Dae

    2014-03-01

    The quantum interference effects on the bosonic-bosonic (He-4)-(He-4), fermionic-fermionic (He-3)-(He-3), and bosonic-fermionic (He-4)-(He-3) ion-ion collisions are investigated by using the isotope of the He nucleus in dense semiclassical Coulomb systems with the Faxen-Holtzmark method. It is found that the scattering cross section for the fermionic-fermionic ion-ion collision is greater than the bosonic-bosonic and bosonic-fermionic ion collision cross sections. It is also found that the collisional induced quantum interference effect enhances the ion-ion collision cross section in semiclassical Coulomb systems. The variation of the quantum-mechanical effect on the bosonic and fermionic ion-ion collisions is also discussed. This paper is dedicated to the late Prof. P. K. Shukla in memory of exciting and stimulating collaborations on physical processes in semiclassical Coulomb systems.

  7. Hidden beauty and charm of relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    The goal of the SPS, RHIC, and LHC heavy-ion programs is to validate the existence and study the properties of the quark-gluon plasma (QGP), a phase of strongly - interacting matter at high energy density where quarks and gluons are no longer bound within hadrons. The quarkonia states (J/ψ and γ) have been among the most popular tools since their suppression was proposed as a signal of QGP formation. This is thought to be a direct effect of deconfinement, when the binding potential between the constituents of a quarkonium state, a heavy quark and its antiquark, is screened by the colour charges of the surrounding light quarks and gluons. This feebly bound quarkonia state then can be broken up by the gluon collisions

  8. Fluctuating Glasma initial conditions and flow in heavy ion collisions

    CERN Document Server

    Schenke, Bjoern; Venugopalan, Raju

    2012-01-01

    We compute initial conditions in heavy-ion collisions within the Color Glass Condensate (CGC) framework by combining the impact parameter dependent saturation model (IP-Sat) with the classical Yang-Mills description of initial Glasma fields. In addition to fluctuations of nucleon positions, this IP-Glasma description includes quantum fluctuations of color charges on the length-scale determined by the inverse nuclear saturation scale Q_s. The model naturally produces initial energy fluctuations that are described by a negative binomial distribution. The ratio of triangularity to eccentricity is close to that in a model tuned to reproduce experimental flow data. We compare transverse momentum spectra and v_(2,3,4)(p_T) of pions from different models of initial conditions using relativistic viscous hydrodynamic evolution.

  9. Effect of correlation on cumulants in heavy-ion collisions

    CERN Document Server

    Mishra, D K; Netrakanti, P K

    2015-01-01

    We study the effects of correlation on cumulants and their ratios of net-proton multiplicity distribution which have been measured for central (0-5\\%) Au+Au collisions at Relativistic Heavy Ion Collider (RHIC). This effect has been studied assuming individual proton and anti-proton distributions as Poisson or Negative Binomial Distribution (NBD). In-spite of significantly correlated production due to baryon number, electric charge conservation and kinematical correlations of protons and anti-protons, the measured cumulants of net-proton distribution follow the independent production model. In the present work we demonstrate how the introduction of correlations will affect the cumulants and their ratios for the difference distributions. We have also demonstrated this study using the proton and anti-proton distributions obtained from HIJING event generator.

  10. Fluctuating Glasma Initial Conditions and Flow in Heavy Ion Collisions

    Science.gov (United States)

    Schenke, Björn; Tribedy, Prithwish; Venugopalan, Raju

    2012-06-01

    We compute initial conditions in heavy ion collisions within the color glass condensate framework by combining the impact parameter dependent saturation model with the classical Yang-Mills description of initial Glasma fields. In addition to fluctuations of nucleon positions, this impact parameter dependent Glasma description includes quantum fluctuations of color charges on the length scale determined by the inverse nuclear saturation scale Qs. The model naturally produces initial energy fluctuations that are described by a negative binomial distribution. The ratio of triangularity to eccentricity ɛ3/ɛ2 is close to that in a model tuned to reproduce experimental flow data. We compare transverse momentum spectra and v2,3,4(pT) of pions from different models of initial conditions using relativistic viscous hydrodynamic evolution.

  11. Effect of correlations on cumulants in heavy-ion collisions

    Science.gov (United States)

    Mishra, D. K.; Garg, P.; Netrakanti, P. K.

    2016-02-01

    We study the effects of correlations on cumulants and their ratios of net-proton multiplicity distributions which have been measured for central (0%-5%) Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). This effect has been studied by assuming individual proton and antiproton distributions as a Poisson or negative binomial distribution (NBD). In spite of significantly correlated production due to baryon number, electric charge conservation, and kinematical correlations of protons and antiprotons, the measured cumulants of the net-proton distribution follow the independent-production model. In the present work we demonstrate how the introduction of the correlations will affect the cumulants and their ratios for the difference distributions. We have also demonstrated this study using the proton and antiproton distributions obtained from the hijing event generator.

  12. Atomic physics with highly charged ions: Progress report, 15 August 1985--14 August 1988

    International Nuclear Information System (INIS)

    The study of inelastic collision phenomena with highly charged projectile ions and the interpretation of spectral features resulting from these collisions remain as the major focal points in the atomic physics research at the J.R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas. The title of the research project ''Atomic Physics with Highly Charged Ions'' speaks to these points. The experimental work is made possible locally by the use of relatively high velocity, highly charged projectiles (v typically 5% c) as obtained from the 6 MV tandem Van de Graaff accelerator. The work in the past few years has divided into collisions at high velocity using the primary beams from the accelerator and collisions at low velocity using secondary beams (recoil ions produced in a high velocity collision) in a so-called SIRS (Secondary Ion Recoil Source) geometry. Theoretical calculations have been performed to accurately describe inelastic scattering processes of the one-electron and many-electron type, and to accurately predict atomic transition energies and intensities for x-rays and Auger electrons. Correlation effects and polarization phenomena in ion-atom collisions have been investigated

  13. Spectroscopy with trapped highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  14. Jet results in heavy ion collisions with the ATLAS experiment at the LHC

    CERN Document Server

    Perepelitsa, Dennis; The ATLAS collaboration

    2015-01-01

    In relativistic collisions of heavy ions, a hot medium with a high density of unscreened color charges is produced, and jets propagating through this medium are known to suffer energy loss. This results in several distinct effects seen in central heavy ion collisions: the yield of inclusive jets measured via the nuclear modification factor is observed to be strongly suppressed; the yield of events with highly asymmetric dijet pairs is observed to be increased; the jet fragmentation is modified. In proton-lead collisions, the production of hard processes is expected to be modified via a modification of nuclear parton distribution functions. While the theory predicts rather small effects to be observed, the data show interesting unexpected features: the nuclear modification factor exhibits a strong centrality dependence; charged particle spectra show an enhancement at large transverse momenta with respect to the proton-proton reference. In this talk, we will summarize the most recent results by ATLAS involving ...

  15. Identified charged hadron production in pp and Pb-Pb collisions with ALICE at the LHC

    CERN Document Server

    Vasileiou, Maria

    2015-01-01

    Nuclear matter under extreme conditions can be investigated in ultra-relativistic heavy-ion collisions. The measurement of transverse momentum distributions and yields of identified particles is a fundamental step in understanding collective and thermal properties of the matter produced in such collisions. The ALICE Experiment results on identified charged hadron production are presented for pp collisions at \\sqrt{s} = 0.9, 2.76 and 7 TeV and for Pb-Pb collisions at \\sqrt{s_{NN}} = 2.76 TeV. Spectral shapes, production yields and nuclear modification factors are shown and compared to previous experiments and Monte Carlo predictions. The spectral shapes in Pb-Pb collisions indicate a strong increase of the radial flow velocity with respect to RHIC energies, which in hydrodynamic models is expected as a consequence of the increasing particle density. The observed suppression of high transverse momentum particles in central Pb-Pb collisions provides evidence for strong parton energy loss in the hot and dense med...

  16. Beta decay of highly charged ions

    International Nuclear Information System (INIS)

    Ion storage rings and ion traps provide the very first opportunity to address nuclear beta decay under conditions prevailing in hot stellar plasmas during nucleosynthesis, i.e. at high atomic charge states. Experiments are summarized that were performed in this field during the last decade at the ion storage-cooler ring ESR in Darmstadt. Special emphasis is given to the first observation of bound-state beta decay, where the created electron remains bound in an inner orbital of the daughter atom. The impact of this specific 'stellar' decay mode for s-process nucleosynthesis as well as for nuclear 'eon clocks' is outlined. Finally, a new technique, single-ion decay spectroscopy, is presented, where one observes two-body beta decay characteristics (i.e. orbital electron capture or bound-state beta decay) of highly charged, single ions for well-defined nuclear and atomic quantum states of both the mother - and the daughter - ion.

  17. Charged-Particle Multiplicity in Proton-Proton Collisions

    OpenAIRE

    Grosse-Oetringhaus, Jan Fiete; Reygers, Klaus

    2009-01-01

    This article summarizes and critically reviews measurements of charged-particle multiplicity distributions and pseudorapidity densities in p+p(pbar) collisions between sqrt(s) = 23.6 GeV and sqrt(s) = 1.8 TeV. Related theoretical concepts are briefly introduced. Moments of multiplicity distributions are presented as a function of sqrt(s). Feynman scaling, KNO scaling, as well as the description of multiplicity distributions with a single negative binomial distribution and with combinations of...

  18. Heavy Ion Collisions at the LHC - Last Call for Predictions

    International Nuclear Information System (INIS)

    In August 2006, the CERN Theory Unit announced to restructure its visitor program and to create a 'CERN Theory Institute', where 1-3 month long specific programs can take place. The first such Institute was held from 14 May to 10 June 2007, focusing on 'Heavy Ion Collisions at the LHC - Last Call for Predictions'. It brought together close to 100 scientists working on the theory of ultra-relativistic heavy ion collisions. The aim of this workshop was to review and document the status of expectations and predictions for the heavy ion program at the Large Hadron Collider LHC before its start. LHC will explore heavy ion collisions at ∼ 30 times higher center of mass energy than explored previously at the Relativistic Heavy Ion Collider RHIC. So, on the one hand, the charge of this workshop provided a natural forum for the exchange of the most recent ideas, and allowed to monitor how the understanding of heavy ion collisions has evolved in recent years with the data from RHIC, and with the preparation of the LHC experimental program. On the other hand, the workshop aimed at a documentation which helps to distinguish pre- from post-dictions. An analogous documentation of the 'Last Call for Predictions' (1) was prepared prior to the start of the heavy-ion program at the Relativistic Heavy Ion Collider RHIC, and it proved useful in the subsequent discussion and interpretation of RHIC data. The present write-up is the documentation of predictions for the LHC heavy ion program, received or presented during the CERN TH Institute. The set-up of the CERN TH Institute allowed us to aim for the wide-most coverage of predictions. There were more than 100 presentations and discussions during the workshop. Moreover, those unable to attend could still participate by submitting predictions in written form during the workshop. This followed the spirit that everybody interested in making a prediction had the right to be heard. To arrive at a concise document, we required that each

  19. Heavy Ion Collisions at the LHC - Last Call for Predictions

    Energy Technology Data Exchange (ETDEWEB)

    Armesto, N; Borghini, N; Jeon, S; Wiedemann, U A; Abreu, S; Akkelin, V; Alam, J; Albacete, J L; Andronic, A; Antonuv, D; Arleo, F; Armesto, N; Arsene, I C; Barnafoldi, G G; Barrette, J; Bauchle, B; Becattini, F; Betz, B; Bleicher, M; Bluhm, M; Boer, D; Bopp, F W; Braun-Munzinger, P; Bravina, L; Busza, W; Cacciari, M; Capella, A; Casalderrey-Solana, J; Chatterjee, R; Chen, L; Cleymans, J; Cole, B A; delValle, Z C; Csernai, L P; Cunqueiro, L; Dainese, A; de Deus, J D; Ding, H; Djordjevic, M; Drescher, H; Dremin, I M; Dumitru, A; El, A; Engel, R; d' Enterria, D; Eskola, K J; Fai, G; Ferreiro, E G; Fries, R J; Frodermann, E; Fujii, H; Gale, C; Gelis, F; Goncalves, V P; Greco, V; Gyulassy, M; van Hees, H; Heinz, U; Honkanen, H; Horowitz, W A; Iancu, E; Ingelman, G; Jalilian-Marian, J; Jeon, S; Kaidalov, A B; Kampfer, B; Kang, Z; Karpenko, I A; Kestin, G; Kharzeev, D; Ko, C M; Koch, B; Kopeliovich, B; Kozlov, M; Kraus, I; Kuznetsova, I; Lee, S H; Lednicky, R; Letessier, J; Levin, E; Li, B; Lin, Z; Liu, H; Liu, W; Loizides, C; Lokhtin, I P; Machado, M T; Malinina, L V; Managadze, A M; Mangano, M L; Mannarelli, M; Manuel, C; Martinez, G; Milhano, J G; Mocsy, A; Molnar, D; Nardi, M; Nayak, J K; Niemi, H; Oeschler, H; Ollitrault, J; Paic, G; Pajares, C; Pantuev, V S; Papp, G; Peressounko, D; Petreczky, P; Petrushanko, S V; Piccinini, F; Pierog, T; Pirner, H J; Porteboeuf, S; Potashnikova, I; Qin, G Y; Qiu, J; Rafelski, J; Rajagopal, K; Ranft, J; Rapp, R; Rasanen, S S; Rathsman, J; Rau, P; Redlich, K; Renk, T; Rezaeian, A H; Rischke, D; Roesler, S; Ruppert, J; Ruuskanen, P V; Salgado, C A; Sapeta, S; Sarcevic, I; Sarkar, S; Sarycheva, L I; Schmidt, I; Shoski, A I; Sinha, B; Sinyukov, Y M; Snigirev, A M; Srivastava, D K; Stachel, J; Stasto, A; Stocker, H; Teplov, C Y; Thews, R L; Torrieri, G; Pop, V T; Triantafyllopoulos, D N; Tuchin, K L; Turbide, S; Tywoniuk, K; Utermann, A; Venugopalan, R; Vitev, I; Vogt, R; Wang, E; Wang, X N; Werner, K; Wessels, E; Wheaton, S; Wicks, S; Wiedemann, U A; Wolschin, G; Xiao, B; Xu, Z; Yasui, S; Zabrodin, E; Zapp, K; Zhang, B

    2008-02-25

    In August 2006, the CERN Theory Unit announced to restructure its visitor program and to create a 'CERN Theory Institute', where 1-3 month long specific programs can take place. The first such Institute was held from 14 May to 10 June 2007, focusing on 'Heavy Ion Collisions at the LHC - Last Call for Predictions'. It brought together close to 100 scientists working on the theory of ultra-relativistic heavy ion collisions. The aim of this workshop was to review and document the status of expectations and predictions for the heavy ion program at the Large Hadron Collider LHC before its start. LHC will explore heavy ion collisions at {approx} 30 times higher center of mass energy than explored previously at the Relativistic Heavy Ion Collider RHIC. So, on the one hand, the charge of this workshop provided a natural forum for the exchange of the most recent ideas, and allowed to monitor how the understanding of heavy ion collisions has evolved in recent years with the data from RHIC, and with the preparation of the LHC experimental program. On the other hand, the workshop aimed at a documentation which helps to distinguish pre- from post-dictions. An analogous documentation of the 'Last Call for Predictions' [1] was prepared prior to the start of the heavy-ion program at the Relativistic Heavy Ion Collider RHIC, and it proved useful in the subsequent discussion and interpretation of RHIC data. The present write-up is the documentation of predictions for the LHC heavy ion program, received or presented during the CERN TH Institute. The set-up of the CERN TH Institute allowed us to aim for the wide-most coverage of predictions. There were more than 100 presentations and discussions during the workshop. Moreover, those unable to attend could still participate by submitting predictions in written form during the workshop. This followed the spirit that everybody interested in making a prediction had the right to be heard. To arrive at a concise

  20. Newly appreciated roles for electrons in ion-atom collisions

    International Nuclear Information System (INIS)

    Since the previous Debrecen workshop on High-Energy Ion-Atom Collisions there have been numerous experiments and substantial theoretical developments in the fields of fast ion-atom and ion- solid collisions concerned with explicating the previously largely underappreciated role of electrons as ionizing and exciting agents in such collisions. Examples to be discussed include the double electron ionization problem in He; transfer ionization by protons in He; double excitation in He; backward scattering of electrons in He; the role of electron-electron interaction in determining beta parameters for ELC; projectile K ionization by target electrons; electron spin exchange in transfer excitation; electron impact ionization in crystal channels; resonant coherent excitation in crystal channels; excitation and dielectronic recombination in crystal channels; resonant transfer and excitation; the similarity of recoil ion spectra observed in coincidence with electron capture vs. electron loss; and new research on ion-atom collisions at relativistic energies

  1. Electromagnetic effects on meson production: a new tool for studying the space-time evolution of heavy ion collisions

    OpenAIRE

    Rybicki, Andrzej; Szczurek, Antoni; Klusek-Gawenda, Mariola; Davis, Nikolaos; Ozvenchuk, Vitalii; Kielbowicz, Miroslaw

    2016-01-01

    We review our studies of spectator-induced electromagnetic (EM) effects on the emission of charged mesons in the final state of ultrarelativistic heavy ion collisions. We argue that these effects offer sensitivity to the distance $d_E$ between the charged meson formation zone at freeze-out and the spectator system. As such, the can serve as an independent, new tool to probe the space time evolution and longitudinal of the system created in the collision. As a phenomenological application for ...

  2. Influence of charge changing collisions on charge state distributions (CSD) in non-equilibrium plasmas

    International Nuclear Information System (INIS)

    For an optimal design of ion sources and for some aspects of plasma diagnostics it is important to study the influence of all processes and parameters that are essential for the production and loss of multiply charged ions. Till now all existing calculations of CSD neglected charge transfer because of missing data. Now many of the very big charge transfer cross sections are measured and so we are able to include them into our calculations. (orig.)

  3. Hadronic Resonances in Heavy-Ion Collisions at ALICE

    Directory of Open Access Journals (Sweden)

    Knospea A. G.

    2012-11-01

    Full Text Available Modifications to the masses and widths of hadronic resonances in heavy-ion collisions could be a sign of chiral symmetry restoration. Uncorrected spectra, masses, and widths of the ϕ(1020 and K*(8920 resonances have been measured in Pb–Pb collisions at √sNN = 2.76 TeV using the ALICE detector. These measurements are presented and compared to resonances in other collision systems.

  4. Rotating quark-gluon plasma in relativistic heavy ion collisions

    CERN Document Server

    Jiang, Yin; Liao, Jinfeng

    2016-01-01

    We study the rotational collective motion of the quark-gluon plasma in relativistic heavy ion collisions using the widely-adopted AMPT (A Multi-Phase Transport) model. The global angular momentum, the average vorticity carried by the quark-gluon plasma, and the locally defined vorticity fields are computed for Au+Au collisions, with detailed information of their time evolution, spatial distribution, as well as the dependence on beam energy and collision centrality.

  5. Hadronic Resonances in Heavy-Ion Collisions at ALICE

    CERN Document Server

    Knospe, A G

    2012-01-01

    Modifications to the masses and widths of hadronic resonances in heavy-ion collisions could be a sign of chiral symmetry restoration. Uncorrected spectra, masses, and widths of the phi(1020) and K*(892)0 resonances have been measured in Pb-Pb collisions at 2.76 TeV using the ALICE detector. These measurements are presented and compared to resonances in other collision systems.

  6. Energetic ion-atom collisions: early beginnings and recent advances

    International Nuclear Information System (INIS)

    From the discovery of canal rays and radioactivity to the invention of accelerators and the first applications of the Born approximation, some developments which were seminal for the development of ion-atom collisions are described. Collision theory is shown to have played a key role in the evolution of the early quantum theory and of quantum mechanics and its probability interpretation

  7. $\\eta$ Production in Peripheral Heavy-Ion Collisions

    OpenAIRE

    Schramm, Alec J.; Reeves, Daniel H.

    1995-01-01

    We estimate the impact parameter dependence of the production cross section for $\\eta_c$ and $\\eta_b$ mesons in peripheral heavy-ion collisions collisions. Total and elastic $\\gamma\\gamma$ cross sections are calculated in an equivalent photon approximation.

  8. Physics Opportunities in Ultraperipheral Heavy Ion Collisions at LHC

    OpenAIRE

    Baur, G.

    2001-01-01

    Due to coherence, there are strong electromagnetic fields of short duration in very peripheral heavy ion collisions. They give rise to photon-photon and photon-nucleus collisions with high flux. Photon-photon and photon-hadron physics at various invariant mass scales are discussed.

  9. Equilibrium charge state distributions of 14N and 20Ne ions emerging from solids

    International Nuclear Information System (INIS)

    A new technique of backscattering has been developed for the measurement of equilibrium charge state distributions of ions emerging from a solid medium. By this method, equilibrium charge fractions for nitrogen in the energy range from 0.8 to 1.7 MeV and for neon from 1.5 to 4.4 MeV have been measured. The influence of inner shell vacancies produced by violent collisions on the charge state equilibrium is discussed. (Auth.)

  10. Ion distribution function in ion space-charge region

    International Nuclear Information System (INIS)

    Experimental results for the ion distribution functions measured into an ion space-charge region near the negatively biased grid of a multipolar confinement plasma system are presented. The ion space charge is produced in argon plasma at a pressure of about 10-4 mbar. Plasma parameters in source chamber were electron density in the range 108 to 1010 cm-3 and electron temperature in the range 0.5 to 6.0 eV. The ion distribution functions were measured using a small electrostatic analyser with two grids of about 8 mm effective diameter and 48% optical transparency. The are two regimes for ion space-charge formation: one regime is stable and another is unstable. The latter consists of large current fluctuations in external electrical circuits. The ion distribution functions for both regimes are measured and the differences between them are pointed out. In the nonstationary regime the ion distribution functions are broader than in the stationary one. This effect is more important if the distance between the grid and the electrostatic analyser is greater than the ion space-charge position. (authors)

  11. Integral cross section measurements and product recoil velocity distributions of Xe2+ + N2 hyperthermal charge-transfer collisions

    Science.gov (United States)

    Hause, Michael L.; Prince, Benjamin D.; Bemish, Raymond J.

    2016-07-01

    Charge exchange from doubly charged rare gas cations to simple diatomics proceeds with a large cross section and results in populations of many vibrational and electronic product states. The charge exchange between Xe2+ and N2, in particular, is known to create N2 + in both the A and B electronic states. In this work, we present integral charge exchange cross section measurements of the Xe2+ + N2 reaction as well as axial recoil velocity distributions of the Xe+ and N2 + product ions for collision energies between 0.3 and 100 eV in the center-of-mass (COM) frame. Total charge-exchange cross sections decrease from 70 Å2 to about 40 Å2 with increasing collision energy through this range. Analysis of the axial velocity distributions indicates that a Xe2+ - N2 complex exists at low collision energies but is absent by 17.6 eV COM. Analysis of the axial velocity distributions reveals evidence for complexes with lifetimes comparable to the rotational period at low collision energies. The velocity distributions are consistent with quasi-resonant single charge transfer at high collision energies.

  12. Integral cross section measurements and product recoil velocity distributions of Xe(2+) + N2 hyperthermal charge-transfer collisions.

    Science.gov (United States)

    Hause, Michael L; Prince, Benjamin D; Bemish, Raymond J

    2016-07-28

    Charge exchange from doubly charged rare gas cations to simple diatomics proceeds with a large cross section and results in populations of many vibrational and electronic product states. The charge exchange between Xe(2+) and N2, in particular, is known to create N2 (+) in both the A and B electronic states. In this work, we present integral charge exchange cross section measurements of the Xe(2+) + N2 reaction as well as axial recoil velocity distributions of the Xe(+) and N2 (+) product ions for collision energies between 0.3 and 100 eV in the center-of-mass (COM) frame. Total charge-exchange cross sections decrease from 70 Å(2) to about 40 Å(2) with increasing collision energy through this range. Analysis of the axial velocity distributions indicates that a Xe(2+) - N2 complex exists at low collision energies but is absent by 17.6 eV COM. Analysis of the axial velocity distributions reveals evidence for complexes with lifetimes comparable to the rotational period at low collision energies. The velocity distributions are consistent with quasi-resonant single charge transfer at high collision energies. PMID:27475363

  13. Elliptic and triangular flow in asymmetric heavy-ion collisions

    International Nuclear Information System (INIS)

    We present a study of the elliptic (v2) and triangular (v3) flow and their corresponding eccentricity fluctuations for asymmetric (Au+Ag, Au+Cu, and Au+Si) collisions at √(sNN) = 200 GeV. These are compared to the corresponding results from symmetric (Au+Au and Cu+Cu) collisions at the same energy. The study which is carried out using a multiphase transport (AMPT) model shows that triangularity (ε3), fluctuations in triangularity and v3 do not show much variation for the different colliding ion sizes studied. However the eccentricity (ε2), fluctuations in eccentricity and v2, shows a strong dependence on colliding ion size for a given number of participating nucleons. Our study thus indicates that asymmetric heavy-ion collisions could be used to constrain models dealing with flow fluctuations in heavy-ion collisions.

  14. Particle Production in High-energy Heavy-ion Collisions

    OpenAIRE

    Wang, Xin-Nian

    2001-01-01

    Particle production mechanisms in high-energy heavy-ion collisions are reviewed in connection with recent experimental data from RHIC. Implications on mini-jet production, parton saturation and jet quenching are discussed.

  15. Status of chemical equilibrium in relativistic heavy-ion collisions

    Indian Academy of Sciences (India)

    J Cleymans

    2003-04-01

    Recent work on chemical equilibrium in heavy-ion collisions is reviewed. The energy dependence of thermal parameters is discussed. The centrality dependence of thermal parameters at SPS energies is presented.

  16. Elliptic and Triangular flow in asymmetric heavy-ion collisions

    CERN Document Server

    Haque, Md Rihan; Mohanty, Bedangadas

    2011-01-01

    We present a study of the elliptic (v2) and triangular (v3) flow and their corresponding eccentricity fluctuations for asymmetric (Au+Ag, Au+Cu and Au+Si) collisions at \\sqrt_NN = 200 GeV. These are compared to the corresponding results from symmetric (Au+Au and Cu+Cu) collisions at the same energy. The study which is carried out using a multi-phase transport (AMPT) model shows that triangularity (\\epsilon_3), fluctuations in triangularity and v3 do not show much variation for the different colliding ion sizes studied. However the eccentricity (\\epsilon_2), fluctuations in eccentricity and v2 shows a strong dependence on colliding ion size for a given number of participating nucleons. Our study thus indicates that asymmetric heavy-ion collisions could be used to constrain models dealing with flow fluctuations in heavy-ion collisions.

  17. Highly charged ions trapping for lifetime measurements

    International Nuclear Information System (INIS)

    A new experimental setup dedicated to highly charged ion trapping is presented in this work. The final goal is to perform lifetime measurement of metastable states produced by our ECR (Electron Cyclotron Resonance) ion source. Lifetimes to be measured are in the range of a few ms and more. We have measured the lifetimes of the M1 transitions of the metastable states of Ar9+, Ar13+ and Ar14+. These measurements are useful to test the N-body problem in the relativistic range. The trap we have built, was designed a few years ago at the Weizman Institute in Israel, it allows ions with an energy of several keV to be trapped for lifetimes of about 1 second. This trap was originally designed to study the dynamics of excited molecules. We have shown for the first time how the trap operates and that it can operate with highly charged ions. We have studied the beam dynamics of highly charged ions and the trap has been tested with various species of ions and different charge states: from O+ to O6+, from Ar8+ to Ar13+, and from Kr13+ to Kr20+

  18. Experimental recombination rates for highly charged ions

    International Nuclear Information System (INIS)

    Recent studies of recombination between free electrons and highly charged ions using electron coolers of heavy-ion storage rings have produced accurate rate coefficients of interest for plasma modeling and diagnostics. Some surprises were discovered which can lead to revisions of recombination models. With bare ions one finds at low energy a strong and puzzling deviation from radiative recombination theory. Dielectronic recombination with C3+, N4+) show that jj coupling gives essential contributions to the cross section also for light ions. (author)

  19. High energy heavy ion collisions from the view point of the 'strong field physics'

    International Nuclear Information System (INIS)

    In the high energy heavy ion collisions at the facilities like RHIC and LHC, two strongest fields in the present universe are generated. First of all, a very strong electromagnetic field is generated, though its duration is very short due to the very high speed collisions of nuclei and the large electric charges. On the other hand, the nuclei are described as the high density saturation gluon state just before the moment of the collision and the high density gluon is released by the collision. A very strong color electromagnetic field is generated. The color glass condensate (CGC) is a reasonable picture. In this text, dynamics of the GLASMA (Glass + plasma), the new physics brought about by those 'strong fields', are introduced and are explained how the yet unsolved problems of the heavy ion collisions are going to be investigated on the new view point. The mechanism of the apparitions of the strong electromagnetic field and the strong color electromagnetic field are explained at first. The heavy ion collisions can be described as the process CGC to develop into QGP. As the phenomena under the strong electromagnetic field and the heavy ion collisions, their synchrotron radiations, the photon birefringence, the photon decay, the splitting of photons and the chiral phase transitions under high field are picked up. Concerning the strong color electromagnetic field dynamics and the heavy ion collisions, the plasma flux tube dynamics, the color magnetic flux tube, the color electric flux tube and the coexisting case of the color electric field and magnetic field are presented. (S. Funahashi)

  20. Phenomenology of Heavy Flavors in Ultrarelativistic Heavy-Ion Collisions

    CERN Document Server

    Isayev, A A

    2010-01-01

    Some recent experimental results obtained in collisions of heavy nuclei ($\\sqrt{s}=200$ GeV) at BNL Relativistic Heavy-Ion Collider (RHIC) are discussed. The probes of dense matter created in heavy-ion collision by quarkonia, $D$ and $B$ mesons containing heavy charm and beauty quarks are considered. The centrality, rapidity and transverse momentum dependences of the nuclear modification factor and elliptic flow coefficient are presented and their possible theoretical interpretation is provided.

  1. Mach cones in viscous heavy-ion collisions

    OpenAIRE

    Bouras, I.; Betz, B.; Z. Xu; Greiner, C.(Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main, Germany)

    2014-01-01

    The formation of Mach cones is studied in a full $(3+1)$-dimensional setup of ultrarelativistic heavy-ion collisions, considering a transverse and longitudinal expanding medium at Relativistic Heavy-Ion Collider energies. For smooth initial conditions and central collisions the jet-medium interaction is investigated using high-energy jets and various values of the ratio of shear viscosity over entropy density, $\\eta/s$. For small viscosities, the formation of Mach cones is proven, whereas for...

  2. Molecular Dynamics Simulation of Myoglobin Collision with Low Energy Ions

    Institute of Scientific and Technical Information of China (English)

    CHENG Wei; ZHANG Feng-Shou; ZHOU Hong-Yu

    2007-01-01

    Collisions of a low energy heavy ion with a myoglobin in water are simulated by molecular dynamics model. The increase of total energy is very small. The mean squared fluctuation decreases at 300 K and increases at 250K.This is an important novel cooling effect that protects the protein from ion damage. The possible collision side effect is the change of tertiary structure that blocks the normal functions of the myogiobin.

  3. Lambda-Lambda Correlation in Relativistic Heavy Ion Collisions

    OpenAIRE

    Morita Kenji; Furumoto Takenori; Ohnishi Akira

    2015-01-01

    We investigate Λ − Λ correlation function in relativistic heavy ion collisions to extract their interaction. Using an expanding source model for heavy ion collisions, we disentangle effects of collective expansion and those of the interaction at low relative momenta. Then, we discuss the influence of the feed-down correction for Σ0 decay and indicate the possible existence of a residual correlation at high relative momenta. Consequently, the present STAR data suggest a weakly attractive inter...

  4. On the multiplicity fluctuations in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    In the present letter we discuss the general features of the multiplicity distributions in relativistic heavy ion collisions. It is shown that from simple statistical considerations it is possible to predict the dependence of the dispersions of multiplicity distributions on the average multiplicities in any given rapidity window. The applicability of the negative binomial distribution to multiplicity distributions from collisions with heavy ions is discussed. (orig.)

  5. Production and ion-ion cooling of highly charged ions in electron string ion source.

    Science.gov (United States)

    Donets, D E; Donets, E D; Donets, E E; Salnikov, V V; Shutov, V B; Syresin, E M

    2009-06-01

    The scheme of an internal injection of Au atoms into the working space of the "Krion-2" electron string ion source (ESIS) was applied and tested. In this scheme Au atoms are evaporated from the thin tungsten wire surface in vicinity of the source electron string. Ion beams with charge states up to Au51+ were produced. Ion-ion cooling with use of C and O coolant ions was studied. It allowed increasing of the Au51+ ion yield by a factor of 2. Ions of Kr up to charge state 28+ were also produced in the source. Electron strings were first formed with injection electron energy up to 6 keV. Methods to increase the ESIS ion output are discussed. PMID:19566200

  6. Medical radiation dosimetry theory of charged particle collision energy loss

    CERN Document Server

    McParland, Brian J

    2014-01-01

    Accurate radiation dosimetry is a requirement of radiation oncology, diagnostic radiology and nuclear medicine. It is necessary so as to satisfy the needs of patient safety, therapeutic and diagnostic optimisation, and retrospective epidemiological studies of the biological effects resulting from low absorbed doses of ionising radiation. The radiation absorbed dose received by the patient is the ultimate consequence of the transfer of kinetic energy through collisions between energetic charged particles and atoms of the tissue being traversed. Thus, the ability of the medical physicist to both measure and calculate accurately patient dosimetry demands a deep understanding of the physics of charged particle interactions with matter. Interestingly, the physics of charged particle energy loss has an almost exclusively theoretical basis, thus necessitating an advanced theoretical understanding of the subject in order to apply it appropriately to the clinical regime. ​ Each year, about one-third of the worl...

  7. Azimuthal angular correlations between heavy-flavour decay particles and charged hadrons in pp collisions in ALICE

    International Nuclear Information System (INIS)

    Heavy quarks produced in pp and heavy ion collisions are studied using heavy-flavour decay electrons and heavy-flavour mesons. Detailed understanding of the production processes and fragmentation of heavy quarks can be obtained by studying the azimuthal angular correlation of heavy-flavour hadrons. The azimuthal angular correlations of heavy-flavour mesons and charged hadrons can be used to disentangle charm and beauty-hadrons in pp collisions. In this contribution the fraction of electrons from beauty-hadron decays in the heavy-flavour decay electron yield is shown as well as the beauty production cross section in pp collisions at √S = 2.76 TeV. The measurements are compared to the predictions from next-to leading order perturbative QCD calculations. We also show the results from correlation analysis of charged D* mesons and hadrons performed using pp collision data at √S = 7 TeV

  8. Transverse energy distribution, charged particle multiplicities and spectra in 16O-nucleus collisions

    International Nuclear Information System (INIS)

    The HELIOS (High Energy Lepton and Ion Spectrometer) experiment, installed at the CERN Super Proton Synchrotron, proposes to examine in details the physical properties of a state of high energy created in nuclei by ultra-relativistic nucleus-nucleus collisions. It is generally believed that, at high densities or temperatures, a phase transition to a plasma of quark and gluons will occur. The dynamic of the expansion of such a plasma and its subsequent condensation into a hadron gas should markedly affect the composition and momentum distribution of the emerging particles and photons. The HELIOS experimental setup therefore combines 4π calorimetric coverage with measurements of inclusive particle spectra, two particle correlations, low and high mass lepton pairs and photons. The emphasis is placed on transverse energy flow (E/sub T/) measurements with good energy resolution, and the ability to trigger the acquisition of data in a variety of E/sub T/ ranges, thereby selecting the impact parameter or the violence of the collisions. This short note presents HELIOS results, for the most part still preliminary, on 16O-nucleus collisions at the incident energies of 60 and 200 GeV per nucleon. The E/sub T/ distributions from Al, Ag and W targets are discussed and compared to the associated charged particle multiplicities from W. Charged particle and (converted) photon spectra measured with the external magnetic spectrometer are compared for 16O + W and p + W collisions at 200 GeV per nucleon. 5 refs., 7 figs

  9. Jets and Vector Bosons in Heavy Ion Collisions

    CERN Document Server

    De La Cruz, Begona

    2013-01-01

    This paper reviews experimental results on jets and electroweak boson (photon, W and Z) production in heavy-ion collisions, from the CMS and ATLAS detectors, using data collected during 2011 PbPb run and pp data collected at an equivalent energy. By comparing the two collision systems, the energy loss of the partons propagating through the medium produced in PbPb collisions can be studied. Its characterization is done using dijet events and isolated photon-jet pairs. Since the electroweak gauge bosons do not participate in the strong interaction, and are thus unmodified by the nuclear medium, they serve as clean probes of the initial state in the collision.

  10. Jets and Vector Bosons in Heavy Ion Collisions

    Science.gov (United States)

    de la Cruz, Begoña

    2013-11-01

    This paper reviews experimental results on jets and electroweak boson (photon,Wand Z) production in heavy-ion collisions, from the CMS and ATLAS detectors, using data collected during 2011 PbPb run and pp data collected at an equivalent energy. By comparing the two collision systems, the energy loss of the partons propagating through the medium produced in PbPb collisions can be studied. Its characterization is done using dijet events and isolated photon-jet pairs. Since the electroweak gauge bosons do not participate in the strong interaction, and are thus unmodified by the nuclear medium, they serve as clean probes of the initial state in the collision.

  11. Scaling relations in elastic scattering cross sections between multiply charged ions and hydrogen

    International Nuclear Information System (INIS)

    Differential elastic scattering cross sections of bare ions from hydrogen are calculated using the eikonal approximation. The results satisfy a scaling relation involving the scattering angle, the ion charge and a factor related to the ion mass. A semiclassical explanation in terms of a distant collision hypothesis for small scattering angle is proposed. A unified picture of related scaling rules found in direct processes is discussed. (author)

  12. Negative ions produced in multicharged ions and C{sub 60} collisions

    Energy Technology Data Exchange (ETDEWEB)

    Martin, S; Bredy, R; Montagne, G; Bernard, J; Chen, L [Universite de Lyon, F-69622, Lyon (France); Universite Lyon 1, Villeurbanne (France); CNRS, UMR5579, LASIM (France); Salmoun, A [Laboratory of Instrumentation Measure and Control, Physics Department, Faculty of Sciences, University Chouaib Doukkali, BP 20 El Jadida (Morocco); Ma, X, E-mail: smartin@univ-lyon1.fr [Institute of Modern Physic, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2011-06-15

    We have measured the differential cross-sections in F{sup 3+}-C{sub 60} collisions at low velocity (v=0.18 a.u.). Using coincidence measurements between the ejected electron number and recoil ions, we have estimated the initial charge state of C{sub 60} parent ions associated with neutral outgoing projectiles to range from 4+ to 7+. We found that the formation of anions is correlated with the strong excitation of C{sub 60} (average excitation energy about 160 eV). The cross-section of the production of the anion has been found to be 25 a.u. This value is in agreement with the scenario of anion formation in two steps. In the first step, F{sup 3+} ions are neutralized by multicollision on the C{sub 60} surface. In the second step and at the exit part of the collision, the electron attachment process occurs. For the production of a stable anion, the capture of electrons on carbon must occur directly to the ground states of F{sup -}, giving many electron vacancies on C{sub 60}. This process explains the observation of strong electronic and vibronic excitations of C{sub 60} leading to electron emission and multifragmentation processes.

  13. Transverse momentum and transverse mass distributions of charged hadrons produced in Au-Au collisions at high energies

    Institute of Scientific and Technical Information of China (English)

    Liu Fu-Hu

    2008-01-01

    The transverse momentum distribution and the transverse mass distribution of charged hadrons produced in nucleus-nucleus collisions at high energies are described by using a two-cylinder model. The results calculated by the model are compared and found to be in agreement with the experimental data of the STAR and E895 Collaborations, measured in Au-Au collisions at the relativistic heavy ion collider (RHIC) and alternating-gradient synchrotron (AGS) energies, respectively. In the energy range concerned, the excitation degree of emission source close to the central axis of cylinders increases obviously with the collision centrality and incident energy increasing, but it does not show any obvious change with the increase of the (pseudo) rapidity in central collisions. The excitation degree of emission source close to the side-surface of cylinders does not show any obvious change with the collision centrality, the (pseudo) rapidity, and the incident energy increasing.

  14. Perturbed stationary state approach to nuclear heavy ion collision

    International Nuclear Information System (INIS)

    In order to treat the nuclear heavy ion collision at low energy, the perturbed stationary state method developed in the atomic collision is extended so as to include the coupling between the internal state and the angular part of the relative motion. It is shown that this method provides a simple interpretation for the molecular resonances observed in the scatterings of 12C + 12C, 12C + 16O and 16O + 16O, and for the induced rotation mechanism during the collision between heavy ions. Also given is the detailed study for the applicability of the perturbation treatment of this method. (author)

  15. Holographic description of QGP production in heavy ion collisions

    Science.gov (United States)

    Aref'eva, Irina

    2016-01-01

    Dual holographic approach provides a powerful tool to study the static properties of the QGP as well as its thermalization. There are holographic models that reproduce perfectly the static properties of the QGP, meanwhile others holographic models are used to get non-static characteristics such as the thermalization time in heavy ions collisions and the charged multiplicity. Holographic thermalization means a black hole formation in the dual space-time and particles multiplicities is defined by the entropy of the produced black hole. In this talk, we report results (arXiv:1409.7558) of study the holographic thermalization in a bottom-up AdS/QCD dual confinement background that provides the Cornell potential and QCD β -function. We perturb this background by colliding domain shock waves that are assumed to be dual to colliding heavy ions. It is known, that only for a special background the entropy of the black hole produced in the domain shock waves collision reproduces energy dependence of particles multiplicities obtained at RHIC and LHC. This background is different from the confinement background. We note that this special background approximates the confinement background in an intermediate domain. We assume that the main part of entropy is produced in this intermediate domain. This permits us to estimate the thermalization time. We show that the dependence of the multiplicity on the energy for the intermediate background has an asymptotic expansion whose first term depends on energy as E1/3, which is rather close to the experimental dependence of particles multiplicities on colliding ions energy obtained at RHIC and LHC. Motivated by recent experimental indications in favor of anisotropic thermalization, we also discuss a holographic thermalization scenario in the anisotropic 5-dimensional Lifshitz-like background. Collision of domain walls in this background has been recently considered in (arXiv:1410.4595). Our estimates show that for the critical exponent

  16. Charge state and energy loss of relativistic heavy ions in matter

    International Nuclear Information System (INIS)

    Relativistic heavy-ion collisions of few-electron projectiles ranging from argon up to uranium have been investigated in solid and gaseous media. Electron-loss and electron-capture cross sections, charge-state distributions, as well as energy loss and energy deposition have been measured and are compared with theoretical predictions. Especially fully-ionized heavy projectiles represent a unique possibility to test atomic-collision theories. (orig.)

  17. Effects of Electron-Transfer Coupled with Collision-Induced Dissociation (ET/CID) on Doubly Charged Peptides and Phosphopeptides

    Science.gov (United States)

    Liu, Chih-Wei; Lai, Chien-Chen

    2011-01-01

    Electron-transfer dissociation (ETD) is a useful peptide fragmentation technique that can be applied to investigate post-translational modifications (PTMs), the sequencing of highly hydrophilic peptides, and the identification of large peptides and even intact proteins. In contrast to traditional fragmentation methods, such as collision-induced dissociation (CID), ETD produces c- and z·-type product ions by randomly cleaving the N-Cα bonds. The disappointing fragmentation efficiency of ETD for doubly charged peptides and phosphopeptide ions has been improved by ETcaD (supplemental activation). However, the ETD data derived from most database search algorithms yield low confidence scores due to the presence of unreacted precursors and charge-reduced ions within MS/MS spectra. In this work, we demonstrate that eight out of ten standard doubly charged peptides and phosphopeptides can be effortlessly identified by electron-transfer coupled with collision-induced dissociation (ET/CID) using the SEQUEST algorithm without further spectral processing. ET/CID was performed with the further dissociation of the charge-reduced ions isolated from ETD ion/ion reactions. ET/CID had high fragmentation efficiency, which elevated the confidence scores of doubly charged peptide and phosphospeptide sequencing. ET/CID was found to be an effective fragmentation strategy in "bottom-up" proteomic analysis.

  18. Nanodots formation with slow highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Yasunori [Graduate School of Arts and Sciences, University of Tokyo and RIKEN (Japan)

    2007-06-15

    We have been developing a compact electron beam ion source with a high-T{sub c}superconductor as a solenoid magnet, which can be operated at liquid nitrogen temperature, and can deliver slow highly-charged ions as high as q 42. With this ion source together with other ion sources, nanodot formation processes were studied for a highly oriented pyrolytic graphite (HOPG) plate as a target. The impact site was observed with both the scanning tunnelling microscope (STM) mode and non-contact atomic force microscope (NCAFM) mode. It was found that protrusion-like dots were observed for both modes at the same position, and one HCI induced one dot. The dot size (diameter) and height were observed to be more or less the same for both modes, i.e, an HCI impact induces topographic modification on the HOPG surface. The dot size and height were measured as functions of the charge state (q = 8-46) and the kinetic energy (E = 1-300 keV) of highly-charged ions. It was found that the dot size increased linearly with the charge state, although the dependence on the kinetic energy was very weak if any.

  19. An integrated Boltzmann+hydrodynamics approach to heavy ion collisions

    International Nuclear Information System (INIS)

    In this thesis the first fully integrated Boltzmann+hydrodynamics approach to relativistic heavy ion reactions has been developed. After a short introduction that motivates the study of heavy ion reactions as the tool to get insights about the QCD phase diagram, the most important theoretical approaches to describe the system are reviewed. The hadron-string transport approach that this work is based on is the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) approach. Predictions for the charged particle multiplicities at LHC energies are made. The next step is the development of a new framework to calculate the baryon number density in a transport approach. Time evolutions of the net baryon number and the quark density have been calculated at AGS, SPS and RHIC energies. Studies of phase diagram trajectories using hydrodynamics are performed. The hybrid approach that has been developed as the main part of this thesis is based on the UrQMD transport approach with an intermediate hydrodynamical evolution for the hot and dense stage of the collision. The full (3+1) dimensional ideal relativistic one fluid dynamics evolution is solved using the SHASTA algorithm. Three different equations of state have been used, namely a hadron gas equation of state without a QGP phase transition, a chiral EoS and a bag model EoS including a strong first order phase transition. For the freeze-out transition from hydrodynamics to the cascade calculation two different set-ups are employed. The parameter dependences of the model are investigated and the time evolution of different quantities is explored. The hybrid model calculation is able to reproduce the experimentally measured integrated as well as transverse momentum dependent v2 values for charged particles. The multiplicity and mean transverse mass excitation function is calculated for pions, protons and kaons in the energy range from Elab=2-160 A GeV. The HBT correlation of the negatively charged pion source created in central

  20. An integrated Boltzmann+hydrodynamics approach to heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Hannah

    2009-04-22

    In this thesis the first fully integrated Boltzmann+hydrodynamics approach to relativistic heavy ion reactions has been developed. After a short introduction that motivates the study of heavy ion reactions as the tool to get insights about the QCD phase diagram, the most important theoretical approaches to describe the system are reviewed. The hadron-string transport approach that this work is based on is the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) approach. Predictions for the charged particle multiplicities at LHC energies are made. The next step is the development of a new framework to calculate the baryon number density in a transport approach. Time evolutions of the net baryon number and the quark density have been calculated at AGS, SPS and RHIC energies. Studies of phase diagram trajectories using hydrodynamics are performed. The hybrid approach that has been developed as the main part of this thesis is based on the UrQMD transport approach with an intermediate hydrodynamical evolution for the hot and dense stage of the collision. The full (3+1) dimensional ideal relativistic one fluid dynamics evolution is solved using the SHASTA algorithm. Three different equations of state have been used, namely a hadron gas equation of state without a QGP phase transition, a chiral EoS and a bag model EoS including a strong first order phase transition. For the freeze-out transition from hydrodynamics to the cascade calculation two different set-ups are employed. The parameter dependences of the model are investigated and the time evolution of different quantities is explored. The hybrid model calculation is able to reproduce the experimentally measured integrated as well as transverse momentum dependent v{sub 2} values for charged particles. The multiplicity and mean transverse mass excitation function is calculated for pions, protons and kaons in the energy range from E{sub lab}=2-160 A GeV. The HBT correlation of the negatively charged pion source

  1. Ion specific effects on charged interfaces

    OpenAIRE

    Medda, Luca

    2013-01-01

    The physico-chemical phenomena occurring at charged interfaces are specifically affected by the type and the concentration of electrolytes. This has implications both in living and in inorganic systems. The discovery of the ‘ion specific effects’ dates back to Hofmeister (1888), who observed the specific effect of salts in promoting egg white proteins precipitation. Nowadays we are aware that ion specific effects are ubiquitous in all fields of science and technology where electrolytes play a...

  2. Electromagnetic processes in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    A study of the processes generated by the electromagnetic interaction in relativistic nuclear, and atomic collisions is presented. Very strong electromagnetic fields for a very short time are present in distant collisions with no nuclear contact. Such fields can also lead to interesting effects, which are discussed here. (orig.)

  3. The study of hadron dynamics in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    In this thesis, pion emission patterns were studied in two reaction systems Ar + Ca and Au + Au at 1 GeV/u, with the aim to improve the understanding of the pion production in relativistic heavy ion collisions. The study of the high energy tail of the π0-momentum spectrum was regarded as promising because of its sensitivity to compression since it did not appear in small reaction systems. Experiments were performed with TAPS together with the Forward Wall of the FoPi-collaboration at GSI. The combined measurement of charged particle multiplicities in the Forward Wall and the particles entering TAPS enabled an exclusive study of the pion production. TAPS was tested in separate experiments and its capabilities were demonstrated by measuring different reaction products, like photons, charged particles and neutrons. The data analysis involved new methods to treat the background contamination below the invariant mass peak of the π0-meson due to the geometry of the detector and to perform particle identification in a high particle multiplicity environment. (orig.)

  4. Probing the hardest branching of jets in heavy ion collisions

    CERN Document Server

    Chien, Yang-Ting

    2016-01-01

    We present the first calculation of the momentum sharing and angular separation distributions between the leading subjets inside a reconstructed jet in heavy ion collisions. These observables are directly sensitive to the hardest branching in the process of jet formation and are, therefore, ideal for studying the early stage of the in-medium parton shower evolution. The modification of the momentum sharing and angular separation distributions in lead-lead relative to proton-proton collisions is evaluated using the leading-order medium-induced splitting functions obtained in the framework of soft-collinear effective theory with Glauber gluon interactions. Qualitative and in most cases quantitative agreement between theory and preliminary CMS measurements suggests that the parton shower in heavy ion collisions can be dramatically modified early in the branching history. We propose a new measurement which will illuminate the angular distribution of the hardest branching within jets in heavy ion collisions.

  5. Skyrme tensor force in heavy ion collisions

    Science.gov (United States)

    Stevenson, P. D.; Suckling, E. B.; Fracasso, S.; Barton, M. C.; Umar, A. S.

    2016-05-01

    Background: It is generally acknowledged that the time-dependent Hartree-Fock (TDHF) method provides a useful foundation for a fully microscopic many-body theory of low-energy heavy ion reactions. The TDHF method is also known in nuclear physics in the small-amplitude domain, where it provides a useful description of collective states, and is based on the mean-field formalism, which has been a relatively successful approximation to the nuclear many-body problem. Currently, the TDHF theory is being widely used in the study of fusion excitation functions, fission, and deep-inelastic scattering of heavy mass systems, while providing a natural foundation for many other studies. Purpose: With the advancement of computational power it is now possible to undertake TDHF calculations without any symmetry assumptions and incorporate the major strides made by the nuclear structure community in improving the energy density functionals used in these calculations. In particular, time-odd and tensor terms in these functionals are naturally present during the dynamical evolution, while being absent or minimally important for most static calculations. The parameters of these terms are determined by the requirement of Galilean invariance or local gauge invariance but their significance for the reaction dynamics have not been fully studied. This work addresses this question with emphasis on the tensor force. Method: The full version of the Skyrme force, including terms arising only from the Skyrme tensor force, is applied to the study of collisions within a completely symmetry-unrestricted TDHF implementation. Results: We examine the effect on upper fusion thresholds with and without the tensor force terms and find an effect on the fusion threshold energy of the order several MeV. Details of the distribution of the energy within terms in the energy density functional are also discussed. Conclusions: Terms in the energy density functional linked to the tensor force can play a non

  6. Charge transfer cross sections for Hg+, Xe+, and Cs+ in collision with various metals and carbon

    International Nuclear Information System (INIS)

    Cross sections for charge transfer between Hg+, Xe+, and Cs+ and the atomic species Fe, Mo, Al, Ti, Ta, and C have been measured in the ion energy range from 1 to 5000 eV. In general, the cross sections for charge transfer were found to be less than 2 x 10-15 cm2 for most processes over the total energy range. The one exception is Hg+ in collision with Ti. The reactants are all open shell atomic species and in most cases where the charge transfer process is exothermic, several resonant pathways exist leading to the products. Some discussion of possible reaction paths is given. The techniques used to form neutral beams of the various species studied is included

  7. Charge transfer cross sections for Hg + , Xe + , and Cs + in collision with various metals and carbon

    Science.gov (United States)

    Rutherford, J. A.; Vroom, D. A.

    1981-01-01

    Cross sections for charge transfer between Hg+, Xe+, and Cs+ and the atomic species Fe, Mo, Al, Ti, Ta, and C have been measured in the ion energy range from 1 to 5000 eV. In general, the cross sections for charge transfer were found to be less than 2×10-15 cm2 for most processes over the total energy range. The one exception is Hg+ in collision with Ti. The reactants are all open shell atomic species and in most cases where the charge transfer process is exothermic, several resonant pathways exist leading to the products. Some discussion of possible reaction paths is given. The techniques used to form neutral beams of the various species studied is included.

  8. X-Ray Emission Cross Sections following Charge Exchange by Multiply-Charged Ions of Astrophysical Interest

    Energy Technology Data Exchange (ETDEWEB)

    Otranto, S; Olson, R E; Beiersdorfer, P

    2007-03-12

    The CTMC method is used to calculate emission cross sections following charge exchange processes involving highly charged ions of astrophysical interest and typical cometary targets. Comparison is made to experimental data obtained on the EBIT-I machine at Lawrence Livermore National Laboratory LLNL for O{sup 8+} projectiles impinging on different targets at a collision energy of 10 eV/amu. The theoretical cross sections are used together with ion abundances measured by the Advanced Composition Explorer to reproduce cometary spectra. Discrepancies due to different estimated delays of solar wind events between the comet and the Earth-orbiting satellite are discussed.

  9. Track reconstruction in heavy ion collisions with the CMS silicon tracker

    CERN Document Server

    Roland, C

    2006-01-01

    The Large Hadron Collider at CERN will collide protons at \\sqrtS = 14TeV and lead ions at \\sqrt$\\S_{NN}$. The study of heavy ion collisions is an integral part of the physics program of the Compact Muon Solenoid (CMS). Central heavy ion events at LHC energies are expected to produce a multiplicity of up to 3500 charged particles per unit of rapidity. The CMS detector features a large acceptance and high resolution silicon tracker consisting of pixel and strip detector layers. We describe the algorithms used for pattern recognition in the very high track density environment of heavy ion collisions. Detailed studies using the full detector simulation and reconstruction are presented and achieved reconstruction efficiencies, fake rates and resolutions are discussed.

  10. Charge transfer and structured vibrational distributions in H++CH4 low-energy collisions

    International Nuclear Information System (INIS)

    Inelastic and charge transfer collisions of protons with methane molecules have been investigated in a perpendicular-plane crossed beam experiment via the detection of the scattered protons and H atoms, respectively. Time-of-flight analysis of the protons and H atoms at scattering angles 00≤θ≤100 and collision energies 10≤E≤30 eV provided information on internal energy distributions of the CH4 and CH+4 products. Excitation of the n(ν1 ,ν3) +m (ν2 ,ν4) type vibrations, with n,m = 0, 1, 2,xxxwas found to be the most probable assignment of the observed structured energy distributions of CH4 (1 A1 ) at θ≤40. At θ>40, the energy transfer increases steeply up to the dissociation limit while the vibrational structure was no longer resolved. In the case of charge transfer, the observed narrow internal energy distributions corresponding to a most probable average internal energy of CH+4 of about 0.95 eV was centered at the recombination energy of the proton indicative of quasiresonant charge transfer. In addition, fragmentation of CH+4 formed in charge transfer collisions of H+ with CH4 was investigated in an independent experiment using mass spectrometric analysis to identify the individual fragment species. The relative intensities of the parent and fragment ions (i.e., of CH+4, CH+3, and CH+2) were found to be in good agreement with the known values of the appearance potentials of the fragment ions and the distribution of the CH+4 internal energy as obtained from the differential cross sections

  11. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions (updated 1993)

    International Nuclear Information System (INIS)

    Following our previous compilations [IPPJ-AM-45 (1986), NIFS-DATA-7 (1990)], bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1980-1992 are included. For easy finding references for particular combination of collision partners, a simple list is also provided. (author) 1542 refs

  12. Evolution of the nuclide distribution and heat partition along the dissipation path in heavy ion collisions

    International Nuclear Information System (INIS)

    We discuss several problems of nuclear physics with heavy ions. Special attention is paid to close collisions, where impact parameters are considerably smaller than the corresponding grazing values. Such collisions can lead to a formation of a compound nucleus (fusion) or to two body exit channels with a sizable loss of kinetic energy and large transfer of mass and charge between interacting nuclei (damped collisions). A short survey of experimental works done with my participation and devoted to fusion reactions is presented. This is followed by presentation of new experimental results in the field of damped collisions. The data demonstrate that the N/Z equilibration and temperature equilibration are not rapid processes. A distinct correlation between the net nucleon transfer and the heating of the acceptor nucleus is observed. Experimental data are compared with the transport model. Disagreement between model and experiment is discussed. 113 refs. (author)

  13. Photodetachment of the negatively charged hydrogen ions

    CERN Document Server

    Frolov, Alexei M

    2015-01-01

    Photodetachment cross-sections of the negatively charged hydrogen ion(s) ${}^{\\infty}$H$^{-}$, ${}^{1}$H$^{-}$ (protium), ${}^{2}$H$^{-}$ (deuterium D$^{-}$) and ${}^{3}$H$^{-}$ (tritium T$^{-}$) are determined with the use of highly accurate, truly correlated, variational wave functions constructed for these ions. Our approach is based on some efficient and numerically stable formulas for the three-particle integrals with the Bessel functions of the first kind which have been derived recently. Application of the Rayleigh's formula for the spherical Bessel functions drastically simplifies the whole procedure and makes it numerically stable.

  14. Analysis of Ion Charge States in Solar Wind and CMEs

    Indian Academy of Sciences (India)

    Arati Dasgupta; J. M. Laming

    2008-03-01

    We discuss needs in dielectronic recombination data motivated by recent work directed at a quantitative understanding of ion charge states of various elements observed in situ in the solar wind and CMEs. The competing processes of ionization and recombination lead to departures from collision ionization equilibrium. The use of this as a diagnostic of acceleration and heating processes of the solar wind and CMEs is sensitive to the accuracy of the atomic rates in a way that steady state ionization equilibrium plasmas are not. The most pressing need is dielectronic recombination rates for ions Fe8+-12+. These are among the dominant species observed in various regions of the solar wind and CMEs, and in remotely sensed EUV spectra.

  15. The High-Energy Limit of Electromagnetic Pair Production in Heavy-Ions Collisions

    International Nuclear Information System (INIS)

    In recent experiments at the SPS, and in the near future colliding-beam accelerators, such as RHIC and LHC, peripheral heavy-ions collisions produce strong, Lorentz contracted electromagnetic fields. The high charges and high energies of the ions give large cross sections for electromagnetic lepton - antilepton pair production. In this work, a non-perturbative treatment of pair production under these extreme conditions is considered. The two-center Dirac equation for an electron in the external electromagnetic field of two colliding heavy ions in the limit in which the ions are moving at the speed of light is exactly solved off the light fronts using light-front variables and a light-fronts representation. The electromagnetic fields of the ions are confined to the light fronts by the extreme Lorentz contraction and by a choice of gauge designed to incorporate the long-range Coulomb effects into the definition of the asymptotic states. After the peripheral collision, as the ions move apart, the solution in the space between them is determined by the non-trivial boundary conditions at the light fronts. An exact integral representation for the free pair creation amplitudes off the light fronts is obtained by calculating the transition currents flowing from the light fronts into the space between the separating ions. The condition for the applicability of this nonperturbative solution for large but finite collision energy is found, and used to explain recent experimental results according to which the measured production rates scale as the square of the projectile and target charges, even for large charges. It is shown that this observed scaling of positron yields is a result of an exact cancellation of a nonperturbative charge dependence. Nonperturbative effects may contribute significantly to the small-momentum-transfer regime, and to asymptotic states on the light fronts, as well as to results for multiple pair-production, and for correlations between the produced

  16. Freeze-Out Parameters in Heavy-Ion Collisions at AGS, SPS, RHIC, and LHC Energies

    International Nuclear Information System (INIS)

    We review the chemical and kinetic freeze-out conditions in high energy heavy-ion collisions for AGS, SPS, RHIC, and LHC energies. Chemical freeze-out parameters are obtained using produced particle yields in central collisions while the corresponding kinetic freeze-out parameters are obtained using transverse momentum distributions of produced particles. For chemical freeze-out, different freeze-out scenarios are discussed such as single and double/flavor dependent freeze-out surfaces. Kinetic freeze-out parameters are obtained by doing hydrodynamic inspired blast wave fit to the transverse momentum distributions. The beam energy and centrality dependence of transverse energy per charged particle multiplicity are studied to address the constant energy per particle freeze-out criteria in heavy-ion collisions

  17. Proceedings of the Budapest workshop on relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    This volume is the Proceedings of the Budapest workshop on relativistic heavy ion collisions held in Budapest, 10-13 Aug, 1992. The topics include experimental heavy ion physics, Bose-Einstein correlations, intermittency, relativistic transport theory, Quark-Gluon Plasma rehadronization, astronuclear physics and cosmology. All contributions were indexed and abstracted. (author)

  18. The theory of relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    This program began in January 1993. Its primary goals are studies of highly excited matter and its production in nuclear collisions at very high energies. After a general orientation on the project, abstracts describing the contents of completed papers and providing some details of current projects are given. Principal topics of interest are the following: the dynamics of nuclear collisions at very high energies (RHIC and LHC), the dynamics of nuclear collisions at AGS energies, high-temperature QCD and the physics of the quark-gluon plasma, and the production of strangelets and other rare objects

  19. Monte Carlo simulations of the influence of ion-neutral collisions on the ion currents collected by electrostatic probes

    Energy Technology Data Exchange (ETDEWEB)

    Trunec, D. [Masaryk Univ., Brno (Czech Republic). Dept. of Physical Electronics; Spanel, P. [Academy of Sciences of the Czech Republic, Prague (Czech Republic). J. Heyrovsky Inst. of Physical Chemistry; Smith, D. [Keele Univ., Hartshill, Stoke-on-Trent (United Kingdom). Centre for Science and Technology in Medicine

    2002-07-01

    We have carried out Monte Carlo simulation of the motion of Ar{sup +} ions in the space charge sheath surrounding a cylindrical Langmuir probe. The ion currents to the probe have been calculated from these simulations and the percentages of ions crossing the sheath boundary that are collected by the probe have been determined. It has been shown that the collisions of ions with neutral helium gas atoms in the sheath increase the percentage of ions collected by the probe above that predicted by collisionless orbital motion limited current (OMLC) theory at lower helium pressure and decrease this percentage below the OMLC theory prediction at higher helium pressure. It has been shown also that the ion current almost does not depend on probe radius at higher helium pressures. The results of the simulations have been compared with recent Langmuir probe measurements made in flowing afterglow plasmas and with other probe theories. (orig.)

  20. Hydrogen negative ions and collisions of atomic particles

    International Nuclear Information System (INIS)

    This paper will be an overview presenting some of the basic atomic collisions processes (gas phase) which are fundamental to production and destruction of H-(D-). More detailed discussions of the most important processes will be left to other papers at this Symposium, and primarily new results since the 1977 Symposium will be discussed. Recent results provide insight into mechanisms responsible for the high H-(D-) ion fractions in hydrogen gas discharges, and the ion-atom collision processes important for double capture negative ion sources are better understood than in 1977

  1. Azimuthally-integrated HBT parameters for charged pions in nuclear-nuclear collisions versus initial energy

    CERN Document Server

    Okorokov, V A

    2014-01-01

    In the paper energy dependence of space-time extent of charged pion source is studied for various ion collisions for all experimentally available energies. There are no sharp changing of femtoscopy parameter values with increasing of $\\sqrt{s_{NN}}$ in domain of collision energies $\\sqrt{s_{NN}} \\geq 5$ GeV. Energy dependence of estimations for emission duration is almost flat for all energy domain under study within large error bars. Analytic function is suggested for smooth approximation of energy dependence of main HBT parameters. Fit curves demonstrate reasonable agreement with experimental data for most femtoscopy parameters in energy domain $\\sqrt{s_{NN}} \\geq 5$ GeV. Estimations of femtoscopy observables are obtained for energies of the LHC and FCC project.

  2. Mid-rapidity charged hadron transverse spherocity in pp collisions simulated with Pythia

    International Nuclear Information System (INIS)

    The pp collisions have been studied for a long time, however, there are still some effects which are not completely understood, such as the long range angular correlations and the flow patterns in high multiplicity events, which were recently discovered at the LHC. In a recent work it was demonstrated that in Pythia 8, multi-parton interactions and color reconnection can give some of the observed effects similar to the collective flow well known from heavy-ion collisions. Now using the same model, a study based on mid-rapidity charged hadron transverse spherocity is presented. The main purpose of this work is to show that a differential study combining multiplicity and event shapes opens the possibility to understand better the features of data, specially at high multiplicity

  3. Mid-rapidity charged hadron transverse spherocity in pp collisions simulated with Pythia

    Science.gov (United States)

    Ortiz, Antonio; Cuautle, Eleazar; Paić, Guy

    2015-09-01

    The pp collisions have been studied for a long time, however, there are still some effects which are not completely understood, such as the long range angular correlations and the flow patterns in high multiplicity events, which were recently discovered at the LHC. In a recent work it was demonstrated that in Pythia 8, multi-parton interactions and color reconnection can give some of the observed effects similar to the collective flow well known from heavy-ion collisions. Now using the same model, a study based on mid-rapidity charged hadron transverse spherocity is presented. The main purpose of this work is to show that a differential study combining multiplicity and event shapes opens the possibility to understand better the features of data, specially at high multiplicity.

  4. Determination of Energy-Transfer Distributions in Ionizing Ion-Molecule Collisions

    Science.gov (United States)

    Maclot, S.; Delaunay, R.; Piekarski, D. G.; Domaracka, A.; Huber, B. A.; Adoui, L.; Martín, F.; Alcamí, M.; Avaldi, L.; Bolognesi, P.; Díaz-Tendero, S.; Rousseau, P.

    2016-08-01

    The ionization and fragmentation of the nucleoside thymidine in the gas phase has been investigated by combining ion collision with state-selected photoionization experiments and quantum chemistry calculations. The comparison between the mass spectra measured in both types of experiments allows us to accurately determine the distribution of the energy deposited in the ionized molecule as a result of the collision. The relation of two experimental techniques and theory shows a strong correlation between the excited states of the ionized molecule with the computed dissociation pathways, as well as with charge localization or delocalization.

  5. Electron-Positron Production in Ultra-Peripheral Heavy-Ion Collisions with the STAR Experiment

    OpenAIRE

    Morozov, Vladimir Borisovitch

    2004-01-01

    This thesis presents a measurement of the cross-section of the purely electromagnetic production of $e^+e^-$ pairs accompanied by mutual nuclear Coulomb excitation $AuAu\\to Au^*Au^*+e^+e^-$, in ultra-peripheral gold-gold collisions at RHIC at the center-of-mass collision energy of $\\sqrt{s_{NN}} = 200$ GeV per nucleon. These reactions were selected by detecting neutron emission by the excited gold ions in the Zero Degree Calorimeters. The charged tracks in the $e^+e^-$ events were reconstruct...

  6. Some soft aspects of relativistic ion collisions

    CERN Document Server

    Boimska, Bozena

    2009-01-01

    Concepts of wounded nucleon and quark participants have been used for years to parametrize and/or to explain many features of high energy nuclear collisions. Some results illustrating successes and failures of these two approaches are presented, including the latest developments. In particular, results on identified particle production from nuclear collisions measured by the NA49 experiment at the CERN-SPS are shown. The study has been done for both the nucleon and the constituent quark frameworks using the nuclear overlap model. In addition, some preliminary observations concerning the behavior of pT spectra at forward rapidities, expressed in terms of the nuclear modification factor, for hadron-nucleus collisions at the SPS energy are also presented. These results are in relevance to RHIC results for deuteron-gold collisions often interpreted as a manifestation of saturation and/or color glass condensate.

  7. Studies of highly charged ions with EBIT and Super-EBIT

    International Nuclear Information System (INIS)

    The LLNL electron beam ion traps provide cold highly charged ions up to bare U. These machines have provided a wealth of atomic physics data using a compact, relatively inexpensive, device. The physics program has studied electron-ion collisions, QED, ion-surface interactions, and plasmas physics among many other topics. The prospects for the study of the highest charge states in the highest Z ions led to the beam energy upgrade of the first EBIT into Super-EBIT. The desire to use ions as a research probe in themselves led to an ion extraction program on EBIT-2. Finally, a Penning trap (referred to as the RETRAP) has been constructed to catch extracted ions where they can be further cooled and studied. Results of several experiments at the LLNL EBIT facility are described. The program's capabilities are discussed

  8. Learning from numerical calculations of ion-atom collisions

    International Nuclear Information System (INIS)

    Violent collision of two independent many-particle systems, victims, are discussed in the atomic sphere. The asymmetric region where the charge of the projectile Z/sub p/ is less than the target nuclear charge Z/sub n/ is now well understood though interesting details still need to be worked out. Negatively charged projectiles offer a new illustration of Fadeev re-arrangement collisions. Multi-electron coherence effects illustrate the richness of the field but a symmetric (Z/sub p/ approx. Z/sub n/) collision treatment is needed. A new one and a half center expansion method promises a solution to this problem. Future areas of interest are discussed

  9. Detection method for dissociation of multiple-charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Richard D. (Richland, WA); Udseth, Harold R. (Richland, WA); Rockwood, Alan L. (Richland, WA)

    1991-01-01

    Dissociations of multiple-charged ions are detected and analyzed by charge-separation tandem mass spectrometry. Analyte molecules are ionized to form multiple-charged parent ions. A particular charge parent ion state is selected in a first-stage mass spectrometer and its mass-to-charge ratio (M/Z) is detected to determine its mass and charge. The selected parent ions are then dissociated, each into a plurality of fragments including a set of daughter ions each having a mass of at least one molecular weight and a charge of at least one. Sets of daughter ions resulting from the dissociation of one parent ion (sibling ions) vary in number but typically include two to four ions, one or more multiply-charged. A second stage mass spectrometer detects mass-to-charge ratio (m/z) of the daughter ions and a temporal or temporo-spatial relationship among them. This relationship is used to correlate the daughter ions to determine which (m/z) ratios belong to a set of sibling ions. Values of mass and charge of each of the sibling ions are determined simultaneously from their respective (m/z) ratios such that the sibling ion charges are integers and sum to the parent ion charge.

  10. Multiplicity and Pseudorapidity distributions of charged particles in asymmetric and deformed nuclear collisions in a Wounded Quark Model

    CERN Document Server

    Chaturvedi, O S K; Kumar, Ashwini; Singh, B K

    2016-01-01

    The charged particle multiplicity ($n_{ch}$) and pseudorapidity density $(dn_{ch}/d\\eta)$ are key observables to characterize the properties of matter created in heavy ion collisions. The dependence of these observables on collision energy and the collision geometry are a key tool to understand the underlying particle production mechanism. Recently a lot of focus on asymmetric nuclei as well as deformed nuclei collisions has been made as these collisions can provide a deeper understanding of the nature of quantum chromodynamics (QCD). On phenomenological perspective a unified model which describes the experimental data coming from various kind of collision experiments, is much needed to provide the physical insights about the production mechanism. In this paper, firstly we have calculated the charged hadron multiplicities for nucleon-nucleus (such as proton-lead (p-Pb) and asymmetric nuclei collisions like deutron-gold (d-Au), and copper-gold (Cu-Au) within our recently proposed wounded quark model (WQM) and ...

  11. Cluster ions and multiply charged ions formed in frozen CO2 molecules under heavy ion impact

    International Nuclear Information System (INIS)

    A variety of cluster ions, positive or negative, as well as multiply charged atomic ions have been observed from the frozen CO2 targets under (MeV/amu) energetic, highly charged projectile ion impact. Their spectra are found to be quite different from those produced in the cooled expanding CO2 gas targets

  12. Experimental study of the fragmentation of water clusters induced by multiply charged ions

    International Nuclear Information System (INIS)

    This work deals with the fragmentation of neutral water clusters induced by collisions with slow and swift multiply charged ions. Strong projectile charge dependence is found for all of the fragmentation patterns in the charge transfer regime. When increasing the projectile charge (from q = 2 to q = 20), we observe a modification of the scenario of the fragmentation dynamics with a transition from a partial dissociation to a full cluster explosion. We observe that water clusters are more strongly heated by Xe20+ than by He2+. These results are in contrast to the generally accepted idea that highly charged ions are an efficient tool to ionize the target at large impact parameters without a huge amount of energy transfer. The results obtained with high energy projectiles Ni25+ i.e. in the ionization regime, are very similar than those obtained with low velocity Xe20+ i.e. in the charge transfer regime. These results suggest that even if the primary mechanism is different, the 'same' electrons are into play and ejected from the target. In this work, we have also produced size-selected protonated water clusters by the coupling of an Electro-Spray Ion source together with a quadrupole mass filter. In order to perform, in the next future, collisions between these size-selected water clusters and projectile ions, we designed and realized a new experimental device which allows us to produce intense singly charged ions beams. (author)

  13. Pseudorapidity correlations in heavy ion collisions from viscous fluid dynamics

    Science.gov (United States)

    Monnai, Akihiko; Schenke, Björn

    2016-01-01

    We demonstrate by explicit calculations in 3+1 dimensional viscous relativistic fluid dynamics how two-particle pseudorapidity correlation functions in heavy ion collisions at the LHC and RHIC depend on the number of particle producing sources and the transport properties of the produced medium. In particular, we present results for the Legendre coefficients of the two-particle pseudorapidity correlation function, an,m, in Pb+Pb collisions at 2760 GeV and Au+Au collisions at 200 GeV from viscous hydrodynamics with three dimensionally fluctuating initial conditions. Our results suggest that the an,m provide important constraints on initial state fluctuations in heavy ion collisions.

  14. Fragment Production in Non-central Collisions of Intermediate Energy Heavy Ions

    CERN Document Server

    Davin, B; Xu, H; Beaulieu, L; Larochelle, Y; Lefort, T; Yañez, R; Hudan, S; Caraley, A L; De Souza, R T; Liu, T X; Liu, X D; Lynch, W G; Shomin, R; Tan, W P; Tsang, M B; Molen, A V; Wagner, A; Xi Hong Fei; Gelbke, C K; Charity, R J; Sobotka, L G

    2002-01-01

    The defining characteristics of fragment emission resulting from the non-central collision of 114Cd ions with 92Mo target nuclei at E/A = 50 MeV are presented. Charge correlations and average relative velocities for mid-velocity fragment emission exhibit significant differences when compared to standard statistical decay. These differences associated with similar velocity dissipation are indicative of the influence of the entrance channel dynamics on the fragment production process.

  15. Effects of Ion-Ion Collisions and Inhomogeneity in Two-Dimensional Kinetic Ion Simulations of Stimulated Brillouin Backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B I; Divol, L; Langdon, A B; Williams, E A

    2005-10-17

    Two-dimensional simulations with the BZOHAR [B.I. Cohen, B.F. Lasinski, A.B. Langdon, and E.A. Williams, Phys. Plasmas 4, 956 (1997)] hybrid code (kinetic particle ions and Boltzmann fluid electrons) have been used to investigate the saturation of stimulated Brillouin backscatter (SBBS) instability including the effects of ion-ion collisions and inhomogeneity. Ion-ion collisions tend to increase ion-wave dissipation, which decreases the gain exponent for stimulated Brillouin backscattering; and the peak Brillouin backscatter reflectivities tend to decrease with increasing collisionality in the simulations. Two types of Langevin-operator, ion-ion collision models were implemented in the simulations. In both models used the collisions are functions of the local ion temperature and density, but the collisions have no velocity dependence in the first model. In the second model, the collisions are also functions of the energy of the ion that is being scattered so as to represent a Fokker-Planck collision operator. Collisions decorrelate the ions from the acoustic waves in SBS, which disrupts ion trapping in the acoustic wave. Nevertheless, ion trapping leading to a hot ion tail and two-dimensional physics that allows the SBS ion waves to nonlinearly scatter remain robust saturation mechanisms for SBBS in a high-gain limit over a range of ion collisionality. SBS backscatter in the presence of a spatially nonuniform plasma flow is also investigated. Simulations show that depending on the sign of the spatial gradient of the flow relative to the backscatter, ion trapping effects that produce a nonlinear frequency shift can enhance (auto-resonance) or decrease (anti-auto-resonance) reflectivities in agreement with theoretical arguments.

  16. Multiple electron capture in close ion-atom collisions

    International Nuclear Information System (INIS)

    Multiple electron capture is reported for Ca17+ in Ar. Close collisions are defined by the observation of a coincident Ca K or Ar K x-ray. A large number of electrons is transferred to the projectile in a single close collision when the Ca ion projectile is of the order of the Ar L-shell electron velocity. The cross section for electron capture is reported

  17. Directed flow in ultrarelativistic heavy-ion collisions

    OpenAIRE

    Bozek, Piotr; Wyskiel, Iwona

    2010-01-01

    We study the generation of directed flow in the hydrodynamic expansion of the hot matter formed in ultrarelativistic heavy-ion collisions at 200GeV. The experimentally observed negative directed flow in a wide range of central pseudorapidities isreproduced assuming that the fireball is tilted away from the collision axis. The tilt of the source is consistent with a preferential emission in the forward/backward hemisphere from forward/backward participating nucleons. The model reproduces the e...

  18. HEAVY ION COLLISIONS AND NEW FORMS OF MATTER

    Energy Technology Data Exchange (ETDEWEB)

    MCLERRAN,L.

    2007-07-02

    I discuss forms of high energy density matter in QCD. These include the Color Glass Condensate, the Glasma and the Quark Gluon Plasma. These all might be studied in ultra-relativistic heavy ion collisions, and the Color Glass Condensate might also be probed in electron-hadron collisions. I present the properties of such matter, and some aspects of what is known of their properties.

  19. Magneto optical trap recoil ion momentum spectroscopy: application to ion-atom collisions

    International Nuclear Information System (INIS)

    87Rb atoms have been cooled, trapped and prepared as targets for collision studies with 2 and 5 keV Na+ projectiles. The physics studied deals with charge exchange processes. The active electron, which is generally the most peripheral electron of the atomic target, is transferred from the target onto the ionic projectile. The ionized target is called recoil ion. The technique used to study this physics is the MOTRIMS (Magneto Optical Trap Recoil Ion Momentum Spectroscopy) technique, which combines a magneto optical trap and a recoil ion momentum spectrometer. The spectrometer is used for the measurement of the recoil ions momentum, which gives access to all the information of the collision: the Q-value (which is the potential energy difference of the active electron on each particle) and the scattering angle of the projectile. The trap provides extremely cold targets to optimize the measurement of the momentum, and to release the latter from thermal motion. Through cinematically complete experiments, the MOTRIMS technique gives access to better resolutions on momentum measurements. Measurements of differential cross sections in initial and final capture states and in scattering angle have been done. Results obtained for differential cross sections in initial and final states show globally a good agreement with theory and an other experiment. Nevertheless, discrepancies with theory and this other experiment are shown for the measurements of doubly differential cross sections. These discrepancies are not understood yet. The particularity of the experimental setup designed and tested in this work, namely a low background noise, allows a great sensitivity to weak capture channels, and brings a technical and scientific gain compared with previous works. (author)

  20. L electron populations of hollow ions produced in collisions of energetic Ar ions with metallic targets

    International Nuclear Information System (INIS)

    In this work, we studied hollow ions produced in collisions of Ar ions with metallic targets of atomic numbers 12 ∝ 73, at incident energies 43 ∝ 95 MeV. We observed Kα hypersatellites and satellites of Ar ions and obtained L shell electron populations with vacant and half vacant K shell. The results are very different to those reported for hollow atoms formed in slow collisions. (orig.)

  1. Eigenfrequencies of Ion-Acoustic Waves in the Presence of Electron-Ion Collisions

    Institute of Scientific and Technical Information of China (English)

    ZHEHG Jian; YU Chang-Xuan

    2000-01-01

    Frequencies and damping rate of ion-acoustic waves in the presence of electron-ion collisions are computed by reducing the linearized electron Fokker-Planck equation and cold-ion fluid equations to an eigenvalue equation via moment expansion of the perturbation of electron distribution function. As electrons becomes less collisional, a great number of Sonine modes are needed for convergence to a desired accuracy in the calculation, which may be ascribed to the neglected electron-electron collisions.

  2. A systematic study of the initial state in heavy ion collisions based on the quark participant assumption

    International Nuclear Information System (INIS)

    We investigate the initial state geometric quantities of heavy ion collisions based on the quark participant assumption in the Glauber multiple scattering approach. A systematic comparison to the nucleon participant assumption has been presented and confronted with the charged multiplicity measurements in various collision systems. It is found that the quark participant based assumption can be important to understand the data in multiplicity production and the initial spatial eccentricity in small systems. (orig.)

  3. Laser production of highly charged ions

    Czech Academy of Sciences Publication Activity Database

    Láska, Leoš; Badziak, J.; Boody, F. P.; Gammino, S.; Jungwirth, Karel; Krása, Josef; Pfeifer, Miroslav; Rohlena, Karel; Ullschmied, Jiří; Parys, P.; Wolowski, J.; Woryna, E.; Torrisi, L.

    2005-01-01

    Roč. 34, 4B (2005), s. 1615-1619. ISSN 0103-9733 R&D Projects: GA AV ČR(CZ) IAA1010105; GA MŠk(CZ) LN00A100 Grant ostatní: EU(Projects PALS/005 and PALS/006)(XE) HPRI-CT-1999-00053; INFN(IT) ECLISSE and PLAIA Institutional research plan: CEZ:AV0Z10100523 Keywords : laser ion generation * highly charged ions * laser beam self-focusing Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.445, year: 2005

  4. Electron collisions and internal excitation in stored molecular ion beams

    International Nuclear Information System (INIS)

    In storage ring experiments the role, which the initial internal excitation of a molecular ion can play in electron collisions, and the effect of these collisions on the internal excitation are investigated. Dissociative recombination (DR) and inelastic and super-elastic collisions are studied in the system of He+2. The DR rate coefficient at low energies depends strongly on the initial vibrational excitation in this system. Therefore changes in the DR rate coefficient are a very sensitive probe for changes in the vibrational excitation in He+2, which is used to investigate the effects of collisions with electrons and residual gas species. The low-energy DR of HD+ is rich with resonances from the indirect DR process, when certain initial rotational levels in the molecular ion are coupled to levels in neutral Rydberg states lying below the ion state. Using new procedures for high-resolution electron-ion collision spectroscopy developed here, these resonances in the DR cross section can be measured with high energy sensitivity. This allows a detailed comparison with results of a MQDT calculation in an effort to assign some or all of the resonances to certain intermediate Rydberg levels. (orig.)

  5. Electron collisions and internal excitation in stored molecular ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Buhr, H.

    2006-07-26

    In storage ring experiments the role, which the initial internal excitation of a molecular ion can play in electron collisions, and the effect of these collisions on the internal excitation are investigated. Dissociative recombination (DR) and inelastic and super-elastic collisions are studied in the system of He{sup +}{sub 2}. The DR rate coefficient at low energies depends strongly on the initial vibrational excitation in this system. Therefore changes in the DR rate coefficient are a very sensitive probe for changes in the vibrational excitation in He{sup +}{sub 2}, which is used to investigate the effects of collisions with electrons and residual gas species. The low-energy DR of HD{sup +} is rich with resonances from the indirect DR process, when certain initial rotational levels in the molecular ion are coupled to levels in neutral Rydberg states lying below the ion state. Using new procedures for high-resolution electron-ion collision spectroscopy developed here, these resonances in the DR cross section can be measured with high energy sensitivity. This allows a detailed comparison with results of a MQDT calculation in an effort to assign some or all of the resonances to certain intermediate Rydberg levels. (orig.)

  6. A theoretical model for electron transfer in ion-atom collisions: Calculations for the collision of a proton with an argon atom

    International Nuclear Information System (INIS)

    We have developed a theoretical model of ion-atom collisions based on the time-dependent density-functional theory. We solve the time-dependent Kohn-Sham equation for electrons employing the real-space and real-time method, while the ion dynamics are described in classical mechanics by the Ehrenfest method. Taking advantage of the real-space grid method, we introduce the 'coordinate space translation' technique to allow one to focus on a certain space of interest. Benchmark calculations are given for collisions between proton and argon over a wide range of impact energy. Electron transfer total cross sections showed a fairly good agreement with available experimental data. -- Highlights: → We have developed a theoretical model of ion-atom collisions based on TDDFT. → The coordinate space translation technique was introduced into present calculation. → Charge transfer cross sections showed a good agreement with available experimental data.

  7. Near-threshold photoionization of hydrogenlike uranium studied in ion-atom collisions via the time-reversed process.

    Science.gov (United States)

    Stöhlker, T; Ma, X; Ludziejewski, T; Beyer, H F; Bosch, F; Brinzanescu, O; Dunford, R W; Eichler, J; Hagmann, S; Ichihara, A; Kozhuharov, C; Krämer, A; Liesen, D; Mokler, P H; Stachura, Z; Swiat, P; Warczak, A

    2001-02-01

    Radiative electron capture, the time-reversed photoionization process occurring in ion-atom collisions, provides presently the only access to photoionization studies for very highly charged ions. By applying the deceleration mode of the ESR storage ring, we studied this process in low-energy collisions of bare uranium ions with low- Z target atoms. This technique allows us to extend the current information about photoionization to much lower energies than those accessible for neutral heavy elements in the direct reaction channel. The results prove that for high- Z systems, higher-order multipole contributions and magnetic corrections persist even at energies close to the threshold. PMID:11177990

  8. Study of central collisions of relativistic 12C and 40Ar on 208Pb, using neutral and charged pi-meson production, and charged particle multiplicity as probes. Volumes 1 and II

    International Nuclear Information System (INIS)

    Recent advances in accelerator technology have made it possible to accelerate nuclei much heavier than the proton to relativistic energies, opening the study of nuclear matter to a new and exciting avenue of scientific inquiry - the study of relativistic heavy ion collisions. To help expand the boundaries of current knowlege in this field, and to understand the detailed nature of the collision process more fully, the rate of charged and neutral pion production, the total charged particle multiplicity, and the production of low energy γ rays have been measured for central collisions relativistic 12C and 40Ar on 208Pb. Using the results of these measurements, an effort has been made to determine what phenomena may exist which are uniquely characteristic of central collisions of relativistic heavy ions, how central collisions of relativistic heavy ions may be parameterized, e.g., by charged particle multiplicity, so that future studies may be done more systematically, and how thoroughly the incident energy and momentum delivered by the projectile are distributed among the nucleons which participate in the reaction. Toward that end, the observations of the current study are compared with existing heavy ion collision theories whenever possible. The neutral pion production measurments presented in this work represent the first reported data of their kind, and consequently are of particular interest. Overall, the rate of both charged and neutral pion production is found to be a smoothly increasing function of beam energy

  9. Hydrodynamics in heavy-ion collisions: recent developments

    CERN Document Server

    Jaiswal, Amaresh

    2016-01-01

    Relativistic hydrodynamics has been quite successful in explaining the collective behaviour of the QCD matter produced in high energy heavy-ion collisions at RHIC and LHC. We briefly review the latest developments in the hydrodynamical modeling of relativistic heavy-ion collisions. Essential ingredients of the model such as the hydrodynamic evolution equations, dissipation, initial conditions, equation of state, and freeze-out process are reviewed. We discuss observable quantities such as particle spectra and anisotropic flow as well as the event-by-event fluctuations of these quantities. We also discuss the extraction of transport coefficients of the hot and dense QCD matter from the experimental data of collective flow.

  10. Electrons with continuous energy distribution from energetic heavy ion collisions

    International Nuclear Information System (INIS)

    The properties and origin of continuous electron spectrum emitted in high energy heavy ion collisions are reviewed. The basic processes causing the characteristic regions of the continuous spectrum are described. The contribution of electrons ejected from the target and from the projectile are investigated in detail in the cases of light and heavy projectiles. The recently recognized mechanisms, electron-capture-to-continuum (ECC) and electron-loss-to-continuum (ELC), leading to a cusp in forward direction, and their theoretical interpretations are discussed. The importance of data from ion-atom collisions in the field of atomic physics and in applications are briefly summarized. (D.Gy)

  11. Imaging of granular sources in high energy heavy ion collisions

    OpenAIRE

    Yang, Zhi-Tao; Zhang, Wei-Ning; Huo, Lei; Zhang, Jing-Bo

    2008-01-01

    We investigate the source imaging for a granular pion-emitting source model in high energy heavy ion collisions. The two-pion source functions of the granular sources exhibit a two-tiered structure. Using a parametrized formula of granular two-pion source function, we examine the two-tiered structure of the source functions for the imaging data of Au+Au collisions at Alternating Gradient Synchrotron (AGS) and Relativistic Heavy Ion Collider (RHIC). We find that the imaging technique introduce...

  12. Lambda-Lambda Correlation in Relativistic Heavy Ion Collisions

    Directory of Open Access Journals (Sweden)

    Morita Kenji

    2015-01-01

    Full Text Available We investigate Λ − Λ correlation function in relativistic heavy ion collisions to extract their interaction. Using an expanding source model for heavy ion collisions, we disentangle effects of collective expansion and those of the interaction at low relative momenta. Then, we discuss the influence of the feed-down correction for Σ0 decay and indicate the possible existence of a residual correlation at high relative momenta. Consequently, the present STAR data suggest a weakly attractive interaction for the ΛΛ pairs which is represented by the scattering length, 1/a0 < −0.8 fm−1.

  13. Progress in jet reconstruction and heavy ion collisions

    CERN Document Server

    Rojo, Juan

    2010-01-01

    We review recent developments related to jet clustering algorithms and jet reconstruction, with particular emphasis on their implications in heavy ion collisions. These developments include fast implementations of sequential recombination algorithms, new IRC safe algorithms, quantitative determination of jet areas and quality measures for jet finding, among many others. We also show how jet reconstruction provides a useful tool to probe the characteristics of the hot and dense medium created in heavy ion collisions, which allows one to distinguish between different models of parton-medium interaction.

  14. Complexified boost invariance and holographic heavy ion collisions

    CERN Document Server

    Gubser, Steven S

    2015-01-01

    At strong coupling holographic studies have shown that heavy ion collisions do not obey normal boost invariance. Here we study a modified boost invariance through a complex shift in time, and show that this leads to surprisingly good agreement with numerical holographic computations. When including perturbations the agreement becomes even better, both in the hydrodynamic and the far-from-equilibrium regime. One of the main advantages is an analytic formulation of the stress-energy tensor of the longitudinal dynamics of holographic heavy ion collisions.

  15. Two-pion correlations in heavy ion collisions

    International Nuclear Information System (INIS)

    An application of intensity interferometry to relativistic heavy ion collisions is reported. Specifically, the correlation between two like-charged pions is used to study the reactions Ar+KCl→2π/sup +-/+X and Ne+NaF→2π-+X. Source sizes are obtained that are consistent with a simple geometric interpretation. Lifetimes are less well determined but are indicative of a faster pion production process than predicted by Monte Carlo cascade calculations. There appears to be a substantial coherent component of the pion source, although measurement is complicated by the presence of final state interactions. Additionally, the generation of spectra of uncorrelated events is discussed. In particular, the influence of the correlation function on the background spectrum is analyzed, and a prescription for removal of this influence is given. A formulation to describe the statistical errors in the background is also presented. Finally, drawing from the available literature, a self-contained introduction to Bose-Einstein correlations and the Hanbury-Brown - Twiss effect is provided, with an emphasis on points of contact between classical and quantum mechanical descriptions

  16. Charge-state-dependent energy loss of slow ions. II. Statistical atom model

    Science.gov (United States)

    Wilhelm, Richard A.; Möller, Wolfhard

    2016-05-01

    A model for charge-dependent energy loss of slow ions is developed based on the Thomas-Fermi statistical model of atoms. Using a modified electrostatic potential which takes the ionic charge into account, nuclear and electronic energy transfers are calculated, the latter by an extension of the Firsov model. To evaluate the importance of multiple collisions even in nanometer-thick target materials we use the charge-state-dependent potentials in a Monte Carlo simulation in the binary collision approximation and compare the results to experiment. The Monte Carlo results reproduce the incident charge-state dependence of measured data well [see R. A. Wilhelm et al., Phys. Rev. A 93, 052708 (2016), 10.1103/PhysRevA.93.052708], even though the experimentally observed charge exchange dependence is not included in the model.

  17. Photoinduced Charge Separation in Porphyrin Ion Pairs.

    Science.gov (United States)

    Natali, Mirco; Scandola, Franco

    2016-03-10

    Ion pairs between porphyrin-type compounds have been successfully employed for spectral sensitization of semiconductor surfaces and for the preparation of collective binary ionic materials for photonic and (photo)catalytic applications. The understanding of the photophysical processes occurring within ion-paired porphyrin dimers is thus of remarkable importance for the optimization and improvement of such systems. Herein the ion-pair species formed between ZnTMePyP(4+) (Zn1) or H2TMePyP(4+) (H21) and ZnTPPS(4-) (Zn2) or H2TPPS(4-) (H22) in a variety of solvent mixtures are characterized and their photophysics thoroughly investigated by time-resolved techniques. In all the systems studied, very fast and efficient photoinduced charge separation is observed, with the cationic porphyrin being reduced and the anionic one oxidized. Interestingly, despite the very short charge separation distance, the lifetime for charge recombination, depending on the energy gap, can extend into the nanosecond time domain, showing great potential for the utilization of this molecular design within energy conversion schemes. PMID:26905260

  18. Inclusive Production of Charged Hadrons in Photon-Photon Collisions

    CERN Document Server

    Abbiendi, G; Åkesson, P F; Alexander, G; Anagnostou, G; Anderson, K; Asai, S; Axen, D; Bailey, I; Barberio, E; Barillari, T; Barlow, R; Batley, R; Bechtle, P; Behnke, T; Bell, K W; Bell, P; Bella, G; Bellerive, A; Benelli, G; Bethke, S; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R; Burckhart, H; Campana, S; Capiluppi, P; Carnegie, R; Carter, A; Carter, J; Chang, C; Charlton, D; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; de Roeck, A; De Wolf, E; Desch, K; Dienes, B; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I; Etzion, E; Fabbri, F; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, J; Gruwé, M; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Herten, G; Heuer, R D; Hill, J; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T; Kanzaki, J; Karlen, D; Kawagoe, K; Kawamoto, T; Keeler, R; Kellogg, R; Kennedy, B; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krasznahorkay, A; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Lafferty, G; Landsman, H; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A; Mashimo, T; Mättig, P; McKenna, J; McPherson, R; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H; Nisius, R; O'Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J; Pilcher, J E; Pinfold, J L; Plane, D; Pooth, O; Przybycien, M B; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J; Rossi, A; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A; Schaile, O; Scharff-Hansen, P; schiecks, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B; Sherwood, P; Skuja, A; Smith, A; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M; Torrence, E; Toya, D; Tran, P; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, Joost Herman; Ward, C; Ward, D; Watkins, P; Watson, A; Watson, N; Wells, P; Wengler, T; Wermes, N; Wilson, G; Wilson, J; Wolf, G; Wyatt, T; Yamashita, S; Zer-Zion, D; Zivkovic, L

    2007-01-01

    The inclusive production of charged hadrons in the collisions of quasi-real photons e+e- -> e+e- +X has been measured using the OPAL detector at LEP. The data were taken at e+e- centre-of-mass energies from 183 to 209 GeV. The differential cross-sections as a function of the transverse momentum and the pseudorapidity of the hadrons are compared to theoretical calculations of up to next-to-leading order (NLO) in the strong coupling constant alpha{s}. The data are also compared to a measurement by the L3 Collaboration, in which a large deviation from the NLO predictions is observed.

  19. ANISOTROPY EFFECTS IN SINGLE-ELECTRON TRANSFER BETWEEN LASER-EXCITED ATOMS AND HIGHLY-CHARGED IONS

    NARCIS (Netherlands)

    1995-01-01

    Recent collision experiments are reviewed in which one-electron transfer between laser excited target atoms and (highly charged) keV-ions has been studied. Especially results showing a dependence of the charge exchange on the initial target orbital alignment are discussed. The question to what exten

  20. Charge Exchange in Low-Energy H, D + C4+ Collisions with Full Account of Electron Translation

    Directory of Open Access Journals (Sweden)

    A. Riera

    2002-03-01

    Full Text Available The effect of the anisotropy of the interaction potential on ion-diatom non-adiabatic collisions is analized by considering the influence of the anisotropy on orientation averaged total cross sections for charge transfer in H++H2(X1Σ+g collisions. We discuss the possibility of employing simpli ed methods such as an isotropic approximation, where only the electronic energies and interactions of a single orientation are necessary. The use of several isotropic calculations to evaluate the orientation averaged cross section is analized.

  1. Multiply-charged ion emission from a cyclotron-resonance-heated plasma ion source

    International Nuclear Information System (INIS)

    Electron cyclotron resonance heated ion sources have become the prominent electron-stripping device used to produce multiply-charged ions. These ions are required for many applications ranging from atomic physics research to cyclotron injection. Unfortunately, many of these sources are designed, built and operated based on empirical knowledge acquired from past or existing machines. Much research remains to be performed before a solid understanding of the physical processes governing these sources can be gained. The work presented here attempts to partially bridge the gap between application and understanding. A time-of-flight spectrometer diagnostic system was implemented on MIMI to measure the endloss current density for specific charge states flowing from the mirror. The method of acquiring many spectra in a given shot over a relatively short span of real time, and averaging them to produce one averaged spectrum has proven quite effective in reducing random signal fluctuations. Also, shot-to-shot reproducibility becomes possible with this method -- a difficult and most welcome result. Ion cyclotron heating has been shown to increase ion temperatures tens of eV. The resonant species typically experiences the greatest temperature increase but transfers much of its energy to the remainder of the distribution via collisions. These temperature increases are consistent with those expected from antenna loading computations. Modeling of the important physical processes occurring in the plasma yields results consistent with those measured with the time-of-flight spectrometer. 62 refs., 68 figs., 9 tabs

  2. Initial state fluctuations and higher harmonic flow in heavy-ion collisions

    CERN Document Server

    Gale, Charles; Schenke, Bjoern; Tribedy, Prithwish; Venugopalan, Raju

    2012-01-01

    A framework combining Yang-Mills dynamics of the pre-equilibrium glasma with relativistic viscous hydrodynamic evolution of the quark-gluon plasma and hadron gas phases is presented. Event-by-event fluctuations of nucleon positions and color charges are taken into account, leading to negative binomial fluctuations of gluon multiplicities. Experimental anisotropic flow coefficients v2-v5 of charged hadron distributions in heavy-ion collisions at the Large Hadron Collider are well described. Furthermore, event-by-event distributions of v2, v3 and v4 measured by the ATLAS collaboration are reproduced.

  3. Initial state fluctuations and higher harmonic flow in heavy-ion collisions

    Science.gov (United States)

    Gale, Charles; Jeon, Sangyong; Schenke, Björn; Tribedy, Prithwish; Venugopalan, Raju

    2013-05-01

    A framework combining Yang-Mills dynamics of the pre-equilibrium glasma with relativistic viscous hydrodynamic evolution of the quark-gluon plasma and hadron gas phases is presented. Event-by-event fluctuations of nucleon positions and color charges are taken into account, leading to negative binomial fluctuations of gluon multiplicities. Experimental anisotropic flow coefficients v2 - v5 of charged hadron distributions in heavy-ion collisions at the Large Hadron Collider are well described. Furthermore, event-by-event distributions of v2,v3andv4 measured by the ATLAS collaboration are reproduced.

  4. Charge and Energy Dependences of Ionization and Transfer for Helium in Collisions with Fast Charged Projectiles

    Institute of Scientific and Technical Information of China (English)

    FU Hong-Bin; WANG Bao-Hong; DING Bao-Wei; LIU Zhao-Yuan

    2009-01-01

    The classical method within the independent electron model is employed to investigate (i) charge dependences of single and double ionization for helium by various charged ions Aq+ (q = 1 - 8) at impact energies of 0.64 and 1.44 MeV/u, respectively, (ii) energy dependences of transfer ionization for helium by 0.5-3 MeV/u A8,9+ ions impact. The Lenz-Jensen model of the atom is applied instead of the Bohr model of the atom, and the impact-parameter dependences are also introduced into the calculations. Satisfactory agreement is found between theoretical and experimental data.

  5. Lifetime Measurements of Highly Charged Ions

    Energy Technology Data Exchange (ETDEWEB)

    Traebert, E. [Ruhr-Univ. Bochum (Germany). Experimentalphysik III

    2002-08-01

    How long does an atom 'live' in an excited state, when due to conservation rules and symmetry principles the 'normal' electric dipole decay to the ground state is forbidden? Then spin-changing 'intercombination' transitions and electric dipole 'forbidden' decays occur that are important for the diagnostics of low-density solar corona] and terrestrial plasmas. Regular 'allowed' and intercombination transitions in highly charged ions (picosecond and nanosecond lifetime range) have previously been measured with straight, foil-excited, fast ion beams. For ions with only one or two electrons in the valence shell, very long sections of the isoelectronic sequence have been covered this way, yielding experimental tests of theoretical predictions of transition rates that are good to a few percent. Recently the situation has become much better than this for lifetimes in the millisecond range. Here the technique of optical observation at a heavy-ion storage ring permits atomic lifetime measurements on intercombination and forbidden transitions with a precision that often is better than 1 %, which is clearly surpassing the precision range of typical conventional ion trap data. The electron beam ion trap (EBIT) exhibits a similar precision in the 'X-ray' range, and it has reached uncertainties of a few percent in some measurements of optical transitions.

  6. Lifetime Measurements of Highly Charged Ions

    International Nuclear Information System (INIS)

    How long does an atom 'live' in an excited state, when due to conservation rules and symmetry principles the 'normal' electric dipole decay to the ground state is forbidden? Then spin-changing 'intercombination' transitions and electric dipole 'forbidden' decays occur that are important for the diagnostics of low-density solar corona] and terrestrial plasmas. Regular 'allowed' and intercombination transitions in highly charged ions (picosecond and nanosecond lifetime range) have previously been measured with straight, foil-excited, fast ion beams. For ions with only one or two electrons in the valence shell, very long sections of the isoelectronic sequence have been covered this way, yielding experimental tests of theoretical predictions of transition rates that are good to a few percent. Recently the situation has become much better than this for lifetimes in the millisecond range. Here the technique of optical observation at a heavy-ion storage ring permits atomic lifetime measurements on intercombination and forbidden transitions with a precision that often is better than 1 %, which is clearly surpassing the precision range of typical conventional ion trap data. The electron beam ion trap (EBIT) exhibits a similar precision in the 'X-ray' range, and it has reached uncertainties of a few percent in some measurements of optical transitions

  7. Radioactive decays of highly-charged ions

    Directory of Open Access Journals (Sweden)

    Gao B. S.

    2015-01-01

    Full Text Available Access to stored and cooled highly-charged radionuclides offers unprecedented opportunities to perform high-precision investigations of their decays. Since the few-electron ions, e.g. hydrogen- or helium-like ions, are quantum mechanical systems with clear electronic ground state configurations, the decay studies of such ions are performed under well-defined conditions and allow for addressing fundamental aspects of the decay process. Presented here is a compact review of the relevant experiments conducted at the Experimental Storage Ring ESR of GSI. A particular emphasis is given to the investigations of the two-body beta decay, namely the bound-state β-decay and its time-mirrored counterpart, orbital electron-capture.

  8. Intercombination lines in highly charged ions

    International Nuclear Information System (INIS)

    Experimental decay rates for the spin-forbidden ns2npk-1-nsnpk transitions in highly ionized Be-like, B-like, Mg-like and Al-like ions have been obtained by the beam-foil technique. Results are reported for Be-like and B-like Fe22+, Al-like Kr23+, Y26+ and Rh32+ and Mg-like Ni16+, Kr24+, Y27+ Zr28+, Nb29+ and Rh33+. For all ions in the Mg- and Al-like sequences the experimental oscillator strengths are larger than the theoretical predictions and, furthermore, the discrepancy tends to increase with increasing charge state. For both the Be- and B-like ions good agreement is found between theory and experiment. The experimental data presented here was obtained using the RILAC accelerator at RIKEN. (orig.)

  9. Charged particle multiplicities in nuclear collisions at 200 GeV/N

    International Nuclear Information System (INIS)

    Data on multiplicities of charged particles produced in proton-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon are presented. It is shown that the mean multiplicity of negative particles is proportional to the mean number of nucleons participating in the collision both for nucleus-nucleus and proton-nucleus collisions. The apparent consistency of pion multiplicity data with the assumption of an incoherent superposition of nucleon-nucleon collisions is critically discussed. (orig.)

  10. New results on Coulomb effects in meson production in relativistic heavy ion collisions

    Directory of Open Access Journals (Sweden)

    Rybicki Andrzej

    2014-01-01

    Full Text Available We propose a new method of investigating the space-time evolution of meson production in heavy ion collisions, by making use of spectator-induced electromagnetic (“Coulomb” effects. The presence of two nuclear remnants (“spectator systems” in the non-central collision generates a strong Coulomb field, which modifies the trajectories of charged final state hadrons. This results in charge-dependent azimuthal anisotropies in final state meson emission. In our approach, this effect can be computed numerically by means of a high-statistics Monte Carlo simulation, using the distance between the meson formation zone and the spectator system as free parameter. Our simulation correctly describes the electromagnetic effect on azimuthal anisotropies observed for π+ and π−mesons in Au+Au collisions at lower RHIC energy, known from data recently reported by the STAR Collaboration. Similarly to our earlier studies of spectator-induced electromagnetic effects, also in the present study we find that these effects offer sensitivity to the position of the meson formation zone with respect to the spectator system. Therefore, we conclude that they can serve as a new tool to investigate the space-time evolution of meson production, and the dynamics of the heavy ion collision.

  11. Extracting the symmetry energy information with heavy ion collisions

    International Nuclear Information System (INIS)

    Nuclear symmetry energy plays an important role in the properties of nuclei and neutron stars. Since theoretical predictions of the density dependence of symmetry energy S(ρ) from microscopic nucleon-nucleon interactions show large uncertainties, especially in the region of suprasaturation density, constraining the density dependence of symmetry energy has become one of the main goals in nuclear physics and has stimulated many theoretical and experimental studies. In this paper, we have reviewed the ImQMD05 code and its description on charge distribution, collective flow and nuclear-nuclear stopping. By comparing ImQMD05 prediction with data, the isoscalar part of nucleonic mean field, the energy and density dependence of in-medium NN cross sectoin in the ImQMD05 were determined. In order to extracting the symmetry energy information by comparing the ImQMD05 calculations with the data for 112,124Sn +112,124 Sn at Ebeam=50 MeV/u, the influence of symmetry potential and in-medium NN cross section on the isospin sensitive observables of intermediate-energy heavy-ion collisions was investigated. Focusing on the region above the Fermi energy, our results show that the symmetry potential plays a more important role in the experimental observables, such as double neutron to proton ratio and the isospin transport ratio Ri, than that the in-medium nucleon-nucleon cross section does. Since the copious production of intermediate mass fragments is a distinguishing feature of intermediate-energy heavy-ion collisions, we also examined the influence of cluster emission on the isospin transport ratio using different isospin tracers. The values of the isospin transport ratios with the tracer defined by the isospin asymmetry of the heaviest fragments with Z≥20 in the projectile region is greater than those obtained from projectile residues (emitting source). This phenomenon can be tested experimentally. By comparing the ImQMD05 predictions with the data for three observables, the

  12. Heavy ion collisions and anisotropic hydrodynamics

    International Nuclear Information System (INIS)

    A generalized hydrodynamical equation system was constructed in which the anisotropy of the momentum distribution is added as a new variable. These equations are derived from the moment equations of the relativistic Boltzmann equation where the closure of the set is achieved by assuming a particular class of initial conditions. The equations are then explicitly solved for two uniform interpenetrating hadron streams. The collision cross-sections are the bare hadron cross-sections; the presence of the other hadrons can be simulated by the use of a density and energy density dependent temperature and mass, taken from self-consistent calculations. The results are compared with other theoretical results. It was found that the isotropization occurs sufficiently rapidly for medium energy head-on collisions to reach local thermal equilibrium. (author)

  13. Electron capture to autoionizing states of multiply charged ions

    International Nuclear Information System (INIS)

    The present thesis investigates electron capture reactions resulting from slow collisions (V q+) and neutral gas targets (B). The energy spectra of the emitted electrons are measured; detection angle is 500. Mainly, autoionizing double capture resulting from collisions with two-electron targets (He, H2) is studied; then, the emitted electrons stem from doubly excited projectile states. The projectiles used are bare C6+, the H-like and He-like ions of C, N and O, He-like Ne8+ and Ne-like Ar8+. Excited metastable projectiles used are C5+(2s), He-like projectiles Aq+(1s2s3S) and Ar8+(...2p53s). Comparison is made with the predictions of a recently proposed extended classical barrier model, that was developed in connection with the work. This model assumes sequential capture of the electrons ('two-step' process); it predicts the realized binding enegies of the captured electrons - which may be directly determined from the autoionization spectra using only the projectile charge, the ionization potentials of the target and the collision velocity as parameters. No adjustable parameter enters into the calculations. The term energies and decay modes of the highly excited product ions themselves are studied. Generally, the autoionizing decay of these states is found to proceed preferentially to the directly adjacent lower singly excited state. Experimental evidence is presented, that triply excited states decay by successive emission of two electrons, whenever this is energetically possible. Finally, the L-MM decay in few-electron systems is considered. 314 refs.; 96 figs.; 29 tabs

  14. Formation of excited tin ion in collisions of slow electrons with SnCl2 molecules

    International Nuclear Information System (INIS)

    Formation of tin excited ions in collisions of slow electrons with tin dichloride molecules was studied experimentally. At electron energy of 100 eV 50 cross sections of excited single charged tin ions spectral lines were measured. 6 optical functions of dissociative excitation in the electron energy range of 0-100 eV were recorded. Comparison of cross sections for direct and dissociative excitation of certain lines was made. Dissociative excitation of spectral lines in two systems of SnCl molecules was studied simultaneously

  15. Jets and Vector Bosons in Heavy Ion Collisions

    Directory of Open Access Journals (Sweden)

    de la Cruz Begoña

    2013-11-01

    Full Text Available This paper reviews experimental results on jets and electroweak boson (photon,Wand Z production in heavy-ion collisions, from the CMS and ATLAS detectors, using data collected during 2011 PbPb run and pp data collected at an equivalent energy. By comparing the two collision systems, the energy loss of the partons propagating through the medium produced in PbPb collisions can be studied. Its characterization is done using dijet events and isolated photon-jet pairs. Since the electroweak gauge bosons do not participate in the strong interaction, and are thus unmodified by the nuclear medium, they serve as clean probes of the initial state in the collision.

  16. Time-evolution of many active electrons in slow ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Runge, K.; Micha, D.A.

    1996-05-01

    The previously developed Eikonal/Time-dependent Hartree-Fock method is applied to slow ionic and atomic collisions involving many active electrons. The electronic density matrix is written in a basis of traveling atomic orbitals including s, p, and d-type atomic basis functions. One- and two-electron integrals are calculated in a static basis and transformed to the traveling basis. Electronic orbital polarization parameters are calculated during the collision to determine the degree of electonic orientation and alignment as a function of time. This method is currently being applied to slow collisions of hydrogen, alkali, alkali earth and rare gas atoms and ions, to calculate the time evolution of electronic energy and charge transfer, as well as orbital polarization.

  17. Distorted wave collision strengths for n-n(prime) transitions in hydrogenic ions

    Science.gov (United States)

    Clark, R. E. H.

    1990-05-01

    Distorted wave collision strengths have been calculated for n-n(prime) transitions in hydrogenic ions with n-n(prime) of 3-4, 3-5, 5-6, 5-7, 7-8, and 7-9. Nuclear charge numbers Z were 3, 10, and 26. For each transition at each Z, the energies, in threshold units, were 1.01, 1.2, 1.5, 1.9, 2.5, 4.0, 6.0, 10.0 and 15.0. These collision strengths should be useful in testing various semiempirical formulas for electron impact excitation collision strengths needed in plasma modeling codes. Comparison is made with two such formulas.

  18. K-shell processes in heavy-ion collisions in solids and the local plasma approximation

    Science.gov (United States)

    Kadhane, Umesh; Montanari, C. C.; Tribedi, Lokesh C.

    2003-03-01

    We have investigated K-shell vacancy production due to ionization and electron transfer processes, in collisions of highly charged oxygen ions with various solid targets such as Cl, K, Ti, Fe, and Cu at energies between 1.5 and 6.0 MeV/u. The K-shell ionization cross sections were derived from the measured K x-ray cross sections. An ab initio theoretical model based on the local plasma approximation (LPA), which is an extension of the dielectric formalism to consider core electrons, provides an explanation of the measured data only qualitatively. In case of asymmetric collisions (Zp/Ztion-atom collisions agree quite well with the data for different combinations of target and projectile elements. In addition, we have also measured the K(target)-K(projectile) electron transfer cross sections and compared them with a model based on perturbed-stationary-state approximation.

  19. Charge-state evolution of highly charged ions transmitted through microcapillaries

    OpenAIRE

    Tokesi, K.; Wirtz, Ludger; Lemell, C.; Burgdorfer, J.

    2000-01-01

    The charge-state evolution of highly charged ions transmitted through microcapillaries is studied theoretically by a classical trajectory Monte Carlo simulation.: The interaction of highly charged ions with the internal surface of the capillary is treated within the framework of dielectric response theory. We analyze the distance of closest approach and the angular distributions of the highly charged ions at the exit of the microcapillary. We find the charge-state fraction of transmitted N6+ ...

  20. Two-body transport theory of heavy ion collisions

    International Nuclear Information System (INIS)

    The Two-body Correlation Transport Theory (TBCTT), its several hierarchy truncations and conservation laws for intermediate energy heavy ion collision have been investigated. This approach contains time-dependent mean field, two-body correlation effects and Pauli principle, the self-consistent coupling between time-dependent mean field and two body correlation dynamics is emphasized and preserved in realistic numerical calculation by a set of coupled dynamical equations. At the same time, in order to test our model and simplify numerical calculations, the authors employ the QMD code and neglect its collision term to produce the time-dependent coherent single particle basis. The preliminary numerical results show that TBCTT is a promising model for describing the dynamical process of heavy ion collisions

  1. Particle-production mechanism in relativistic heavy-ion collisions

    CERN Document Server

    Bush, B W; Brian W Bush

    1994-01-01

    We discuss the production of particles in relativistic heavy-ion collisions through the mechanism of massive bremsstrahlung, in which massive mesons are emitted during rapid nucleon acceleration. This mechanism is described within the framework of classical hadrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach to relativistic heavy-ion collisions that includes automatically spacetime nonlocality and retardation, nonequilibrium phenomena, interactions among all nucleons, and particle production. Inclusion of the finite nucleon size cures the difficulties with preacceleration and runaway solutions that have plagued the classical theory of self-interacting point particles. For the soft reactions that dominate nucleon-nucleon collisions, a significant fraction of the incident center-of-mass energy is radiated through massive bremsstrahlung. In the present version of the theory, this rad...

  2. Charge-dependent directed flow in asymmetric nuclear collisions

    CERN Document Server

    Voronyuk, V; Voloshin, S A; Cassing, W

    2014-01-01

    The directed flow of identified hadrons is studied within the parton-hadron-string-dynamics (PHSD) approach for the asymmetric system Cu+Au in non-central collisions at $\\sqrt{s_{NN}}$ = 200 GeV. It is emphasized that due to the difference in the number of protons of the colliding nuclei an electric field emerges which is directed from the heavy to the light nucleus. This strong electric field is only present for about 0.25 fm/c at $\\sqrt{s_{NN}}$ = 200 GeV and leads to a splitting of the directed flow $v_1$ for particles with the same mass but opposite electric charges in case of an early presence of charged quarks and antiquarks. The microscopic calculations of the directed flow for $\\pi^\\pm, K^\\pm, p$ and $\\bar{p}$ are carried out in the PHSD by taking into account the electromagnetic field induced by the spectators as well as its influence on the hadronic and partonic quasiparticle trajectories. It is shown that the splitting of the directed flow as a function of pseudorapidity $\\eta$ and in particular as...

  3. Soft electromagnetic radiations from relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Photons and dileptons have long been considered as excellent probes of quark-gluon plasma (QGP) expected to be formed in relativistic heavy ion collisions. To evaluate soft photons and dileptons from quark matter as well as soft photon approximation (SPA) is applied. The estimations of soft electromagnetic radiations that exists in the literature have certain discrepancies and efforts were made to correct them

  4. Electron and molecular ion collisions relevant to divertor plasma

    International Nuclear Information System (INIS)

    We introduce the concept of the multi-channel quantum defect theory (MQDT) and show the outline of the MQDT newly extended to include the dissociative states. We investigate some molecular processes relevant to the divertor plasma by using the MQDT: the dissociative recombination, dissociative excitation, and rotation-vibrational transition in the hydrogen molecular ion and electron collisions. (author)

  5. Inner-shell ionization in heavy ion collisions

    International Nuclear Information System (INIS)

    In this thesis the inner-shell ionization of heavy quasimolecular systems (U-U- and Pb-Pb systems) induced by heavy ion collisions is investigated. A coupled channel treatment of the many particle Schroedinger equation leads to predictions of the probability for K-shell ionization and of total ionization cross sections, which are compared with experimental results. (FKS)

  6. Heavy quark production in ultraperipherical heavy ion collisions

    International Nuclear Information System (INIS)

    We report our investigation in photonuclear production of heavy quarks in ultraperipherical heavy ion collisions. The charm and bottom cross section are computed employing sound high energy QCD formalisms: the usual collinear approach, the semihard formalism, the saturation model and the color glass condensate (CGC) formalism. (author)

  7. Reconstruction of the Proton Source in Relativistic Heavy Ion Collisions

    OpenAIRE

    Polleri, Alberto; Mattiello, Raffaele; Mishustin, Igor; Bondorf, Jakob

    1999-01-01

    We describe a direct method to reconstruct the transverse proton source formed in a relativistic heavy ion collision, making use of experimentally measured proton and deuteron spectra and assuming that deuterons are formed via two-nucleon coalescence. We show that an ambiguity with respect to the source temperature still persists and we indicate a possible solution to the problem.

  8. What is the temperature in heavy ion collisions?

    OpenAIRE

    Biro, T. S.; Purcsel, G.; Muller, B.

    2004-01-01

    We consider the Tsallis distribution as the source of the apparent slope of one-particle spectra in heavy-ion collisions and investigate the equation of state of this special quark matter in the framework of non-extensive thermodynamics.

  9. Coherent Pion Pairs from Heavy-Ion Collisions

    OpenAIRE

    Pratt, Scott; Haglin, Kevin

    1996-01-01

    The degree to which a nucleus can act as a source for coherent pion pairs is investigated for intermediate-energy heavy-ion collisions. Creation through both isovector and isoscalar channels is considered. Two experimental signals are proposed for evidence of two-pion coherent production, two-pion enhancement and the focusing of outgoing pions along the beam axis.

  10. Direct hadron production in ultrarelativistic heavy ion collisions

    OpenAIRE

    Peressounko, D. Yu.; Pokrovsky, Yu. E.

    1997-01-01

    Hadrons emitted by the pre-surface layer of quark-gluon plasma (QGP) before phase transition into hadronic gas are considered as possible source of direct information about QGP. It is shown that these hadrons dominate at soft p_t if QGP is created in ultrarelativistic heavy ion collisions.

  11. Electron emission in collisions of intermediate energy ions with atoms

    International Nuclear Information System (INIS)

    The aim of this work, is the analysis of the processes of electronic emission produced in the collisions of small ions (H+, He++) of intermediate energy (50 a 200 KeV/amu) with light gaseous targets. (A.C.A.G.)

  12. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions. Updated 1997

    Energy Technology Data Exchange (ETDEWEB)

    Tawara, H.

    1997-04-01

    Following our previous compilations (IPPJ-AM-45 (1986), NIFS-DATA-7 (1990), NIFS-DATA-20 (1993)), bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1954-1996 are listed in the order of the publication year. For easy finding of the references for a combination of collision partners, a simple list is provided. (author)

  13. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions. Updated 1997

    International Nuclear Information System (INIS)

    Following our previous compilations (IPPJ-AM-45 (1986), NIFS-DATA-7 (1990), NIFS-DATA-20 (1993)), bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1954-1996 are listed in the order of the publication year. For easy finding of the references for a combination of collision partners, a simple list is provided. (author)

  14. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions, updated 1990

    International Nuclear Information System (INIS)

    Following a previous compilation, new bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1989 are surveyed. For easy finding references for particular combination of collision partners, a simple list is also provided. Furthermore, for convenience, a copy of the previous compilation (IPPJ-AM-45 (1986)) is included. (author) 1363 refs

  15. Transverse energy and multiplicity from heavy ion collisions at 200 A GeV

    International Nuclear Information System (INIS)

    The successful acceleration of light ions at the CERN SPS and at the Brookhaven AGS opened the exciting field of ultra-relativistic heavy ion collisions for systematic studies. The first experiments were designed mainly to survey the reactions and to establish the essential features of the collisions. In this paper results from the WA80 experiment on transverse energy and charged particle multiplicity are reported. These two quantities are determined by most of the experiments and can be used to characterize the events. Large multiplicities and large transverse energies are correlated with violet collisions or with small impact parameters. In addition, an estimate of the energy density reached in the collision can be derived from those two measurements. One would like to know if the energy density necessary for the transition to the quark gluon plasma has been reached. The results of the first round of experiments with oxygen ions at 60 and 200 GeV per nucleon are collected in the proceedings of the Quark Matter 88 Conference. Some of these results are summarized here together with new results on multiplicity fluctuations

  16. Precision mass measurements of highly charged ions

    Science.gov (United States)

    Kwiatkowski, A. A.; Bale, J. C.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Lennarz, A.; Mane, E.; MacDonald, T. D.; Schultz, B. E.; Simon, M. C.; Simon, V. V.; Dilling, J.

    2012-10-01

    The reputation of Penning trap mass spectrometry for accuracy and precision was established with singly charged ions (SCI); however, the achievable precision and resolving power can be extended by using highly charged ions (HCI). The TITAN facility has demonstrated these enhancements for long-lived (T1/2>=50 ms) isobars and low-lying isomers, including ^71Ge^21+, ^74Rb^8+, ^78Rb^8+, and ^98Rb^15+. The Q-value of ^71Ge enters into the neutrino cross section, and the use of HCI reduced the resolving power required to distinguish the isobars from 3 x 10^5 to 20. The precision achieved in the measurement of ^74Rb^8+, a superallowed β-emitter and candidate to test the CVC hypothesis, rivaled earlier measurements with SCI in a fraction of the time. The 111.19(22) keV isomeric state in ^78Rb was resolved from the ground state. Mass measurements of neutron-rich Rb and Sr isotopes near A = 100 aid in determining the r-process pathway. Advanced ion manipulation techniques and recent results will be presented.

  17. Strangeness production in heavy ion collisions -Constraining the KN – potential in medium

    International Nuclear Information System (INIS)

    We review the strangeness production in heavy ion collisions at energies around the NN production threshold and discuss recent measurements of the FOPI collaboration on charged kaon flow over a wide impact parameter range. The data are compared to comprehensive state-of-the-art transport models. The dense nuclear matter environment produced in those collisions may provide unique opportunities to form strange few body systems. The FOPI detector is especially suited to reconstruct such states by their charged particle decays. Apart from strongly decaying states special emphasis will be put on the search for long living weakly decaying states, i.e. Hyper-Nuclei. Light hyper nuclei are reconstructed by their two body decay channels and the production of Hyper-Tritons is studied with respect to Λ and t(3He).

  18. Strangeness production in heavy ion collisions -Constraining the KN - potential in medium

    Science.gov (United States)

    Leifels, Yvonne; FOPI Collaboration

    2013-03-01

    We review the strangeness production in heavy ion collisions at energies around the NN production threshold and discuss recent measurements of the FOPI collaboration on charged kaon flow over a wide impact parameter range. The data are compared to comprehensive state-of-the-art transport models. The dense nuclear matter environment produced in those collisions may provide unique opportunities to form strange few body systems. The FOPI detector is especially suited to reconstruct such states by their charged particle decays. Apart from strongly decaying states special emphasis will be put on the search for long living weakly decaying states, i.e. Hyper-Nuclei. Light hyper nuclei are reconstructed by their two body decay channels and the production of Hyper-Tritons is studied with respect to Λ and t(3He).

  19. Single electron capture in collisions of Nq+ (q =5, 6, 7)ions with helium

    Institute of Scientific and Technical Information of China (English)

    Wang Fei; Wang Miao-Miao

    2011-01-01

    Close-coupling calculations are carried out for cross sections of the single electron capture in collisions of Nq+(q=5,6,7) ions with helium atoms in the collision velocity range from 0.3 a.u.to 1.8 a.u.The relative importances of the single ionization (SI) to the single capture (SC) are investigated for the Nq+(q =5,6,7) projectiles,respectively.The SI/SC cross section ratio for the N7+ projectile obtained from our calculations is in excellent agreement with the experimental data.The ratio curves also show us distinct behaviours when the charge of the projectile is different.The partial electron capture cross sections for different projectiles indicate that the electron on the target He atom tends to be captured by the projectile into its lower orbital of the outer shell with the decreasing projectile charge.

  20. Head-on collision of dust-ion-acoustic solitons in electron-dust-ion quantum plasmas

    Indian Academy of Sciences (India)

    Prasanta Chatterjee; Malay Kumar Ghorui; Rajkumar Roychoudhury

    2013-03-01

    In this paper, we study the head-on collision between two dust-ion-acoustic (DIA) solitons in quantum electron-dust-ion plasma. Using the extended Poincaré–Lighthill–Kuo (PLK) method, we obtain the Korteweg–de Vries (KdV) equations, the phase shifts and the trajectories after the head-on collision of the two DIA solitons. We investigate the effect of quantum diffraction parameters for electrons and ions $(H_{e}, H_{i})$, the Fermi temperature ratio () and the dust charged number density (d0) on the phase shifts. Different values of = d0(d0/i0) and d = d0(i/d) are taken to discuss the effects on phase shifts, where d0 denotes the dust charge number, j0 represents the equilibrium number density and is the mass of the jth species ( = , , for electrons, ions and dust particles, respectively). It is observed that the phase shifts are significantly affected by the plasma parameters.

  1. Diagonal and off-diagonal susceptibilities of conserved quantities in relativistic heavy-ion collisions

    CERN Document Server

    Chatterjee, Arghya; Nayak, Tapan K; Sahoo, Nihar Ranjan

    2016-01-01

    Susceptibilities of conserved quantities, such as baryon number, strangeness and electric charge are sensitive to the onset of quantum chromodynamics (QCD) phase transition and are expected to provide information on the matter produced in heavy-ion collision experiments. A comprehensive study of the second-order diagonal susceptibilities and cross correlations has been made within a thermal model approach of the hadron resonance gas (HRG) model as well as with a hadronic transport model, UrQMD. We perform a detailed analysis of the effect of detector acceptances and choice of particle species in the experimental measurements of the susceptibilities for heavy-ion collisions corresponding to \\sNN = 4 GeV to 200 GeV. The transverse momentum cutoff dependence of suitably normalised susceptibilities are proposed as useful observables to probe the properties of the medium at freezeout.

  2. Probing the nuclear equation-of-state and the symmetry energy with heavy-ion collisions

    Directory of Open Access Journals (Sweden)

    Verde Giuseppe

    2014-03-01

    Full Text Available The present status of studies aimed at constraining the nuclear equation of state with heavy-ion collision dynamics is presented. Multifragmentation phenomena, including their isotopic distributions, charge correlations and emission time-scales, may revel the existence of liquid-gas transitions in the phase diagram. Exploring the isotopic degree of freedom in nuclear dynamics is then required in order to constrain the equation of state of asymmetric nuclear matter which presently represents a major priority due to its relevance to both nuclear physics and astrophysics. Some observables that have successfully constrained the density dependence of the symmetry energy are presented, such as neutron-proton yield ratios and isospin diffusion and drift phenomena. The reported results and status of the art is discussed by also considering some of the present problems and some future perspectives for the heavy-ion collision community.

  3. An independent-atom-model description of ion-molecule collisions including geometric screening corrections

    Science.gov (United States)

    Lüdde, Hans Jürgen; Achenbach, Alexander; Kalkbrenner, Thilo; Jankowiak, Hans-Christian; Kirchner, Tom

    2016-04-01

    A new model to account for geometric screening corrections in an independent-atom-model description of ion-molecule collisions is introduced. The ion-molecule cross sections for net capture and net ionization are represented as weighted sums of atomic cross sections with weight factors that are determined from a geometric model of overlapping cross section areas. Results are presented for proton collisions with targets ranging from diatomic to complex polyatomic molecules. Significant improvement compared to simple additivity rule results and in general good agreement with experimental data are found. The flexibility of the approach opens up the possibility to study more detailed observables such as orientation-dependent and charge-state-correlated cross sections for a large class of complex targets ranging from biomolecules to atomic clusters.

  4. Probing the nuclear equation-of-state and the symmetry energy with heavy-ion collisions

    International Nuclear Information System (INIS)

    The present status of studies aimed at constraining the nuclear equation of state with heavy-ion collision dynamics is presented. Multifragmentation phenomena, including their isotopic distributions, charge correlations and emission time-scales, may revel the existence of liquid-gas transitions in the phase diagram. Exploring the isotopic degree of freedom in nuclear dynamics is then required in order to constrain the equation of state of asymmetric nuclear matter which presently represents a major priority due to its relevance to both nuclear physics and astrophysics. Some observables that have successfully constrained the density dependence of the symmetry energy are presented, such as neutron-proton yield ratios and isospin diffusion and drift phenomena. The reported results and status of the art is discussed by also considering some of the present problems and some future perspectives for the heavy-ion collision community. (authors)

  5. Rencontres de Moriond QCD 2012: Probing the nature of heavy-ion collisions

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    Wednesday began with presentations by experiments worldwide on their investigations into the intriguing nature of the Quark Gluon Plasma (QGP). The ALICE Collaboration examined further preliminary results from the LHC’s 2010 Pb-Pb run, observing that particles containing strange quarks were more abundant than they are in proton-proton collisions – indicating the presence of QGP. They also presented results from the so-called “soft probes” that allow scientists to look at the collective behaviour of the QGP medium.  The ATLAS and CMS Collaborations provided a very different approach to the study heavy ion physics: examining particle energy loss in the QGP by looking at the momentum of particle jets leaving the medium. ATLAS reported their results on a variety of studies using jets, charged hadrons and weak bosons produced in heavy-ion collisions during the 2010 run. Presenting their results from the 2011 run, the CMS Collaboration found that there is energy...

  6. Proposed precision laser spectrometer for trapped, highly charged ions

    OpenAIRE

    M. Vogel; Winters, D.F.A.; Segal, D. M.; Thompson, R. C.

    2005-01-01

    We propose a novel type of precision laser spectrometer for trapped, highly charged ions nearly at rest. It consists of a cylindrical open-endcap Penning trap in which an externally produced bunch of highly charged ions can be confined and investigated by means of laser spectroscopy. The combination of confinement, cooling and compression of a dense ion cloud will allow the ground state hyperfine splitting in highly charged ions to be measured with an accuracy three orders of magnitude better...

  7. Determination of charge state characteristics of selected scattered ions using a multiple thin film detector arrangement

    International Nuclear Information System (INIS)

    A nuclear charged particle detector has been designed which consists of a stack of three Thin Film Detectors (TFD), measuring the specific luminescence of the transiting ion, and a terminal surface barrier detector measuring the residual energy. To test the response of this detector, an experiment was performed in which several isotopes of germanium and selenium were scattered off a gold target and collimated through the detector assembly. The energies of the scattered ions ranged from 0.65 MeV/amu to 2 MeV/amu, bracketing the peak of the stopping power curve of the ions. An improved nuclear charge resolution is seen when using the multiple TFD arrangement. The analysis of the data also shows new information on the characteristics of the charge states of the ions scattered in small impact parameter collisions with the gold target nuclei

  8. Electromagnetic effects on meson production: a new tool for studying the space-time evolution of heavy ion collisions

    CERN Document Server

    Rybicki, Andrzej; Klusek-Gawenda, Mariola; Davis, Nikolaos; Ozvenchuk, Vitalii; Kielbowicz, Miroslaw

    2016-01-01

    We review our studies of spectator-induced electromagnetic (EM) effects on the emission of charged mesons in the final state of ultrarelativistic heavy ion collisions. We argue that these effects offer sensitivity to the distance $d_E$ between the charged meson formation zone at freeze-out and the spectator system. As such, the can serve as an independent, new tool to probe the space time evolution and longitudinal of the system created in the collision. As a phenomenological application for this tool in the context of resonance production and decay, we obtain a first estimate of the pion decoupling time from EM effects.

  9. Atomic collisions with 33-TeV lead ions

    International Nuclear Information System (INIS)

    Recent availability of relativistic and ultrarelativistic beams of heavy ions has permitted the first controlled studies of atomic collisions at energies sufficient to measure effects of several new basic phenomena. These include measurements substantiating recently predicted finite nuclear size effects resulting in a reduction in the total electronic energy loss of heavy ions in matter, and measurements of Coulomb collisions in which electrons are excited from the Dirac negative energy continuum. Measurements of total energy loss, free electron-positron pair production, and electron capture from pair production have been recently performed using 33-TeV Pb82+ ions from the CERN SPS accelerator in Geneva. Results of these studies are presented, along with comparisons with relevant theory

  10. Investigation of ion-atom collision dynamics through imaging techniques

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The principle and technique details of recoil ion momentum imaging are discussed and summarized. The recoil ion momentum spectroscopy built at the Institute of Modern Physics (Lanzhou) is presented. The first results obtained at the setup are analyzed. For 30 keV He2+ on He collision, it is found that the capture of single electron occurs dominantly into the first excited states, and the related scattering angle results show that the ground state capture occurs at large impact parameters, while the capture into excited states occurs at small impact parameters. The results manifest the collision dynamics for the sub-femto-second process can be studied through the techniques uniquely. Finally, the future possibilities of applications of the recoil ion momentum spectroscopy in other fields are outlined.

  11. Excitation and Fragmentation Mechanisms in Ion-Fullerene Collisions

    International Nuclear Information System (INIS)

    Electronic and vibronic excitations as well as fragmentation mechanisms in high energy ion (H+ , C+ , Ar+ ) fullerene collisions are investigated within a fully microscopic approach, called nonadiabatic quantum molecular dynamics. The total kinetic energy loss of the projectile depends dramatically on ion mass, but, surprisingly, does not depend on the impact velocity for all ions in a certain range. This is in striking contrast to the predictions of the 'stopping power' concept of solids, but explains apparently contradicting experimental observations. Signatures for nonstatistical fragmentation mechanisms are predicted

  12. Soft x-ray spectra and collisional ionization equilibrium of iron ions with data upgrade of electron–ion collisions

    Science.gov (United States)

    Liang, G. Y.; Wei, H. G.; Zhao, G.; Zhong, J. Y.

    2016-06-01

    Line emissivities and ionic fraction in (non-)equilibrium are crucial for understanding the x-ray and extreme ultraviolet (EUV) spectra. These emission originate from electron-impact excitations for a level population of highly charged ions in coronal-like plasma. Recently, a large amount of excitation data was generated within the R-matrix framework by the computational atomic physics community, especially the UK APAP network. These data take resonances in electron–ion collisions into account appropriately, which enhances the effective excitation rates and also the line emissivities in x-ray and EUV regions. For ionization equilibrium data, the earlier compilation by Mazzotta et al (1998 Astron. Astrophys. Supp. Ser. 133 403) was used extensively by the astronomical community until the update by Bryans et al (2006 Astrophys. J. Supp. Ser. 167 343), as well as the compilation of Dere (2007 Astron. Astrophys. 466 771) for electron-impact ionization rates. In past years, many experimental measurements have been performed of highly charged iron ions in heavy-ion storage ring facilities. In this work, we will investigate the line emissivities and ionization equilibrium of highly charged iron ions by using recent theoretical or experimental data of electron-impact excitations and ionizations.

  13. Charmonia and open charm production in heavy ion collisions

    CERN Document Server

    Gonin, Michel

    2005-01-01

    The production of heavy flavours in heavy ion collisions has been of great interest since the prediction of Matsui and Satz regarding quarkonium suppression in the quark gluon plasma due to color screening mechanisms. The NA50 collaboration has produced the first charmonia measurements in heavy ion collisions which show evidence for strong and anomalous suppressions in central Pb-Pb collisions. For the suppression of bound state quark-antiquark pairs to be a plasma signature, the production of these quarks inside the cold nucleus should first be well known. Differences in the relative yield of heavy flavour between nucleon-nucleon an nucleon-nucleus collisions probes cold nuclear matter effects such as the modifications of the gluon distribution functions or parton energy loss. The gluon-gluon fusion represents the dominant mechanism for the production of quarkonia studied by the heavy ion experiments. The purpose of this presentation is to highlight the latest results from the CERN-SPS and Fermilab fixed tar...

  14. Transverse Momentum Distributions of Charged Particles in Nuclear Collisions at RHIC Energies

    International Nuclear Information System (INIS)

    The paper reports on measurements of the transverse momentum distributions of produced particles from nuclear collisions at the highest center-of-mass energies provided by the Relativistic Heavy Ion Collider (RHIC). The transverse momentum spectra of charged hadrons produced in d + Au and Au + Au collisions at the top RHIC energy of 200 GeV in the nucleon-nucleon center-of-mass system are presented. For the Au + Au system, the measurements at the lower energy of 62.4 GeV are also reported. The analyzed data were collected by the PHOBOS experiment during several RHIC data-taking runs from 2001 to 2004. The main emphasis of this paper is the measurement of particle production at very low transverse momenta, a possibility uniquely available to the PHOBOS detector. A new non-standard method was developed to extract yields of (π+ + π-), (K+ + K-) and (p + p(bar)) at the lowest transverse momentum values accessible at RHIC. The results do not confirm the prediction of a significant enhancement in particle production at very low pT . The flattening of proton and antiproton pT spectra, consistent with the expectations of transverse expansion of the system, is clearly observed down to very low pT . In contrast to Au + Au collisions, such a flattening is not observed in yields of d + Au collisions at √sNN = 200 GeV. The scaling properties of mT spectra in Au + Au and d + Au collisions, as well as particle ratios, are discussed. Results obtained from the analysis of the transverse momentum distributions clearly show that the matter produced in nuclear collisions at RHIC energies is strongly coupled and undergoes a rapid transverse expansion. Comparison to the predictions of different models aiming to describe particle production in ultra-relativistic nuclear collisions is discussed. The characteristics of the system derived from this study of the transverse momentum distributions has provided a significant contribution to the RHIC discovery of a new state of matter, a

  15. Dynamical fission following peripheral heavy-ion collisions

    Science.gov (United States)

    Strazzeri, A.; Italiano, A.

    2016-02-01

    A closed-form theoretical approach describing in a single picture both the evaporation component and the fast nonequilibrium component of the sequential fission of projectile-like fragments in a peripheral heavy-ion collision is derived and then applied to the dynamical fission observed in the 124Sn+64Ni semiperipheral collision at 35AMeV. Information on the reaction mechanism is obtained such as the opposite polarization effects and the estimate of the “formation-to-fast fission lifetimes” of the fissioning fragment.

  16. Correlations of neutral pions in ultrarelativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Correlations of 4 photons representing neutral pions have been studied in ultrarelativistic heavy ion collisions. Data were taken in the WA80 experiment at the CERN-SPS with a 200 A GeV oxygen beam. The π0 are detected via their decay photons with a high-granularity lead glass array. Special features of interferometry using neutral pions will be discussed. The extracted preliminary parameters for high pT pions emitted near midrapidity in O+Au collisions lead to rather small effective source sizes. (orig.)

  17. Atomic Bremsstrahlung in ion-atom collisions (stripping)

    International Nuclear Information System (INIS)

    Atomic Bremsstrahlung produced in high energy (non relativistic) ion-atom collisions including retardation effects is studied. Mechanical states of the system are described by the symmetrical eikonal approximation and Hartree-Fock electronic wave functions for the calculation of the shape factor of each atom. Photon energy spectra are presented for collisions of protons against noble gases, Ne, Ar, Kr and Xe. The contribution of each atomic shell to these spectra is studied, where lowest shell (1s) corresponds to the hard X-ray region and the higher shells correspond to lower photon energies. (Author)

  18. Anisotropic Flow of Charged Particles in Pb-Pb Collisions at √[s{NN}]=5.02 TeV.

    Science.gov (United States)

    Adam, J; Adamová, D; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, S U; Aiola, S; Akindinov, A; Alam, S N; Albuquerque, D S D; Aleksandrov, D; Alessandro, B; Alexandre, D; Alfaro Molina, R; Alici, A; Alkin, A; Almaraz, J R M; Alme, J; Alt, T; Altinpinar, S; Altsybeev, I; Alves Garcia Prado, C; Andrei, C; Andronic, A; Anguelov, V; Antičić, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arcelli, S; Arnaldi, R; Arnold, O W; Arsene, I C; Arslandok, M; Audurier, B; Augustinus, A; Averbeck, R; Azmi, M D; Badalà, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bala, R; Balasubramanian, S; Baldisseri, A; Baral, R C; Barbano, A M; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartalini, P; Barth, K; Bartke, J; Bartsch, E; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batista Camejo, A; Batyunya, B; Batzing, P C; Bearden, I G; Beck, H; Bedda, C; Behera, N K; Belikov, I; Bellini, F; Bello Martinez, H; Bellwied, R; Belmont, R; Belmont-Moreno, E; Belyaev, V; Benacek, P; Bencedi, G; Beole, S; Berceanu, I; Bercuci, A; Berdnikov, Y; Berenyi, D; Bertens, R A; Berzano, D; Betev, L; Bhasin, A; Bhat, I R; Bhati, A K; Bhattacharjee, B; Bhom, J; Bianchi, L; Bianchi, N; Bianchin, C; Bielčík, J; Bielčíková, J; Bilandzic, A; Biro, G; Biswas, R; Biswas, S; Bjelogrlic, S; Blair, J T; Blau, D; Blume, C; Bock, F; Bogdanov, A; Bøggild, H; Boldizsár, L; Bombara, M; Book, J; Borel, H; Borissov, A; Borri, M; Bossú, F; Botta, E; Bourjau, C; Braun-Munzinger, P; Bregant, M; Breitner, T; Broker, T A; Browning, T A; Broz, M; Brucken, E J; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bufalino, S; Buncic, P; Busch, O; Buthelezi, Z; Butt, J B; Buxton, J T; Cabala, J; Caffarri, D; Cai, X; Caines, H; Calero Diaz, L; Caliva, A; Calvo Villar, E; Camerini, P; Carena, F; Carena, W; Carnesecchi, F; Castillo Castellanos, J; Castro, A J; Casula, E A R; Ceballos Sanchez, C; Cepila, J; Cerello, P; Cerkala, J; Chang, B; Chapeland, S; Chartier, M; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Chauvin, A; Chelnokov, V; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Cho, S; Chochula, P; Choi, K; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Colamaria, F; Colella, D; Collu, A; Colocci, M; Conesa Balbastre, G; Conesa Del Valle, Z; Connors, M E; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortés Maldonado, I; Cortese, P; Cosentino, M R; Costa, F; Crochet, P; Cruz Albino, R; Cuautle, E; Cunqueiro, L; Dahms, T; Dainese, A; Danisch, M C; Danu, A; Das, D; Das, I; Das, S; Dash, A; Dash, S; De, S; De Caro, A; de Cataldo, G; de Conti, C; de Cuveland, J; De Falco, A; De Gruttola, D; De Marco, N; De Pasquale, S; Deisting, A; Deloff, A; Dénes, E; Deplano, C; Dhankher, P; Di Bari, D; Di Mauro, A; Di Nezza, P; Diaz Corchero, M A; Dietel, T; Dillenseger, P; Divià, R; Djuvsland, Ø; Dobrin, A; Domenicis Gimenez, D; Dönigus, B; Dordic, O; Drozhzhova, T; Dubey, A K; Dubla, A; Ducroux, L; Dupieux, P; Ehlers, R J; Elia, D; Endress, E; Engel, H; Epple, E; Erazmus, B; Erdemir, I; Erhardt, F; Espagnon, B; Estienne, M; Esumi, S; Eum, J; Evans, D; Evdokimov, S; Eyyubova, G; Fabbietti, L; Fabris, D; Faivre, J; Fantoni, A; Fasel, M; Feldkamp, L; Feliciello, A; Feofilov, G; Ferencei, J; Fernández Téllez, A; Ferreiro, E G; Ferretti, A; Festanti, A; Feuillard, V J G; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Fleck, M G; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Frankenfeld, U; Fronze, G G; Fuchs, U; Furget, C; Furs, A; Fusco Girard, M; Gaardhøje, J J; Gagliardi, M; Gago, A M; Gallio, M; Gangadharan, D R; Ganoti, P; Gao, C; Garabatos, C; Garcia-Solis, E; Gargiulo, C; Gasik, P; Gauger, E F; Germain, M; Gheata, A; Gheata, M; Ghosh, P; Ghosh, S K; Gianotti, P; Giubellino, P; Giubilato, P; Gladysz-Dziadus, E; Glässel, P; Goméz Coral, D M; Gomez Ramirez, A; Gonzalez, A S; Gonzalez, V; González-Zamora, P; Gorbunov, S; Görlich, L; Gotovac, S; Grabski, V; Grachov, O A; Graczykowski, L K; Graham, K L; Grelli, A; Grigoras, A; Grigoras, C; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Gronefeld, J M; Grosse-Oetringhaus, J F; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Gulbrandsen, K; Gunji, T; Gupta, A; Gupta, R; Haake, R; Haaland, Ø; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Hamon, J C; Harris, J W; Harton, A; Hatzifotiadou, D; Hayashi, S; Heckel, S T; Hellbär, E; Helstrup, H; Herghelegiu, A; Herrera Corral, G; Hess, B A; Hetland, K F; Hillemanns, H; Hippolyte, B; Horak, D; Hosokawa, R; Hristov, P; Humanic, T J; Hussain, N; Hussain, T; Hutter, D; Hwang, D S; Ilkaev, R; Inaba, M; Incani, E

    2016-04-01

    We report the first results of elliptic (v_{2}), triangular (v_{3}), and quadrangular (v_{4}) flow of charged particles in Pb-Pb collisions at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the CERN Large Hadron Collider. The measurements are performed in the central pseudorapidity region |η|ion collisions at the highest energies. PMID:27081971

  19. Anisotropic Flow of Charged Particles in Pb-Pb Collisions at √{sN N }=5.02 TeV

    Science.gov (United States)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaraz, J. R. M.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Balasubramanian, S.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Benacek, P.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; de, S.; de Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; De Marco, N.; de Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; di Bari, D.; di Mauro, A.; di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, A. S.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosse-Oetringhaus, J. F.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Horak, D.; Hosokawa, R.; Hristov, P.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Incani, E.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.; Kim, H.; Kim, J. S.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kostarakis, P.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Lehas, F.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; León Vargas, H.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; McDonald, D.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Moreira de Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Natal da Luz, H.; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Oravec, M.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, D.; Pagano, P.; Paić, G.; Pal, S. K.; Pan, J.; Pandey, A. K.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Pereira da Costa, H.; Peresunko, D.; Pérez Lara, C. E.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Saarinen, S.; Sadhu, S.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sano, M.; Sarkar, D.; Sarkar, N.; Sarma, P.; Scapparone, E.; Scarlassara, F.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shahzad, M. I.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Sheikh, A. I.; Shigaki, K.; Shou, Q.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; de Souza, R. D.; Sozzi, F.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Stachel, J.; Stan, I.; Stankus, P.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Sumowidagdo, S.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thakur, D.; Thomas, D.; Tieulent, R.; Timmins, A. 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P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yang, H.; Yang, P.; Yano, S.; Yasin, Z.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yoon, J. H.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.; Alice Collaboration

    2016-04-01

    We report the first results of elliptic (v2), triangular (v3), and quadrangular (v4) flow of charged particles in Pb-Pb collisions at a center-of-mass energy per nucleon pair of √{sN N }=5.02 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurements are performed in the central pseudorapidity region |η |heavy-ion collisions at the highest energies.

  20. Multiple ionization and fragmentation of isolated pyrene and coronene molecules in collision with ions

    International Nuclear Information System (INIS)

    The interaction of multiply charged ions (He2+, O3+, and Xe20+) with gas-phase pericondensed polycyclic aromatic hydrocarbon (PAH) molecules of coronene (C24H12) and pyrene (C16H10) is studied for low-velocity collisions (v≤0.6 a.u.). The mass spectrometric analysis shows that singly and up to quadruply charged intact molecules are important reaction products. The relative experimental yields are compared with the results of a simple classical over-the-barrier model. For higher molecular charge states, the experimental yields decrease much more strongly than the model predictions due to the instabilities of the multiply charged PAH molecules. Even-odd oscillations with the number of carbon atoms, n, in the intensity distributions of the CnHx+ fragments indicate a linear chain structure of the fragments similar to those observed for ion-C60 collisions. The latter oscillations are known to be due to dissociation energy differences between even- and odd-n Cn-chain molecules. For PAH molecules, the average numbers of H atoms attached to the CnHx chains are larger for even-n reflecting acetylenic bond systems.