Quark contributions to baryon magnetic moments in full, quenched, and partially quenched QCD

International Nuclear Information System (INIS)

Leinweber, Derek B.

2004-01-01

The chiral nonanalytic behavior of quark-flavor contributions to the magnetic moments of octet baryons is determined in full, quenched and partially quenched QCD, using an intuitive and efficient diagrammatic formulation of quenched and partially quenched chiral perturbation theory. The technique provides a separation of quark-sector magnetic-moment contributions into direct sea-quark loop, valence-quark, indirect sea-quark loop and quenched valence contributions, the latter being the conventional view of the quenched approximation. Both meson and baryon mass violations of SU(3)-flavor symmetry are accounted for. Following a comprehensive examination of the individual quark-sector contributions to octet baryon magnetic moments, numerous opportunities to observe and test the underlying structure of baryons and the nature of chiral nonanalytic behavior in QCD and its quenched variants are discussed. In particular, the valence u-quark contribution to the proton magnetic moment provides the optimal opportunity to directly view nonanalytic behavior associated with the meson cloud of full QCD and the quenched meson cloud of quenched QCD. The u quark in Σ + provides the best opportunity to display the artifacts of the quenched approximation

Baryon Chiral Dynamics

Energy Technology Data Exchange (ETDEWEB)

Becher,

2002-08-08

After contrasting the low energy effective theory for the baryon sector with one for the Goldstone sector, I use the example of pion nucleon scattering to discuss some of the progress and open issues in baryon chiral perturbation theory.

Baryon magnetic moments in the quark model and pion cloud contributions

International Nuclear Information System (INIS)

Sato, Toshiro; Sawada, Shoji

1981-01-01

Baryon magnetic moment is studied paying attention to the effects of pion cloud which is surrounding the 'bare' baryon whose magnetic moment is given by the quark model with broken SU(6) symmetry. The precisely measured nucleon magnetic moments are reproduced by the pion cloud contributions from the distance larger than 1.4 fm. The effects of pion cloud on the hyperon magnetic moments are also discussed. It is shown that the pion cloud contributions largely reduce the discrepancies between the quark model predictions and the recent accurate experimental data on the hyperon magnetic moments. (author)

Effects of pseudoscalar-baryon channels in the dynamically generated vector-baryon resonances

Energy Technology Data Exchange (ETDEWEB)

Garzon, E.J.; Oset, E. [Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Departamento de Fisica Teorica and IFIC, Valencia (Spain)

2012-01-15

We study the interaction of vector mesons with the octet of stable baryons in the framework of the local hidden gauge formalism using a coupled-channels unitary approach, including also the pseudoscalar-baryon channels which couple to the same quantum numbers. We examine the scattering amplitudes and their poles, which can be associated to the known J{sup P}=1/2{sup -}, 3/2{sup -} baryon resonances, and determine the role of the pseudoscalar-baryon channels, changing the width and eventually the mass of the resonances generated with only the basis of vector-baryon states. (orig.)

Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances

Energy Technology Data Exchange (ETDEWEB)

Yao, De-Liang [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany); Siemens, D. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Bernard, V. [Groupe de Physique Théorique, Institut de Physique Nucléaire, UMR 8606,CNRS, University Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex (France); Epelbaum, E. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Gasparyan, A.M. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); SSC RF ITEP, Bolshaya Cheremushkinskaya 25, 117218 Moscow (Russian Federation); Gegelia, J. [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany); Tbilisi State University, 0186 Tbilisi (Georgia); Krebs, H. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Meißner, Ulf-G. [Helmholtz Institut für Strahlen- und Kernphysik andBethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany)

2016-05-05

We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S- and P-partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.

Scattering phaseshift formulas for mesons and baryons in elongated boxes

Science.gov (United States)

Lee, Frank X.; Alexandru, Andrei

2018-03-01

We derive Lüscher phaseshift formulas for two-particle states in boxes elongated in one of the dimensions. Such boxes offer a cost-effective way of varying the relative momentum of the particles. Boosted states in the elongated direction, which allow wider access to energies, are also considered. The formulas for the various scenarios (moving and zero-momentum states in cubic and elongated boxes) are compared and relations between them are clarified. The results are applicable to a wide set of meson-meson and meson-baryon elastic scattering processes, with the two-particle system having equal or unequal masses.

Baryon stopping and strangeness baryon production in a parton cascade model

International Nuclear Information System (INIS)

Nara, Yasushi

1999-01-01

A parton cascade model which is based on pQCD incorporating hard partonic scattering and dynamical hadronization scheme describes the space-time evolution of parton/hadron system produced by ultra-relativistic nuclear collisions. Hadron yield, baryon stopping and transverse momentum distribution are calculated and compared with experimental data at SPS energies. Using new version of parton cascade code VNI in which baryonic cluster formation is implemented, we calculate the net baryon number distributions and Λ yield. It is found that baryon stopping behavior at SPS energies is well accounted for within the parton cascade picture. As a consequence of the production of the baryon (u and d quark) rich parton matter, parton coalescence naturally explains the enhanced yield of Λ particle which has been observed in experiment. (author)

Scattering phases for meson and baryon resonances on general moving-frame lattices

Energy Technology Data Exchange (ETDEWEB)

Goeckeler, M. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Lage, M.; Rusetsky, A. [Bonn Univ. (Germany). Helmholtz-Inst. fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics; Meissner, U.G. [Bonn Univ. (Germany). Helmholtz-Inst. fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics; Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Forschungszentrum Juelich (Germany). Juelich Center for Hadron Physics and JARA - High Performance Computing; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zanotti, J.M. [Adelaide Univ., SA (Australia). CSSM, School of Chemistry and Physics

2012-06-15

A proposal by Luescher enables one to compute the scattering phases of elastic two-body systems from the energy levels of the lattice Hamiltonian in a finite volume. In this work we generalize the formalism to S-, P- and D-wave meson and baryon resonances, and general total momenta. Employing nonvanishing momenta has several advantages, among them making a wider range of energy levels accessible on a single lattice volume and shifting the level crossing to smaller values of m{sub {pi}}L.

Meson-baryon interactions in unitarized chiral perturbation theory

International Nuclear Information System (INIS)

Garcia Recio, G.; Nieves, J.; Ruiz Arriola, E.; Vicente Vacas, M.

2003-01-01

Meson-Baryon Interactions can be successfully described using both Chiral Symmetry and Unitarity. The s-wave meson-baryon scattering amplitude is analyzed in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry in the potential. Two body coupled channel unitarity is exactly preserved. The needed two particle irreducible matrix amplitude is taken from lowest order Chiral Perturbation Theory in a relativistic formalism. Off-shell behavior is parameterized in terms of low energy constants. The relation to the heavy baryon limit is discussed. The position of the complex poles in the second Riemann sheet of the scattering amplitude determine masses and widths baryonic resonances of the N(1535), N(1670), Λ(1405) and Λ(1670) resonances which compare well with accepted numbers

Baryon structure

International Nuclear Information System (INIS)

Morsch, H.P.; Forschungszentrum Juelich GmbH

1993-01-01

A brief review on the theoretical and experimental situation of baryon spectroscopy is first given. Then, the radial structure of baryons, related to the ground state form factors and the baryonic compressibility, is discussed. An experiment has been performed at Saturne laboratory (France) in which for the first time a compression of the nucleon is observed, exciting the P 11 (1440 MeV) resonance (Roper resonance) by α-particles. The analysis of the data indicates that this excitation covers a large fraction of the available monopole strength in the nucleon. The derived compressibility is discussed as well as the consequence for other fields, as nuclear medium effects on baryon properties, high density phenomena in nuclear collisions as well as colour transparency. In the last point the spin-flip structure of the P 11 (1440 MeV) resonance is discussed. The possibility to determine isoscalar spin-flip strength by polarized deuteron scattering is contrasted with first preliminary results from photon-induced reactions studied at Mainz which indicate a non-negligible M1 excitation of the Roper resonance. (author) 10 figs., 31 refs

Baryon stopping contribution in net-proton fluctuations measured by STAR experiment

International Nuclear Information System (INIS)

Thakur, Dhananjaya; Jakhar, Sunil; Garg, Prakhar; Sahoo, Raghunath

2016-01-01

The main goal of Beam Energy Scan program by RHIC is to scan the QCD phase diagram i.e temperature (T) versus baryon chemical potential (μB) diagram for strong interaction. At large B existence of QCD critical point (CP) and a first order phase boundary between QGP and hadronic phase is expected. The non-monotonous behavior of higher moment of the distributions of conserved quantity like net-baryon number with √s_N_N are believed to be a good signature of phase transition and CP. A non-monotonous behavior of ĸσ"2 is found around √s_N_N = 19.6 GeV by STAR experiment, which hints for the possible existence of critical point around √s_N_N=19.6 GeV. The proton distributions measured by STAR experiment have the contribution from both production as well as stopping. There may be a significant contribution of stopped protons at RHIC and lower energies which also relate to the softening of the equation of state. In the present work we have estimated the contribution of stopped protons in the protons multiplicity distributions measured by STAR experiment to calculate the higher order fluctuations

Baryon bags in strong coupling QCD

Science.gov (United States)

Gattringer, Christof

2018-04-01

We discuss lattice QCD with one flavor of staggered fermions and show that in the path integral the baryon contributions can be fully separated from quark and diquark contributions. The baryonic degrees of freedom (d.o.f.) are independent of the gauge field, and the corresponding free fermion action describes the baryons through the joint propagation of three quarks. The nonbaryonic dynamics is described by quark and diquark terms that couple to the gauge field. When evaluating the quark and diquark contributions in the strong coupling limit, the partition function completely factorizes into baryon bags and a complementary domain. Baryon bags are regions in space-time where the dynamics is described by a single free fermion made out of three quarks propagating coherently as a baryon. Outside the baryon bags, the relevant d.o.f. are monomers and dimers for quarks and diquarks. The partition sum is a sum over all baryon bag configurations, and for each bag, a free fermion determinant appears as a weight factor.

The spin predictions of the relativistic quark model for baryon decuplet production

CERN Document Server

Montvay, István

1973-01-01

Single-quark scattering contributions are considered in the case of ground-state decuplet baryon production. It is shown within the framework of an explicitly covariant approach that the spin consequences of the quark additivity assumption hold in the t-channel helicity frame independently of much of the details of the model. (12 refs).

The exchange of correlated pions and kaons in the baryon-baryon interaction

International Nuclear Information System (INIS)

Reuber, A.G.

1995-09-01

The exchange of two correlated pions or kaons provides the main part of the intermediate-range attraction between two baryons. In this work, a dynamical model for correlated two-pion and two-kaon exchange in the baryon-baryon interaction is presented, both in the scalar-isoscalar (σ) and the vector-isovector (ρ) channel. The contribution of correlated ππ and K anti K exchange is derived from the amplitudes for the transition of a baryon-antibaryon state (B anti B') to a ππ or K anti K state in the pseudophysical region by applying dispersion theory and unitarity. For the B anti B'→ππ, K anti K amplitudes a microscopic model is constructed, which is based on the hadron-exchange picture. The Born terms include contributions from baryon-exchange as well as ρ-pole diagrams. The correlations between the two pseudoscalar mesons are taken into account exactly by means of ππ-K anti K amplitudes derived likewise from a meson-exchange model, which is in line with the empirical ππ data. The parameters of the B anti B'→ππ, K anti K model, which are related to each other by the assumption of SU(3) symmetry, are determined by the adjustment to the quasiempirical N anti N→ππ amplitudes in the pseudophysical region. It is found that correlated K anti K exchange being negligible in the NN interaction plays an important role in the σ-channel for baryon-baryon states with non-vanishing strangeness. The strength of correlated ππ plus K anti K exchange in the σ-channel decreases with the strangeness of the baryon-baryon system becoming more negative. Due to the admixture of baryon-exchange processes to the SU(3)-symmetric ρ-pole contributions the results for correlated ππ-exchange in the vector-isovector channel deviate from what is expected in the naive SU(3) picture for genuine ρ-exchange. (orig.)

Scattering amplitudes to all orders in meson exchange

International Nuclear Information System (INIS)

Silbar, R.R.; Mattis, M.P.

1990-01-01

As the number of colors in QCD, N C , becomes large, it is possible to sum up all meson-exchange contributions, however arbitrarily complicated, to meson-baryon and baryon-baryon scattering. A semi-classical structure for the two-flavor theory emerges, in close correspondence to vector-meson-augmented Skyrme models. In this limit, baryons act as extended static sources for the classical meson fields. This leads to non-linear differential equations for the classical meson fields which can be solved numerically for static radial (hedgehog-like) solutions. The non-linear terms in the equations of motion for the quantized meson fields can then be simplified, to leading order in 1/N C , by replacing all factors of the meson field but one by the previously-found classical field. This results in linear, Schroedinger-like equations, which are easily solved. For the meson-baryon case the solution can be subsequently analyzed to obtain the phase shifts for the scattering and, from these, the baryon resonance spectrum of the model. As the warm-up, we have carried out this calculation for the simple case of σ mesons only, finding sensible results. 8 refs., 3 figs

Chiral soliton models for baryons

International Nuclear Information System (INIS)

Weigel, H.

2008-01-01

This concise research monograph introduces and reviews the concept of chiral soliton models for baryons. In these models, baryons emerge as (topological) defects of the chiral field. The many applications shed light on a number of baryon properties, ranging from static properties via nucleon resonances and deep inelastic scattering to even heavy ion collisions. As far as possible, the theoretical investigations are confronted with experiment. Conceived to bridge the gap between advanced graduate textbooks and the research literature, this volume also features a number of appendices to help nonspecialist readers to follow in more detail some of the calculations in the main text. (orig.)

Baryon destruction by asymmetric dark matter

International Nuclear Information System (INIS)

Davoudiasl, Hooman; Morrissey, David E.; Tulin, Sean; Sigurdson, Kris

2011-01-01

We investigate new and unusual signals that arise in theories where dark matter is asymmetric and carries a net antibaryon number, as may occur when the dark matter abundance is linked to the baryon abundance. Antibaryonic dark matter can cause induced nucleon decay by annihilating visible baryons through inelastic scattering. These processes lead to an effective nucleon lifetime of 10 29 -10 32 yrs in terrestrial nucleon decay experiments, if baryon number transfer between visible and dark sectors arises through new physics at the weak scale. The possibility of induced nucleon decay motivates a novel approach for direct detection of cosmic dark matter in nucleon decay experiments. Monojet searches (and related signatures) at hadron colliders also provide a complementary probe of weak-scale dark-matter-induced baryon number violation. Finally, we discuss the effects of baryon-destroying dark matter on stellar systems and show that it can be consistent with existing observations.

Production of baryons with large transverse momentum

International Nuclear Information System (INIS)

Landshoff, P.V.; Polkinghorne, J.C.; Scott, D.M.

1975-01-01

The multiple scattering of constituent quarks provides a natural mechanism for fairly copious production of large-transverse-momentum baryons in nucleon--nucleon collisions. The predicted scaling law agrees well with available data, and the mechanism provides a qualitative explanation of nuclear-target effects. In comparison with previous parton models, correlations are predicted to be qualitatively different, and large-p/sub T/ baryon production by meson beams is relatively suppressed

Unified Origin for Baryonic Visible Matter and Antibaryonic Dark Matter

International Nuclear Information System (INIS)

Davoudiasl, Hooman; Morrissey, David E.; Tulin, Sean; Sigurdson, Kris

2010-01-01

We present a novel mechanism for generating both the baryon and dark matter densities of the Universe. A new Dirac fermion X carrying a conserved baryon number charge couples to the standard model quarks as well as a GeV-scale hidden sector. CP-violating decays of X, produced nonthermally in low-temperature reheating, sequester antibaryon number in the hidden sector, thereby leaving a baryon excess in the visible sector. The antibaryonic hidden states are stable dark matter. A spectacular signature of this mechanism is the baryon-destroying inelastic scattering of dark matter that can annihilate baryons at appreciable rates relevant for nucleon decay searches.

Unified origin for baryonic visible matter and antibaryonic dark matter.

Science.gov (United States)

Davoudiasl, Hooman; Morrissey, David E; Sigurdson, Kris; Tulin, Sean

2010-11-19

We present a novel mechanism for generating both the baryon and dark matter densities of the Universe. A new Dirac fermion X carrying a conserved baryon number charge couples to the standard model quarks as well as a GeV-scale hidden sector. CP-violating decays of X, produced nonthermally in low-temperature reheating, sequester antibaryon number in the hidden sector, thereby leaving a baryon excess in the visible sector. The antibaryonic hidden states are stable dark matter. A spectacular signature of this mechanism is the baryon-destroying inelastic scattering of dark matter that can annihilate baryons at appreciable rates relevant for nucleon decay searches.

Multistrange Meson-Baryon Dynamics and Resonance Generation

Science.gov (United States)

Khemchandani, K. P.; Martínez Torres, A.; Hosaka, A.; Nagahiro, H.; Navarra, F. S.; Nielsen, M.

2018-05-01

In this talk I review our recent studies on meson-baryon systems with strangeness - 1 and - 2. The motivation of our works is to find resonances generated as a consequence of coupled channel meson-baryon interactions. The coupled channels are all meson-baryon systems formed by combining a pseudoscalar or a vector meson with an octet baryon such that the system has the strange quantum number equal to - 1 or - 2. The lowest order meson-baryon interaction amplitudes are obtained from Lagrangians based on the chiral and the hidden local symmetries related to the vector mesons working as the gauge bosons. These lowest order amplitudes are used as an input to solve the Bethe-Salpeter equation and a search for poles is made in the resulting amplitudes, in the complex plane. In case of systems with strangeness - 1, we find evidence for the existence of some hyperons such as: Λ(2000), Σ(1750), Σ(1940), Σ(2000). More recently, in the study of strangeness - 2 systems we have found two narrow resonances which can be related to Ξ (1690) and Ξ(2120). In this latter work, we have obtained the lowest order amplitudes relativistically as well as in the nonrelativistic approximation to solve the scattering equations. We find that the existence of the poles in the complex plane does not get affected by the computation of the scattering equation with the lowest order amplitudes obtained in the nonrelativistic approximation.

The relative impact of baryons and cluster shape on weak lensing mass estimates of galaxy clusters

Science.gov (United States)

Lee, B. E.; Le Brun, A. M. C.; Haq, M. E.; Deering, N. J.; King, L. J.; Applegate, D.; McCarthy, I. G.

2018-05-01

Weak gravitational lensing depends on the integrated mass along the line of sight. Baryons contribute to the mass distribution of galaxy clusters and the resulting mass estimates from lensing analysis. We use the cosmo-OWLS suite of hydrodynamic simulations to investigate the impact of baryonic processes on the bias and scatter of weak lensing mass estimates of clusters. These estimates are obtained by fitting NFW profiles to mock data using MCMC techniques. In particular, we examine the difference in estimates between dark matter-only runs and those including various prescriptions for baryonic physics. We find no significant difference in the mass bias when baryonic physics is included, though the overall mass estimates are suppressed when feedback from AGN is included. For lowest-mass systems for which a reliable mass can be obtained (M200 ≈ 2 × 1014M⊙), we find a bias of ≈-10 per cent. The magnitude of the bias tends to decrease for higher mass clusters, consistent with no bias for the most massive clusters which have masses comparable to those found in the CLASH and HFF samples. For the lowest mass clusters, the mass bias is particularly sensitive to the fit radii and the limits placed on the concentration prior, rendering reliable mass estimates difficult. The scatter in mass estimates between the dark matter-only and the various baryonic runs is less than between different projections of individual clusters, highlighting the importance of triaxiality.

Isospin breaking in pion-nucleon scattering at threshold by radiative processes

CERN Document Server

Ericson, Torleif Eric Oskar

2006-01-01

We investigate the dispersive contribution by radiative processes such as (pi- proton to neutron gamma) and (pi- proton to Delta gamma) to the pion-nucleon scattering lengths of charged pions in the heavy baryon limit. They give a large isospin violating contribution in the corresponding isoscalar scattering length, but only a small violation in the isovector one. These terms contribute 6.3(3)% to the 1s level shift of pionic hydrogen and give a chiral constant F_pi^2f_1=-25.8(8) MeV.

Quark color-hyperfine interactions in baryons

International Nuclear Information System (INIS)

Anselmino, M.; Lichtenberg, D.B.

1990-01-01

We consider the contribution from the color-hyperfine interaction to the energies of groundstate hadrons, with an emphasis on baryons. We use experimental information about how the color-hyperfine term depends on flavor to make predictions about the masses of baryons containing a heavy quark. We then generalize some relations between color-hyperfine matrix elements in mesons and baryons to obtain a number of additional predictions about the masses of as-yet unobserved baryons. Most of our predictions are in the form of inequalities. (orig.)

Magnetic monopoles and baryon decay

International Nuclear Information System (INIS)

Pak, N.; Panagiotakopoulos, C.; Shafi, Q.

1982-08-01

The scattering of a non-relativistic quark from a GUT monopole is affected by the anomalous magnetic moment of the quark. In order that monopole catalysis of baryon decay can occur, it must be assumed that the anomalous magnetic moment decreases sufficiently rapidly below the QCD scale. (author)

The baryonic Tully-Fisher relationship for S{sup 4}G galaxies and the 'condensed' baryon fraction of galaxies

Energy Technology Data Exchange (ETDEWEB)

Zaritsky, Dennis [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Courtois, Helene; Sorce, Jenny [Université Lyon 1, CNRS/IN2P3, Institut de Physique Nucléaire, Lyon (France); Muñoz-Mateos, Juan-Carlos; Kim, T.; Mizusawa, T.; Sheth, K. [National Radio Astronomy Observatory/NAASC, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Erroz-Ferrer, S. [Instituto de Astrofísica de Canarias, Vía Láctea s/n 38205 La Laguna (Spain); Comerón, S.; Laurikainen, E.; Laine, J.; Salo, H. [Astronomy Division, Department of Physical Sciences, University of Oulu, P.O. Box 3000, FI-90014, Oulu (Finland); Gadotti, D. A. [European Southern Observatory, Casilla 19001, Santiago 19 (Chile); Gil de Paz, A. [Departamento de Astrofísica, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Hinz, J. L. [MMTO, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Menéndez-Delmestre, K. [Universidade Federal do Rio de Janeiro, Observatório do Valongo, Ladeira Pedro Antônio, 43, CEP 20080-090, Rio de Janeiro (Brazil); Regan, M. W. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Seibert, M. [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Athanassoula, E.; Bosma, A., E-mail: dennis.zaritsky@gmail.com [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France); and others

2014-06-01

We combine data from the Spitzer Survey for Stellar Structure in Galaxies, a recently calibrated empirical stellar mass estimator from Eskew et al., and an extensive database of H I spectral line profiles to examine the baryonic Tully-Fisher (BTF) relation. We find (1) that the BTF has lower scatter than the classic Tully-Fisher (TF) relation and is better described as a linear relationship, confirming similar previous results, (2) that the inclusion of a radial scale in the BTF decreases the scatter but only modestly, as seen previously for the TF relation, and (3) that the slope of the BTF, which we find to be 3.5 ± 0.2 (Δlog M {sub baryon}/Δlog v{sub c} ), implies that on average a nearly constant fraction (∼0.4) of all baryons expected to be in a halo are 'condensed' onto the central region of rotationally supported galaxies. The condensed baryon fraction, M {sub baryon}/M {sub total}, is, to our measurement precision, nearly independent of galaxy circular velocity (our sample spans circular velocities, v {sub c} , between 60 and 250 km s{sup –1}, but is extended to v{sub c} ∼ 10 km s{sup –1} using data from the literature). The observed galaxy-to-galaxy scatter in this fraction is generally ≤ a factor of 2 despite fairly liberal selection criteria. These results imply that cooling and heating processes, such as cold versus hot accretion, mass loss due to stellar winds, and active galactic nucleus driven feedback, to the degree that they affect the global galactic properties involved in the BTF, are independent of halo mass for galaxies with 10 < v{sub c} < 250 km s{sup –1} and typically introduce no more than a factor of two range in the resulting M {sub baryon}/M {sub total}. Recent simulations by Aumer et al. of a small sample of disk galaxies are in excellent agreement with our data, suggesting that current simulations are capable of reproducing the global properties of individual disk galaxies. More detailed comparison to models

Electromagnetic corrections to baryon masses

International Nuclear Information System (INIS)

Durand, Loyal; Ha, Phuoc

2005-01-01

We analyze the electromagnetic contributions to the octet and decuplet baryon masses using the heavy-baryon approximation in chiral effective field theory and methods we developed in earlier analyses of the baryon masses and magnetic moments. Our methods connect simply to Morpurgo's general parametrization of the electromagnetic contributions and to semirelativistic quark models. Our calculations are carried out including the one-loop mesonic corrections to the basic electromagnetic interactions, so to two loops overall. We find that to this order in the chiral loop expansion there are no three-body contributions. The Coleman-Glashow relation and other sum rules derived in quark models with only two-body terms therefore continue to hold, and violations involve at least three-loop processes and can be expected to be quite small. We present the complete formal results and some estimates of the matrix elements here. Numerical calculations will be presented separately

Search for narrow baryons in pi /sup -/p elastic scattering at large angles

CERN Document Server

Baillon, Paul; Benayoun, M; Chauveau, J; Chew, D; Ferro-Luzzi, M; Kahane, J; Lellouch, D; Leruste, P; Liaud, P; Moreau, F; Perreau, J M; Séguinot, Jacques; Sené, R; Tocqueville, J; Urban, M

1980-01-01

Hoping to find resonant structures in the momentum dependence of pi /sup -/p elastic scattering the authors have measured the differential cross section for this reaction at c.m. angles near 90 degrees . An intense pion beam ( approximately=10/sup 7/ pi /s) has been used, together with a high incident momentum resolution (dP/P approximately =2*10/sup -4/), to scan the region of laboratory momenta from 5.75 to 13.02 GeV/c (c.m. energy from 3.42 to 5.03 GeV). The sensitivity attained by the experiment is such that signals would have been seen corresponding to the formation of non-strange baryon resonances having width larger than approximately=0.1 MeV and elasticity larger than a few per cent. Within these limits no resonances were sighted. (4 refs) .

Self-Energy of Decuplet Baryons in Nuclear Matter

OpenAIRE

Ouellette, Stephen M.; Seki, Ryoichi

1997-01-01

We calculate, in chiral perturbation theory, the change in the self-energy of decuplet baryons in nuclear matter. These self-energy shifts are relevant in studies of meson-nucleus scattering and of neutron stars. Our results are leading order in an expansion in powers of the ratio of characteristic momenta to the chiral symmetry-breaking scale (or the nucleon mass). Included are contact diagrams generated by 4-baryon operators, which were neglected in earlier studies for the $\\Delta$ isomulti...

Novel baryon resonances in the Skyrme model

International Nuclear Information System (INIS)

Hussain, F.; Sri Ram, M.S.

1985-01-01

We predict a novel family of baryons with or without the charm quantum number by quantizing the ''maximal solitons'' in the SU(4) Skyrme model. The baryon number B of these solitons can take any integer value. The low-lying states with B = 1 belong to 4( with spin (3/2), 20( with spin (1/2), (3/2), (5/2), or (7/2), and 20('' with spin (3/2), (5/2), or (9/2). The charm-zero states among them could correspond to some of the observed resonances in meson-baryon scattering between 1.5--2 GeV. The lowest among the dibaryon states is an SU(3) singlet contained in the 10( of SU(4) with spin 1, with mass in the range 2.5--3 GeV

Baryonic forces and hyperons in nuclear matter from SU(3) chiral effective field theory

Energy Technology Data Exchange (ETDEWEB)

Petschauer, Stefan Karl

2016-02-12

In this work the baryon-baryon interaction is studied at next-to-leading order in SU(3) chiral effective field theory and applied to hyperon-nucleon scattering. The properties of hyperons in isospin-symmetric as well as asymmetric nuclear matter are calculated within the Bruecker-Hartree-Fock formalism. Moreover, the leading three-baryon interaction is derived and its low-energy constants are estimated from decuplet intermediate states. We conclude, that chiral effective field theory is a well-suited tool to describe the baryonic forces.

Regge analysis of diffractive and leading baryon structure functions from deep inelastic scattering

International Nuclear Information System (INIS)

Batista, M.; Covolan, R.J.M.; Montanha, J.

2002-01-01

In this paper we present a combined analysis of the H1 data on leading baryon and diffractive structure functions from DIS, which are handled as two components of the same semi-inclusive process. The available structure function data are analyzed in a series of fits in which three main exchanges are taken into account: the Pomeron, Reggeon, and pion. For each of these contributions, Regge factorization of the correspondent structure function is assumed. By this procedure, we extract information about the interface between the diffractive, Pomeron-dominated, region and the leading proton spectrum, which is mostly ruled by secondary exchanges. One of the main results is that the relative Reggeon contribution to the semi-inclusive structure function is much smaller than the one obtained from an analysis of the diffractive structure function alone

Heavy quark symmetry at large recoil: The case of baryons

International Nuclear Information System (INIS)

Koerner, J.G.; Kroll, P.

1992-02-01

We analyze the large recoil behaviour of heavy baryon transition form factors in semi-leptonic decays. We use a generalized Brodsky-Lepage hard scattering formalism where diquarks are considered as quasi-elementary constituents of baryons. In the limit of infinitely heavy quark masses the large recoil form factors exhibit a new model-independent heavy quark symmetry which is reminiscent but not identical to the Isgur-Wise symmetry at low recoil. (orig.)

Neutrino physics with dark matter experiments and the signature of new baryonic neutral currents

International Nuclear Information System (INIS)

Pospelov, Maxim

2011-01-01

New neutrino states ν b , sterile under the standard model interactions, can be coupled to baryons via the isoscalar vector currents that are much stronger than the standard model weak interactions. If some fraction of solar neutrinos oscillate into ν b on their way to Earth, the coherently enhanced elastic ν b -nucleus scattering can generate a strong signal in the dark matter detectors. For the interaction strength a few hundred times stronger than the weak force, the elastic ν b -nucleus scattering via new baryonic currents may account for the existing anomalies in the direct detection dark matter experiments at low recoil. We point out that for solar-neutrino energies, the baryon-current-induced inelastic scattering is suppressed, so that the possible enhancement of a new force is not in conflict with signals at dedicated neutrino detectors. We check this explicitly by calculating the ν b -induced deuteron breakup, and the excitation of a 4.4 MeV γ line in 12 C. A stronger-than-weak force coupled to the baryonic current implies the existence of a new Abelian gauge group U(1) B with a relatively light gauge boson.

Odd-parity light baryon resonances

International Nuclear Information System (INIS)

Gamermann, D.; Garcia-Recio, C.; Salcedo, L. L.; Nieves, J.

2011-01-01

We use a consistent SU(6) extension of the meson-baryon chiral Lagrangian within a coupled channel unitary approach in order to calculate the T matrix for meson-baryon scattering in the s wave. The building blocks of the scheme are the π and N octets, the ρ nonet and the Δ decuplet. We identify poles in this unitary T matrix and interpret them as resonances. We study here the nonexotic sectors with strangeness S=0, -1, -2, -3 and spin J=(1/2), (3/2) and (5/2). Many of the poles generated can be associated with known N, Δ, Σ, Λ, Ξ and Ω resonances with negative parity. We show that most of the low-lying three and four star odd-parity baryon resonances with spin (1/2) and (3/2) can be related to multiplets of the spin-flavor symmetry group SU(6). This study allows us to predict the spin-parity of the Ξ(1620), Ξ(1690), Ξ(1950), Ξ(2250), Ω(2250) and Ω(2380) resonances, which have not been determined experimentally yet.

Strange sea quark effects for low lying baryons

International Nuclear Information System (INIS)

Upadhyay, A.; Batra, Meenakshi

2013-01-01

Assuming hadrons as an ensemble of quark-gluon Fock states, contributions from sea quarks and gluons can be studied in detail for ground state baryons. Spin crisis of nucleons say that only a small fraction of proton spin is carried by valence quarks. Rest part is distributed among gluons and sea which includes both strange and non-strange quark-anti-quark pairs. This necessitates the study of strange sea quark contribution for other baryons too due to higher mass and presence of strange quark in valence part. Recent studies have also studied strange sea contribution for baryons using different models. We implement the statistical modeling techniques to compute strange sea quark content for baryon octet. Statistical model has already been applied to study sea quark content for nucleons in the form of scalar, vector and tensor sea. In our present work the same idea has been extended for strange sea to probe the structure in more detail. (author)

Properties of light flavour baryons in hypercentral quark model

Indian Academy of Sciences (India)

Light baryons; magnetic moments; transition magnetic moment; radiative decay width. ... particles are produced by scattering the pion, photon, or electron ... and decuplet) for testing any model hypothesis and understanding the dynamics of ...

Are baryonic galactic halos possible

International Nuclear Information System (INIS)

Olive, K.A.; Hegyi, D.J.

1986-01-01

There is little doubt from the rotation curves of spiral galaxies that galactic halos must contain large amounts of dark matter. In this contribution, the authors review arguments which indicate that it is very unlikely that galactic halos contain substantial amounts of baryonic matter. While the authors would like to be able to present a single argument which would rule out baryonic matter, at the present time they are only able to present a collection of arguments each of which argues against one form of baryonic matter. These include: 1) snowballs; 2) gas; 3) low mass stars and Jupiters; 4) high mass stars; and 5) high metalicity objects such as rooks or dust. Black holes, which do not have a well defined baryon number, are also a possible candidate for halo matter. They briefly discuss black holes

Density-dependent effective baryon–baryon interaction from chiral three-baryon forces

Energy Technology Data Exchange (ETDEWEB)

Petschauer, Stefan, E-mail: stefan.petschauer@ph.tum.de [Physik Department, Technische Universität München, D-85747 Garching (Germany); Haidenbauer, Johann [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Kaiser, Norbert [Physik Department, Technische Universität München, D-85747 Garching (Germany); Meißner, Ulf-G. [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, D-53115 Bonn (Germany); Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Weise, Wolfram [Physik Department, Technische Universität München, D-85747 Garching (Germany)

2017-01-15

A density-dependent effective potential for the baryon–baryon interaction in the presence of the (hyper)nuclear medium is constructed, based on the leading (irreducible) three-baryon forces derived within SU(3) chiral effective field theory. We evaluate the contributions from three classes: contact terms, one-pion exchange and two-pion exchange. In the strangeness-zero sector we recover the known result for the in-medium nucleon–nucleon interaction. Explicit expressions for the ΛN in-medium potential in (asymmetric) nuclear matter are presented. Our results are suitable for implementation into calculations of (hyper)nuclear matter. In order to estimate the low-energy constants of the leading three-baryon forces we introduce the decuplet baryons as explicit degrees of freedom and construct the relevant terms in the minimal non-relativistic Lagrangian. With these, the constants are estimated through decuplet saturation. Utilizing this approximation we provide numerical results for the effect of the three-body force in symmetric nuclear matter and pure neutron matter on the ΛN interaction. A moderate repulsion that increases with density is found in comparison to the free ΛN interaction.

A possible description of baryon dynamics in dual and gauge theories

CERN Document Server

Rossi, G C

1977-01-01

The authors generalize to baryons a framework recently proposed in order to unify gauge, dual and Regge-Gribov theories of mesons. They depart from the 1/N/sub colour/ expansion of quantum chromodynamics (QCD) and replace it by a more general definition of a 'dual' approximation of QCD, based on the zero-width limit. Theoretical and phenomenological consequences of the scheme are derived. For N/sub colour/=3, the baryon resembles a Y shaped string; three families of new 'baryonium' bound states are predicted and rough estimates of intercepts and slopes of the associated Regge trajectories are given. A new type of Zweig-like selection rule is found to hold in leading order and its violations through higher-order topologies are discussed. Duality diagrams for baryons are ambiguous unless implemented with extra lines indicating the flow of certain colour indices. Duality between scattering and annihilation channels is found in BB scattering and its consequences are discussed. Some justification is given for the ...

Lattice QCD studies on baryon interactions in the strangeness -2 sector with physical quark masses

Science.gov (United States)

Sasaki, Kenji; Aoki, Sinya; Doi, Takumi; Gongyo, Shinya; Hatsuda, Tetsuo; Ikeda, Yoichi; Inoue, Takashi; Iritani, Takumi; Ishii, Noriyoshi; Miyamoto, Takaya

2018-03-01

We investigate baryon-baryon (BB) interactions in the strangeness S = -2 sector via the coupled-channel HAL QCD method which enables us to extract the scattering observables from Nambu-Bethe-Salpeter (NBS) wave function on the lattice. The simulations are performed with (almost) physical quark masses (mπ = 146MeV) and a huge lattice volume of La = 8.1fm. We discuss the fate of H-dibaryon state through the ΛΛ and NΞ coupled-channel scatterings

Learning from the scatter in type ia supernovae

Energy Technology Data Exchange (ETDEWEB)

Dodelson, Scott; /Fermilab /Chicago U., Astron. Astrophys. Ctr.; Vallinotto, Alberto; /Fermilab /Chicago U.

2005-11-01

Type Ia Supernovae are standard candles so their mean apparent magnitude has been exploited to learn about the redshift-distance relationship. Besides intrinsic scatter in this standard candle, additional scatter is caused by gravitational magnification by large scale structure. Here they probe the dependence of this dispersion on cosmological parameters and show that information about the amplitude of clustering, {sigma}{sub s}, is contained in the scatter. In principle, it will be possible to constrain {sigma}{sub s} to within 5% with observations of 2000 Type Ia Supernovae. They identify three sources of systematic error--evolution of intrinsic scatter, baryon contributions to lensing, and non-Gaussianity of lensing--which will make this measurement difficult.

Baryon asymmetry, dark matter and local baryon number

International Nuclear Information System (INIS)

Fileviez Pérez, Pavel; Patel, Hiren H.

2014-01-01

We propose a new mechanism to understand the relation between baryon and dark matter asymmetries in the universe in theories where the baryon number is a local symmetry. In these scenarios the B−L asymmetry generated through a mechanism such as leptogenesis is transferred to the dark matter and baryonic sectors through sphalerons processes which conserve total baryon number. We show that it is possible to have a consistent relation between the dark matter relic density and the baryon asymmetry in the universe even if the baryon number is broken at the low scale through the Higgs mechanism. We also discuss the case where one uses the Stueckelberg mechanism to understand the conservation of baryon number in nature.

Baryonic and Non-Baryonic Dark Matter

OpenAIRE

Carr, Bernard

2000-01-01

Cosmological nucleosynthesis calculations imply that there should be both non-baryonic and baryonic dark matter. Recent data suggest that some of the non-baryonic dark matter must be "hot" (i.e. massive neutrinos) and there may also be evidence for "cold" dark matter (i.e. WIMPs). If the baryonic dark matter resides in galactic halos, it is likely to be in the form of compact objects (i.e. MACHOs) and these would probably be the remnants of a first generation of pregalactic or protogalactic P...

Lattice QCD studies on baryon interactions in the strangeness -2 sector with physical quark masses

Directory of Open Access Journals (Sweden)

Sasaki Kenji

2018-01-01

Full Text Available We investigate baryon-baryon (BB interactions in the strangeness S = −2 sector via the coupled-channel HAL QCD method which enables us to extract the scattering observables from Nambu-Bethe-Salpeter (NBS wave function on the lattice. The simulations are performed with (almost physical quark masses (mπ = 146MeV and a huge lattice volume of La = 8.1fm. We discuss the fate of H-dibaryon state through the ΛΛ and NΞ coupled-channel scatterings

Analysis of dynamical corrections to baryon magnetic moments

International Nuclear Information System (INIS)

Ha, Phuoc; Durand, Loyal

2003-01-01

We present and analyze QCD corrections to the baryon magnetic moments in terms of the one-, two-, and three-body operators which appear in the effective field theory developed in our recent papers. The main corrections are extended Thomas-type corrections associated with the confining interactions in the baryon. We investigate the contributions of low-lying angular excitations to the baryon magnetic moments quantitatively and show that they are completely negligible. When the QCD corrections are combined with the nonquark model contributions of the meson loops, we obtain a model which describes the baryon magnetic moments within a mean deviation of 0.04 μ N . The nontrivial interplay of the two types of corrections to the quark-model magnetic moments is analyzed in detail, and explains why the quark model is so successful. In the course of these calculations, we parametrize the general spin structure of the j=(1/2) + baryon wave functions in a form which clearly displays the symmetry properties and the internal angular momentum content of the wave functions, and allows us to use spin-trace methods to calculate the many spin matrix elements which appear in the expressions for the baryon magnetic moments. This representation may be useful elsewhere

Meson-baryon-baryon vertex function and the Ward-Takahashi identity

International Nuclear Information System (INIS)

Wang, S.; Banerjee, M.K.

1996-01-01

Ohta proposed a solution for the well-known difficulty of satisfying the Ward-Takahashi identity for a photo-meson-baryon-baryon amplitude (γMBB) when a dressed meson-baryon-baryon (MBB) vertex function is present. He obtained a form for the γMBB amplitude which contained, in addition to the usual pole terms, longitudinal seagull terms which were determined entirely by the MBB vertex function. He arrived at his result by using a Lagrangian which yields the MBB vertex function at tree level. We show that such a Lagrangian can be neither Hermitian nor charge conjugation invariant. We have been able to reproduce Ohta close-quote s result for the γMBB amplitude using the Ward-Takahashi identity and no other assumption, dynamical or otherwise, and the most general form for the MBB and γMBB vertices. However, contrary to Ohta close-quote s finding, we find that the seagull terms are not robust. The seagull terms extracted from the γMBB vertex occur unchanged in tree graphs, such as in an exchange current amplitude. But the seagull terms which appear in a loop graph, as in the calculation of an electromagnetic form factor, are, in general, different. The whole procedure says nothing about the transverse part of the (γMBB) vertex and its contributions to the amplitudes in question. copyright 1996 The American Physical Society

Holographic black hole engineering at finite baryon chemical potential

International Nuclear Information System (INIS)

Rougemont, Romulo

2017-01-01

This is a contribution for the Proceedings of the Conference Hot Quarks 2016, held at South Padre Island, Texas, USA, 12-17 September 2016. I briefly review some thermodynamic and baryon transport results obtained from a bottom-up Einstein-Maxwell-Dilaton holographic model engineered to describe the physics of the quark-gluon plasma at finite temperature and baryon density. The results for the equation of state, baryon susceptibilities, and the curvature of the crossover band are in quantitative agreement with the corresponding lattice QCD results with 2 + 1 flavors and physical quark masses. Baryon diffusion is predicted to be suppressed by increasing the baryon chemical potential. (paper)

On Productions of Net-Baryons in Central Au-Au Collisions at RHIC Energies

Directory of Open Access Journals (Sweden)

Ya-Hui Chen

2015-01-01

Full Text Available The transverse momentum and rapidity distributions of net-baryons (baryons minus antibaryons produced in central gold-gold (Au-Au collisions at 62.4 and 200 GeV are analyzed in the framework of a multisource thermal model. Each source in the model is described by the Tsallis statistics to extract the effective temperature and entropy index from the transverse momentum distribution. The two parameters are used as input to describe the rapidity distribution and to extract the rapidity shift and contribution ratio. Then, the four types of parameters are used to structure some scatter plots of the considered particles in some three-dimensional (3D spaces at the stage of kinetic freeze-out, which are expected to show different characteristics for different particles and processes. The related methodology can be used in the analyses of particle production and event holography, which are useful for us to better understand the interacting mechanisms.

Heavy baryons

International Nuclear Information System (INIS)

Koerner, J.G.

1994-06-01

We review the experimental and theoretical status of baryons containing one heavy quark. The charm and bottom baryon states are classified and their mass spectra are listed. The appropriate theoretical framework for the description of heavy baryons is the Heavy Quark Effective Theory, whose general ideas and methods are introduced and illustrated in specific examples. We present simple covariant expressions for the spin wave functions of heavy baryons including p-wave baryons. The covariant spin wave functions are used to determine the Heavy Quark Symmetry structure of flavour-changing current-induced transitions between heavy baryons as well as one-pion and one-photon transitions between heavy baryons of the same flavour. We discuss 1/m Q corrections to the current-induced transitions as well as the structure of heavy to light baryon transitions. Whenever possible we attempt to present numbers to compare with experiment by making use of further model-dependent assumptions as e.g. the constituent picture for light quarks. We highlight recent advances in the theoretical understanding of the inclusive decays of hadrons containing one heavy quark including polarization. For exclusive semileptonic decays we discuss rates, angular decay distributions and polarization effects. We provide an update of the experimental and theoretical status of lifetimes of heavy baryons and of exclusive nonleptonic two body decays of charm baryons. (orig.)

Baryons and baryon resonances in nuclear matter

Science.gov (United States)

Lenske, Horst; Dhar, Madhumita; Gaitanos, Theodoros; Cao, Xu

2018-01-01

Theoretical approaches to the production of hyperons and baryon resonances in elementary hadronic reactions and heavy ion collisions are reviewed. The focus is on the production and interactions of baryons in the lowest SU(3) flavor octet and states from the next higher SU(3) flavor decuplet. Approaches using the SU(3) formalism for interactions of mesons and baryons and effective field theory for hyperons are discussed. An overview of application to free space and in-medium baryon-baryon interactions is given and the relation to a density functional theory is indicated. The intimate connection between baryon resonances and strangeness production is shown first for reactions on the nucleon. Pion-induced hypernuclear reactions are shown to proceed essentially through the excitation of intermediate nucleon resonances. Transport theory in conjunction with a statistical fragmentation model is an appropriate description of hypernuclear production in antiproton and heavy ion induced fragmentation reactions. The excitation of subnuclear degrees of freedom in peripheral heavy ion collisions at relativistic energies is reviewed. The status of in-medium resonance physics is discussed.

Baryon-baryon mixing in hypernuclei

International Nuclear Information System (INIS)

Gibson, B.F.

1998-01-01

Implications of few-body hypernuclei for the understanding of the baryon-baryon interaction are examined. Octet-octet coupling effects not present in conventional, non strange nuclei are the focus. The need to identify strangeness -2 hypernuclei to test model predictions is emphasized

Charming baryons

International Nuclear Information System (INIS)

Garcia-Recio, C.; Salcedo, L.L.; Gamermann, D.; Nieves, J.; Romanets, O.; Tolos, L.

2014-01-01

We study odd-parity baryonic resonances with one heavy and three light flavors, dynamically generated by meson-baryon interactions. Special attention is paid to Heavy Quark Spin Symmetry (HQSS), hence pseudoscalar and vector mesons and baryons with J π = 1/2 + and 3/2 + are considered as constituent hadrons. For the hidden-charm sector (N c = N c ¯ = 1), the meson-baryon Lagrangian with Heavy Flavor Symmetry is constructed by a minimal extension of the SU(3) Weinberg-Tomozawa (WT) Lagrangian to fulfill HQSS, such that not new parameters are needed. This interaction can be presented in different formal ways: as a Field Lagrangian, as Hadron creation-annihilation operators, as SU(6)×HQSS group projectors and as multichannel matrices. The multichannel Bethe-Salpeter equation is solved for odd-parity light baryons, hidden-charm N and Δ and Beauty Baryons (Λ b ). Results of calculations with this model are shown in comparison with other models and experimental values for baryonic resonances. (author)

Extraction of the pion-nucleon sigma-term from the spectrum of exotic baryons

International Nuclear Information System (INIS)

Schweitzer, P.

2004-01-01

The pion-nucleon sigma-term is extracted on the basis of the soliton picture of the nucleon from the mass spectrum of usual and the recently observed exotic baryons, assuming that they have positive parity. The value found is consistent with that inferred by means of conventional methods from pion-nucleon scattering data. The study can also be considered as a phenomenological consistency check of the soliton picture of baryons. (orig.)

Non-baryonic dark matter: observational evidence and detection methods

International Nuclear Information System (INIS)

Bergstroem, Lars

2000-01-01

The evidence for the existence of dark matter in the universe is reviewed. A general picture emerges, where both baryonic and non-baryonic dark matter is needed to explain current observations. In particular, a wealth of observational information points to the existence of a non-baryonic component, contributing between around 20 and 40% of the critical mass density needed to make the universe geometrically flat on large scales. In addition, an even larger contribution from vacuum energy (or cosmological constant) is indicated by recent observations. To the theoretically favoured particle candidates for non-baryonic dark matter belong axions, supersymmetric particles, and of less importance, massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. Direct and indirect methods for detection of supersymmetric dark matter are described in some detail. Present experiments are just reaching the required sensitivity to discover or rule out some of these candidates, and major improvements are planned over the coming years. (author)

Gluon saturation and baryon stopping in the SPS, RHIC, and LHC energy regions

International Nuclear Information System (INIS)

Li Shuang; Feng Shengqin

2012-01-01

A new geometrical scaling method with a gluon saturation rapidity limit is proposed to study the gluon saturation feature of the central rapidity region of relativistic nuclear collisions. The net-baryon number is essentially transported by valence quarks that probe the saturation regime in the target by multiple scattering. We take advantage of the gluon saturation model with geometric scaling of the rapidity limit to investigate net baryon distributions, nuclear stopping power and gluon saturation features in the SPS and RHIC energy regions. Predictions for net baryon rapidity distributions, mean rapidity loss and gluon saturation feature in central Pb + Pb collisions at the LHC are made in this paper. (authors)

Flavor-singlet baryons in the graded symmetry approach to partially quenched QCD

Science.gov (United States)

Hall, Jonathan M. M.; Leinweber, Derek B.

2016-11-01

Progress in the calculation of the electromagnetic properties of baryon excitations in lattice QCD presents new challenges in the determination of sea-quark loop contributions to matrix elements. A reliable estimation of the sea-quark loop contributions represents a pressing issue in the accurate comparison of lattice QCD results with experiment. In this article, an extension of the graded symmetry approach to partially quenched QCD is presented, which builds on previous theory by explicitly including flavor-singlet baryons in its construction. The formalism takes into account the interactions among both octet and singlet baryons, octet mesons, and their ghost counterparts; the latter enables the isolation of the quark-flow disconnected sea-quark loop contributions. The introduction of flavor-singlet states enables systematic studies of the internal structure of Λ -baryon excitations in lattice QCD, including the topical Λ (1405 ).

Hiding of the conserved (anti)baryonic charge into black holes

International Nuclear Information System (INIS)

Dolgov, A.D.

1980-01-01

The problem of the baryon asymmetry of the Universe is considered. It is suggested that the baryon asymmetry of the Universe is generated by black hole evaporation in a specific mechanism proposed by Zeldovich. Net amount of baryons evaporated by a black hole is shown can be unequal to that of antibaryons, even if the baryon charge is microscopically conserved. It is concluded that the discussed mechanism can provide the observed baryon assymetry of the Universe if primary black holes with the mass M=10sup(4+-2)Msub(P), where Msub(P)=10sup(19) GeV is the Planck mass, give noticeable contribution into the total energy density of the Universe

Vector mesons in meson-baryon scattering and large-N_c quantum chromodynamics

International Nuclear Information System (INIS)

Fuhrmann, Hans-Friedrich

2016-01-01

We examined strong interactions in the low-energy regime in terms of two complementary non-perturbative approaches: the interplay of large-N_c QCD and chiral perturbation theory was studied. While the expansion in the parameter 1/N_c is based on quark and gluon degrees of freedom, chiral perturbation theory uses hadrons as effective degrees of freedom. The focus of our work was the investigation of mesons and baryons composed from up-, down- and strange quarks. We used the chiral SU(3) Lagrangian with (J"P=(1)/(2)"+)- and (J"P=(3)/(2)"+)-baryon ground states as building blocks. In the SU(3)-flavour limit the latter form an octet and a decuplet, respectively. Studies in chiral perturbation theory hold a challenge: the chiral Lagrangian consists of an infinite number of terms. The treatment of low-energy QCD physics via a perturbation theory requires the ordering of these terms according to their relevance. We used the interplay between large-N_c QCD and chiral perturbation theory to shed light on the structure of the chiral Lagrangian. In the limit of large-N_c the low-energy parameters of the chiral Lagrangian are correlated. For instance the masses of the two baryon multiplets turn degenerate in the SU(3)-flavour limit. This serves as the starting point of our investigations. In this work we analysed the time-ordered product of two scalar and two vector currents in the baryon ground state. The examination of these matrix elements at large-N_c was compared to corresponding results derived in chiral perturbation theory. From this we obtained sum rules for some low-energy parameters of the chiral Lagrangian. The results for the vector correlation function were used to constrain a phenomenological interaction of light vector mesons with the baryon ground states. In the second part of this thesis we addressed a formal problem which arises in a partial wave decomposition of reaction amplitudes for particles with non-vanishing spin. In particular we considered the vector

Baryon Resonances

International Nuclear Information System (INIS)

Oset, E.; Sarkar, S.; Sun Baoxi; Vicente Vacas, M.J.; Ramos, A.; Gonzalez, P.; Vijande, J.; Martinez Torres, A.; Khemchandani, K.

2010-01-01

In this talk I show recent results on how many excited baryon resonances appear as systems of one meson and one baryon, or two mesons and one baryon, with the mesons being either pseudoscalar or vectors. Connection with experiment is made including a discussion on old predictions and recent results for the photoproduction of the Λ(1405) resonance, as well as the prediction of one 1/2 + baryon state around 1920 MeV which might have been seen in the γp→K + Λ reaction.

Quantum scattering from classical field theory

International Nuclear Information System (INIS)

Gould, T.M.; Poppitz, E.R.

1995-01-01

We show that scattering amplitudes between initial wave packet states and certain coherent final states can be computed in a systematic weak coupling expansion about classical solutions satisfying initial-value conditions. The initial-value conditions are such as to make the solution of the classical field equations amenable to numerical methods. We propose a practical procedure for computing classical solutions which contribute to high energy two-particle scattering amplitudes. We consider in this regard the implications of a recent numerical simulation in classical SU(2) Yang-Mills theory for multiparticle scattering in quantum gauge theories and speculate on its generalization to electroweak theory. We also generalize our results to the case of complex trajectories and discuss the prospects for finding a solution to the resulting complex boundary value problem, which would allow the application of our method to any wave packet to coherent state transition. Finally, we discuss the relevance of these results to the issues of baryon number violation and multiparticle scattering at high energies. ((orig.))

Pion-exchange contribution to the parity-violating asymmetry in pp scattering

International Nuclear Information System (INIS)

Silbar, R.R.; Kloet, W.M.; Kisslinger, L.S.; Dubach, J.

1988-01-01

Charged pion exchange, producing nΔ ++ intermediate states, contributes negatively to the weak scattering asymmetry in longitudinally-polarized pp scattering. Including this contribution moves the theoretical prediction away from the 800 MeV experimental datum. The pion-exchange contribution has both inelastic and elastic scattering components and is sizeable even below the pion production threshold. Strong distortions enhance the magnitude of the effect. 14 refs., 5 figs

Electromagnetic properties of light and heavy baryons in the relativistic quark model

International Nuclear Information System (INIS)

Nicmorus Marinescu, Diana

2007-01-01

One of the main challenges of nowadays low-energy physics remains the description of the internal structure of hadrons, strongly connected to the electromagnetic properties of matter. In this vein, the success of the relativistic quark model in the analysis of the hadron structure constitutes a solid motivation for the study carried out throughout this work. The relativistic quark model is extended to the investigation of static electromagnetic properties of both heavy and light baryons. The bare contributions to the magnetic moments of the single-, double- and triple-heavy baryons are calculated. Moreover, the relativistic quark model allows the study of the electromagnetic properties of the light baryon octet incorporating meson cloud contributions in a perturbative manner. The long disputed values of the multipole ratios E2/M1 and C2/M1 and the electromagnetic form factors of the N→Δγ transition are successfully reproduced. The relativistic quark model can be viewed as a quantum field theory approach based on a phenomenological Lagrangian coupling light and heavy baryons to their constituent quarks. In our approach the baryon is a composite object of three constituent quarks, at least in leading order. The effective interaction Lagrangian is written in terms of baryon and constituent quark fields. The effective action preserves Lorentz covariance and gauge invariance. The main ingredients of the model are already introduced at the level of the interaction Lagrangian: the three-quark baryon currents, the Gaussian distribution of the constituent quarks inside the baryon and the compositeness condition which sets an upper limit for the baryon-quark vertex. The S-matrix elements are expressed by a set of Feynman quark-diagrams. The model contains only few parameters, namely, the cut-off parameter of the Gaussian quark distribution and the free quark propagator, which are unambiguously determined from the best fit to the data. The heavy quark limit within this

Electromagnetic properties of light and heavy baryons in the relativistic quark model

Energy Technology Data Exchange (ETDEWEB)

Nicmorus Marinescu, Diana

2007-06-14

One of the main challenges of nowadays low-energy physics remains the description of the internal structure of hadrons, strongly connected to the electromagnetic properties of matter. In this vein, the success of the relativistic quark model in the analysis of the hadron structure constitutes a solid motivation for the study carried out throughout this work. The relativistic quark model is extended to the investigation of static electromagnetic properties of both heavy and light baryons. The bare contributions to the magnetic moments of the single-, double- and triple-heavy baryons are calculated. Moreover, the relativistic quark model allows the study of the electromagnetic properties of the light baryon octet incorporating meson cloud contributions in a perturbative manner. The long disputed values of the multipole ratios E2/M1 and C2/M1 and the electromagnetic form factors of the N{yields}{delta}{gamma} transition are successfully reproduced. The relativistic quark model can be viewed as a quantum field theory approach based on a phenomenological Lagrangian coupling light and heavy baryons to their constituent quarks. In our approach the baryon is a composite object of three constituent quarks, at least in leading order. The effective interaction Lagrangian is written in terms of baryon and constituent quark fields. The effective action preserves Lorentz covariance and gauge invariance. The main ingredients of the model are already introduced at the level of the interaction Lagrangian: the three-quark baryon currents, the Gaussian distribution of the constituent quarks inside the baryon and the compositeness condition which sets an upper limit for the baryon-quark vertex. The S-matrix elements are expressed by a set of Feynman quark-diagrams. The model contains only few parameters, namely, the cut-off parameter of the Gaussian quark distribution and the free quark propagator, which are unambiguously determined from the best fit to the data. The heavy quark limit

Baryons and baryonic matter in the large Nc and heavy quark limits

International Nuclear Information System (INIS)

Cohen, Thomas D.; Kumar, Nilay; Ndousse, Kamal K.

2011-01-01

This paper explores properties of baryons and finite density baryonic matter in an artificial world in which N c , the number of colors, is large and the quarks of all species are degenerate and much larger than Λ QCD . It has long been known that in large N c quantum chromodynamics (QCD), baryons composed entirely of heavy quarks are accurately described in the mean-field approximation. However, the detailed properties of baryons in the combined large N c and heavy-quark limits have not been fully explored. Here some basic properties of baryons are computed using a variational approach. At leading order in both the large N c and heavy-quark expansions the baryon mass is shown to be M baryon ≅N c M Q (1-0.054 26α-tilde s 2 ), where α-tilde s ≡N c α s . The baryon form factor is also computed. Baryonic matter, the analog of nuclear matter in this artificial world, should also be well described in the mean-field approximation. In the special case where all baryons have an identical spin-flavor structure, it is shown that in the formal heavy-quark and large N c limit interactions between baryons are strictly repulsive at low densities. The energy per baryon is computed in this limit and found to be exponentially small. It is shown that when the restriction to baryons with an identical spin-flavor structure is dropped, a phase of baryonic matter exists with a density of 2N f times that for the restricted case but with the same energy (where N f is the number of degenerate flavors). It is shown that this phase is at least metastable.

Experimental plan of Σp scatterings at J-PARC

Directory of Open Access Journals (Sweden)

Tamura H.

2012-02-01

Full Text Available In order to test theoretical frameworks of the baryon-baryon interactions and to confirm the ”Pauli effect between quarks” for the first time, we propose an experiment to measure low-energy hyperon proton scattering cross sections in the following channels with high statistics, 1. Σ− p elastic scattering, 2. Σ− p → Λn inelastic scattering, 3. Σ+ p elastic scattering. According to theoretical models based on quark-gluon picture for the short range part of the baryon-baryon interactions, the Σ+ p channel is expected to have an extremely repulsive core due to the Pauli effect between quarks, which leads a Σ+ p cross section twice as large as that predicted by conventional meson exchange models with a phenomenologically treated short range repulsive core. In addition, measurement of the Σ− p channel where the quark Pauli effect is not effective is also necessary to test the present theoretical models based on meson exchange picture with the flavor SU(3 symmetry. Thus this experiment will provide essential data to test the frameworks of the theoretical models of the baryon-baryon interactions and to investigate the nature of the repulsive core which has not been understood yet. In order to overcome the experimental difficulties in measuring low-energy hyperon proton scattering, we will use a new experimental technique in which a liquid H2 target is used as hyperon production and hyperon scattering targets with a detector system surrounding the LH2 target for detection of a scattered proton and a decay product from a hyperon. The hyperon scattering event is kinematically identified. Because imaging detectors used in past experiments are not employed, high intensity π beam can be used, allowing us to take high statistics data of 100 times more than the previous experiments. We have proposed an experiment of Σp scattering at the K1.8 beam line by utilizing the K1.8 beam line spectrometer and the SKS spectrometer. A high intensity �

Molecular dynamics simulation for the baryon-quark phase transition at finite baryon density

International Nuclear Information System (INIS)

Akimura, Y.; Maruyama, T.; Chiba, S.; Yoshinaga, N.

2005-01-01

We study the baryon-quark phase transition in the molecular dynamics (MD) of the quark degrees of freedom at finite baryon density. The baryon state at low baryon density, and the deconfined quark state at high baryon density are reproduced. We investigate the equations of state of matters with different u-d-s compositions. It is found that the baryon-quark transition is sensitive to the quark width. (orig.)

Hyperfine splitting of low-lying heavy baryons

Energy Technology Data Exchange (ETDEWEB)

Harada, M.; Qamar, A.; Schechter, J. [Syracuse Univ., NY (United States). Dept. of Physics; Sannino, F. [Syracuse Univ., NY (United States). Dept. of Physics]|[Dipartimento di Scienze Fisiche and Istituto Nazionale di Fisica Nucleare, Mostra D`Oltremare Pad. 19, 80125, Napoli (Italy); Weigel, H. [Institute for Theoretical Physics, Tuebingen University, Auf der Morgenstelle 14, D-72076, Tuebingen (Germany)

1997-11-10

We calculate the next-to-leading order contribution to the masses of the heavy baryons in the bound-state approach for baryons containing a heavy quark. These 1/N{sub C} corrections arise when states of good spin and isospin are generated from the background soliton of the light meson fields. Our study is motivated by the previously established result that light vector meson fields are required for this soliton in order to reasonably describe the spectrum of both the light and the heavy baryons. We note that the inclusion of light vector mesons significantly improves the agreement of the predicted hyperfine splitting with experiment. A number of aspects of this somewhat complicated calculation are discussed in detail. (orig.). 33 refs.

The Inner Regions of Disk Galaxies: A Constant Baryonic Fraction?

Directory of Open Access Journals (Sweden)

Federico Lelli

2014-07-01

Full Text Available For disk galaxies (spirals and irregulars, the inner circular-velocity gradient dRV0 (inner steepness of the rotation curve correlates with the central surface brightness ∑*,0 with a slope of ~0.5. This implies that the central dynamical mass density scales almost linearly with the central baryonic density. Here I show that this empirical relation is consistent with a simple model where the central baryonic fraction ƒbar,0 is fixed to 1 (no dark matter and the observed scatter is due to differences in the baryonic mass-to-light ratio Mbar / LR (ranging from 1 to 3 in the R-band and in the characteristic thickness of the central stellar component Δz (ranging from 100 to 500 pc. Models with lower baryonic fractions are possible, although they require some fine-tuning in the values of Mbar/LR and Δz. Regardless of the actual value of ƒbar,0, the fact that different types of galaxies do not show strong variations in ƒbar,0 is surprising, and may represent a challenge for models of galaxy formation in a Λ Cold Dark Matter (ΛCDM cosmology.

Baryon interactions from lattice QCD with physical masses — strangeness S = -1 sector —

Science.gov (United States)

Nemura, Hidekatsu; Aoki, Sinya; Doi, Takumi; Gongyo, Shinya; Hatsuda, Tetsuo; Ikeda, Yoichi; Inoue, Takashi; Iritani, Takumi; Ishii, Noriyoshi; Miyamoto, Takaya; Sasaki, Kenji

2018-03-01

We present our recent results of baryon interactions with strangeness S = -1 based on Nambu-Bethe-Salpeter (NBS) correlation functions calculated fromlattice QCD with almost physical quark masses corresponding to (mk,mk) ≈ (146, 525) MeV and large volume (La)4 ≈ (96a)4 ≈ (8.1 fm)4. In order to perform a comprehensive study of baryon interactions, a large number of NBS correlation functions from NN to ΞΞ are calculated simultaneously by using large scale computer resources. In this contribution, we focus on the strangeness S = -1 channels of the hyperon interactions by means of HAL QCD method. Four sets of three potentials (the 3S1 - 3 D1 central, 3S1 - 3 D1 tensor, and the 1S0 central potentials) are presented for the ∑N - ∑N (the isospin I = 3/2) diagonal, the ∧N - ∧N diagonal, the ∧N → ∑N transition, and the ∑N - ∑N (I = 1/2) diagonal interactions. Scattering phase shifts for ∑N (I = 3/2) system are presented.

Baryons and baryonic matter in four-fermion interaction models

International Nuclear Information System (INIS)

Urlichs, K.

2007-01-01

In this work we discuss baryons and baryonic matter in simple four-fermion interaction theories, the Gross-Neveu model and the Nambu-Jona-Lasinio model in 1+1 and 2+1 space-time dimensions. These models are designed as toy models for dynamical symmetry breaking in strong interaction physics. Pointlike interactions (''four-fermion'' interactions) between quarks replace the full gluon mediated interaction of quantum chromodynamics. We consider the limit of a large number of fermion flavors, where a mean field approach becomes exact. This method is formulated in the language of relativistic many particle theory and is equivalent to the Hartree-Fock approximation. In 1+1 dimensions, we generalize known results on the ground state to the case where chiral symmetry is broken explicitly by a bare mass term. For the Gross-Neveu model, we derive an exact self-consistent solution for the finite density ground state, consisting of a one-dimensional array of equally spaced potential wells, a baryon crystal. For the Nambu- Jona-Lasinio model we apply the derivative expansion technique to calculate the total energy in powers of derivatives of the mean field. In a picture akin to the Skyrme model of nuclear physics, the baryon emerges as a topological soliton. The solution for both the single baryon and dense baryonic matter is given in a systematic expansion in powers of the pion mass. The solution of the Hartree-Fock problem is more complicated in 2+1 dimensions. In the massless Gross-Neveu model we derive an exact self-consistent solution by extending the baryon crystal of the 1+1 dimensional model, maintaining translational invariance in one spatial direction. This one-dimensional configuration is energetically degenerate to the translationally invariant solution, a hint in favor of a possible translational symmetry breakdown by more general geometrical structures. In the Nambu-Jona-Lasinio model, topological soliton configurations induce a finite baryon number. In contrast

Baryons and baryonic matter in four-fermion interaction models

Energy Technology Data Exchange (ETDEWEB)

Urlichs, K.

2007-02-23

In this work we discuss baryons and baryonic matter in simple four-fermion interaction theories, the Gross-Neveu model and the Nambu-Jona-Lasinio model in 1+1 and 2+1 space-time dimensions. These models are designed as toy models for dynamical symmetry breaking in strong interaction physics. Pointlike interactions (''four-fermion'' interactions) between quarks replace the full gluon mediated interaction of quantum chromodynamics. We consider the limit of a large number of fermion flavors, where a mean field approach becomes exact. This method is formulated in the language of relativistic many particle theory and is equivalent to the Hartree-Fock approximation. In 1+1 dimensions, we generalize known results on the ground state to the case where chiral symmetry is broken explicitly by a bare mass term. For the Gross-Neveu model, we derive an exact self-consistent solution for the finite density ground state, consisting of a one-dimensional array of equally spaced potential wells, a baryon crystal. For the Nambu- Jona-Lasinio model we apply the derivative expansion technique to calculate the total energy in powers of derivatives of the mean field. In a picture akin to the Skyrme model of nuclear physics, the baryon emerges as a topological soliton. The solution for both the single baryon and dense baryonic matter is given in a systematic expansion in powers of the pion mass. The solution of the Hartree-Fock problem is more complicated in 2+1 dimensions. In the massless Gross-Neveu model we derive an exact self-consistent solution by extending the baryon crystal of the 1+1 dimensional model, maintaining translational invariance in one spatial direction. This one-dimensional configuration is energetically degenerate to the translationally invariant solution, a hint in favor of a possible translational symmetry breakdown by more general geometrical structures. In the Nambu-Jona-Lasinio model, topological soliton configurations induce a finite baryon

Charge radii of octet and decuplet baryons in chiral constituent ...

Indian Academy of Sciences (India)

in electron–baryon scattering experiments [4,5] giving rp = 0.877 ± 0.007 fm ... breaking of the SU(3) symmetry and a non-vanishing neutron charge mean square radius ... QCD Lagrangian is not invariant under the chiral transformation. ... of a constituent quark GBs [34–37], successfully explains the 'proton spin problem'.

Baryons as solitons

International Nuclear Information System (INIS)

Walliser, Hans

2000-01-01

Chiral Lagrangians as effective field theories of QCD are successfully applied to meson physics in the framework of chiral perturbation theory. Because of their nonlinear structure these Lagrangians allow for static soliton solutions interpreted as baryons. Their semiclassical quantization, which provides the leading order in an 1/N C expansion with N C the number of colors, turned out to be insufficient to obtain satisfactory agreement with empirical baryon observables. However with N C =3, large corrections are expected in the next-to-leading order carried by mesonic fluctuations around the soliton background, which require renormalization to 1-loop. In contrast to chiral perturbation theory, the low-energy Lagrangian proves inapt and terms with an arbitrary number of gradients may in principle contribute. Assumptions about the a priori unknown higher chiral orders are tested by the scale-dependence of the results. For example, in the simple Sine-Gordon model with 1 scalar field in 1+1 dimensions, knowledge of the low-energy behavior together with the mere existence of an underlying 1-loop renormalizable scale-independent solitonic theory is sufficient to regain the full solution. Baryonic observables calculated within that framework generally lead to better agreement with experiment except for the axial quantities. For these quantities the 1/N C expansion does not converge sufficiently fast because the current algebra mixes different N C orders

Extracting scattering phase shifts in higher partial waves from lattice QCD calculations

Energy Technology Data Exchange (ETDEWEB)

Luu, Thomas; Savage, Martin J.

2011-06-01

Lüscher’s method is routinely used to determine meson-meson, meson-baryon, and baryon-baryon s-wave scattering amplitudes below inelastic thresholds from lattice QCD calculations—presently at unphysical light-quark masses. In this work we review the formalism and develop the requisite expressions to extract phase shifts describing meson-meson scattering in partial waves with angular momentum l≤6 and l=9. The implications of the underlying cubic symmetry, and strategies for extracting the phase shifts from lattice QCD calculations, are presented, along with a discussion of the signal-to-noise problem that afflicts the higher partial waves.

Baryon and meson phenomenology in the extended Linear Sigma Model

Energy Technology Data Exchange (ETDEWEB)

Giacosa, Francesco; Habersetzer, Anja; Teilab, Khaled; Eshraim, Walaa; Divotgey, Florian; Olbrich, Lisa; Gallas, Susanna; Wolkanowski, Thomas; Janowski, Stanislaus; Heinz, Achim; Deinet, Werner; Rischke, Dirk H. [Institute for Theoretical Physics, J. W. Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Kovacs, Peter; Wolf, Gyuri [Institute for Particle and Nuclear Physics, Wigner Research Center for Physics, Hungarian Academy of Sciences, H-1525 Budapest (Hungary); Parganlija, Denis [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, A-1040 Vienna (Austria)

2014-07-01

The vacuum phenomenology obtained within the so-called extended Linear Sigma Model (eLSM) is presented. The eLSM Lagrangian is constructed by including from the very beginning vector and axial-vector d.o.f., and by requiring dilatation invariance and chiral symmetry. After a general introduction of the approach, particular attention is devoted to the latest results. In the mesonic sector the strong decays of the scalar and the pseudoscalar glueballs, the weak decays of the tau lepton into vector and axial-vector mesons, and the description of masses and decays of charmed mesons are shown. In the baryonic sector the omega production in proton-proton scattering and the inclusion of baryons with strangeness are described.

Search for a narrow baryonic resonance decaying to Ks0p or Ks0p¯ in deep inelastic scattering at HERA

Science.gov (United States)

H1 Collaboration; Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Flucke, G.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A. J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, M.; Usik, A.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

2006-08-01

A search for a narrow baryonic resonance decaying to Ks0p or Ks0p¯ is carried out in deep inelastic ep scattering with the H1 detector at HERA. Such a resonance could be a strange pentaquark Θ, evidence for which has been reported by several experiments. The Ks0p and Ks0p¯ invariant mass distributions presented here do not show any significant peak in the mass range from threshold up to 1.7 GeV. Mass dependent upper limits on σ(ep→eΘX)×BR(Θ→Kp) are obtained at the 95% confidence level.

Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

Energy Technology Data Exchange (ETDEWEB)

Dvali, Gia [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Gußmann, Alexander, E-mail: alexander.gussmann@physik.uni-muenchen.de [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany)

2016-12-15

We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.

Subhalo demographics in the Illustris simulation: effects of baryons and halo-to-halo variation

Science.gov (United States)

Chua, Kun Ting Eddie; Pillepich, Annalisa; Rodriguez-Gomez, Vicente; Vogelsberger, Mark; Bird, Simeon; Hernquist, Lars

2017-12-01

We study the abundance of subhaloes in the hydrodynamical cosmological simulation Illustris, which includes both baryons and dark matter in a cold dark matter volume 106.5 Mpc a side. We compare Illustris to its dark-matter only (DMO) analogue, Illustris-Dark and quantify the effects of baryonic processes on the demographics of subhaloes in the host mass range 1011-3 × 1014 M⊙. We focus on both the evolved (z = 0) subhalo cumulative mass functions (SHMF) and the statistics of subhaloes ever accreted, i.e. infall SHMF. We quantify the variance in subhalo abundance at fixed host mass and investigate the physical reasons responsible for such scatter. We find that in Illustris, baryonic physics impacts both the infall and z = 0 subhalo abundance by tilting the DMO function and suppressing the abundance of low-mass subhaloes. The breaking of self-similarity in the subhalo abundance at z = 0 is enhanced by the inclusion of baryonic physics. The non-monotonic alteration of the evolved subhalo abundances can be explained by the modification of the concentration-mass relation of Illustris hosts compared to Illustris-Dark. Interestingly, the baryonic implementation in Illustris does not lead to an increase in the halo-to-halo variation compared to Illustris-Dark. In both cases, the normalized intrinsic scatter today is larger for Milky Way-like haloes than for cluster-sized objects. For Milky Way-like haloes, it increases from about eight per cent at infall to about 25 per cent at the current epoch. In both runs, haloes of fixed mass formed later host more subhaloes than early formers.

Quark potential model of baryon spin-orbit mass splittings

International Nuclear Information System (INIS)

Wang Fan; Wong Chunwa

1987-01-01

We show that it is possible to make the P-wave spin-orbit mass splittings in Λ baryons consistent with those of nonstrange baryons in a naive quark model, but only by introducing additional terms in the quark-quark effective interaction. These terms might be related to contributions due to pomeron exchange and sea excitations. The implications of our model in meson spectroscopy and nuclear forces are discussed. (orig.)

Vector mesons in meson-baryon scattering and large-N{sub c} quantum chromodynamics

Energy Technology Data Exchange (ETDEWEB)

Fuhrmann, Hans-Friedrich

2016-02-11

We examined strong interactions in the low-energy regime in terms of two complementary non-perturbative approaches: the interplay of large-N{sub c} QCD and chiral perturbation theory was studied. While the expansion in the parameter 1/N{sub c} is based on quark and gluon degrees of freedom, chiral perturbation theory uses hadrons as effective degrees of freedom. The focus of our work was the investigation of mesons and baryons composed from up-, down- and strange quarks. We used the chiral SU(3) Lagrangian with (J{sup P}=(1)/(2){sup +})- and (J{sup P}=(3)/(2){sup +})-baryon ground states as building blocks. In the SU(3)-flavour limit the latter form an octet and a decuplet, respectively. Studies in chiral perturbation theory hold a challenge: the chiral Lagrangian consists of an infinite number of terms. The treatment of low-energy QCD physics via a perturbation theory requires the ordering of these terms according to their relevance. We used the interplay between large-N{sub c} QCD and chiral perturbation theory to shed light on the structure of the chiral Lagrangian. In the limit of large-N{sub c} the low-energy parameters of the chiral Lagrangian are correlated. For instance the masses of the two baryon multiplets turn degenerate in the SU(3)-flavour limit. This serves as the starting point of our investigations. In this work we analysed the time-ordered product of two scalar and two vector currents in the baryon ground state. The examination of these matrix elements at large-N{sub c} was compared to corresponding results derived in chiral perturbation theory. From this we obtained sum rules for some low-energy parameters of the chiral Lagrangian. The results for the vector correlation function were used to constrain a phenomenological interaction of light vector mesons with the baryon ground states. In the second part of this thesis we addressed a formal problem which arises in a partial wave decomposition of reaction amplitudes for particles with non

One-baryon spectrum and analytical properties of one-baryon dispersion curves in 3 + 1 dimensional strongly coupled lattice QCD with three flavors

International Nuclear Information System (INIS)

Faria da Veiga, Paulo A.; O’Carroll, Michael; Valencia Alvites, José C.

2016-01-01

Considering a 3 + 1 dimensional lattice quantum chromodynamics (QCD) model defined with the improved Wilson action, three flavors, and 4 × 4 Dirac spin matrices, in the strong coupling regime, we reanalyze the question of the existence of the eightfold way baryons and complete our previous work where the existence of isospin octet baryons was rigorously solved. Here, we show the existence of isospin decuplet baryons which are associated with isolated dispersion curves in the subspace of the underlying quantum mechanical Hilbert space with vectors constructed with an odd number of fermion and antifermion basic quark and antiquark fields. Moreover, smoothness properties for these curves are obtained. The present work deals with a case for which the traditional method to solve the implicit equation for the dispersion curves, based on the use of the analytic implicit function theorem, cannot be applied. We do not have only one but two solutions for each one-baryon decuplet sector with fixed spin third component. Instead, we apply the Weierstrass preparation theorem, which also provides a general method for the general degenerate case. This work is completed by analyzing a spectral representation for the two-baryon correlations and providing the leading behaviors of the field strength normalization and the mass of the spectral contributions with more than one-particle. These are needed results for a rigorous analysis of the two-baryon and meson-baryon particle spectra.

One-baryon spectrum and analytical properties of one-baryon dispersion curves in 3 + 1 dimensional strongly coupled lattice QCD with three flavors

Energy Technology Data Exchange (ETDEWEB)

Faria da Veiga, Paulo A., E-mail: veiga@icmc.usp.br; O’Carroll, Michael, E-mail: michaelocarroll@gmail.com; Valencia Alvites, José C., E-mail: cien.mat@hotmail.com [Departamento de Matemática Aplicada e Estatística, ICMC, USP-São Carlos, C.P. 668, São Carlos, SP 13560-970 (Brazil)

2016-03-15

Considering a 3 + 1 dimensional lattice quantum chromodynamics (QCD) model defined with the improved Wilson action, three flavors, and 4 × 4 Dirac spin matrices, in the strong coupling regime, we reanalyze the question of the existence of the eightfold way baryons and complete our previous work where the existence of isospin octet baryons was rigorously solved. Here, we show the existence of isospin decuplet baryons which are associated with isolated dispersion curves in the subspace of the underlying quantum mechanical Hilbert space with vectors constructed with an odd number of fermion and antifermion basic quark and antiquark fields. Moreover, smoothness properties for these curves are obtained. The present work deals with a case for which the traditional method to solve the implicit equation for the dispersion curves, based on the use of the analytic implicit function theorem, cannot be applied. We do not have only one but two solutions for each one-baryon decuplet sector with fixed spin third component. Instead, we apply the Weierstrass preparation theorem, which also provides a general method for the general degenerate case. This work is completed by analyzing a spectral representation for the two-baryon correlations and providing the leading behaviors of the field strength normalization and the mass of the spectral contributions with more than one-particle. These are needed results for a rigorous analysis of the two-baryon and meson-baryon particle spectra.

Baryon Budget of the Hot Circumgalactic Medium of Massive Spiral Galaxies

Science.gov (United States)

Li, Jiang-Tao; Bregman, Joel N.; Wang, Q. Daniel; Crain, Robert A.; Anderson, Michael E.

2018-03-01

The baryon content around local galaxies is observed to be much less than is needed in Big Bang nucleosynthesis. Simulations indicate that a significant fraction of these “missing baryons” may be stored in a hot tenuous circumgalactic medium (CGM) around massive galaxies extending to or even beyond the virial radius of their dark matter halos. Previous observations in X-ray and Sunyaev–Zel’dovich (SZ) signals claimed that ∼(1–50)% of the expected baryons are stored in a hot CGM within the virial radius. The large scatter is mainly caused by the very uncertain extrapolation of the hot gas density profile based on the detection in a small radial range (typically within 10%–20% of the virial radius). Here, we report stacking X-ray observations of six local isolated massive spiral galaxies from the CGM-MASS sample. We find that the mean density profile can be characterized by a single power law out to a galactocentric radius of ≈200 kpc (or ≈130 kpc above the 1σ background uncertainty), about half the virial radius of the dark matter halo. We can now estimate that the hot CGM within the virial radius accounts for (8 ± 4)% of the baryonic mass expected for the halos. Including the stars, the baryon fraction is (27 ± 16)%, or (39 ± 20)% by assuming a flattened density profile at r ≳ 130 kpc. We conclude that the hot baryons within the virial radius of massive galaxy halos are insufficient to explain the “missing baryons.”

Search for a Narrow Baryonic Resonance Decaying to $K^0_s p$ or $K^0_s \\bar{p}$ in Deep Inelastic Scattering at HERA

OpenAIRE

Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.

2006-01-01

A search for a narrow baryonic resonance decaying to $K^0_s p$ or $K^0_s \\bar p$ is carried out in deep inelastic ep scattering with the H1 detector at HERA. Such a resonance could be a strange pentaquark \\thplns, evidence for which has been reported by several experiments. The $K^0_s p$ and $K^0_s \\bar p$ invariant mass distributions presented here do not show any significant peak in the mass range from threshold up to 1.7 GeV. Mass dependent upper limits on $\\sigma(ep \\to e \\thplf X)\\times ...

Spin-directed momentum transfers in SIDIS baryon production

International Nuclear Information System (INIS)

Sivers, D.

2016-01-01

The measurement of transverse single-spin asymmetries for baryon production in the target fragmentation region of semi-inclusive deep-inelastic scattering (SIDIS), can produce important insight into those nonperturbative aspects of QCD directly associated with confinement and with the dynamical breaking of chiral symmetry. We discuss here, in terms of spin-directed momentum transfers, the powerful quantum field- theoretical constraints on the spin-orbit dynamics underlying these transverse spin observables. The A τ -odd spin-directed momentum shifts, originating either in the target nucleon (δk TN ) or in the QCD jets (δp TN ) produced in the deep inelastic scattering process, represent significant quantum entanglement effects connecting information from current fragmentation with observables in target fragmentation. (author)

Dynamically generated resonances from the vector octet-baryon octet interaction

Energy Technology Data Exchange (ETDEWEB)

Oset, E. [Institutos de Investigacion de Paterna, Departamento de Fisica Teorica e IFIC, Centro Mixto Universidad de Valencia-CSIC, Valencia (Spain); Ramos, A. [Universitat de Barcelona, Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Barcelona (Spain)

2010-06-15

We study the interaction of vector mesons with the octet of stable baryons in the framework of the local hidden gauge formalism using a coupled-channels unitary approach. We examine the scattering amplitudes and their poles, which can be associated to known J{sup P}=1/2{sup -}, 3/2{sup -} baryon resonances, in some cases, or give predictions in other ones. The formalism employed produces doublets of degenerate J{sup P}= 1/2{sup -}, 3/2{sup -} states, a pattern which is observed experimentally in several cases. The findings of this work should also be useful to guide present experimental programs searching for new resonances, in particular in the strange sector where the current information is very poor. (orig.)

Searching for baryons

International Nuclear Information System (INIS)

Majumdar, Subhabrata

2015-01-01

The current precision cosmological measurements, in agreement with big bang nucleosynthesis studies, tell us that approximately 95 percent of the Universe is 'dark' and only 5 percent of the Universe is 'visible' which comprises of baryons. However, observations reveal only a small fraction of this baryon budget. A key cosmological question arises as to 'where are these missing baryons?'. Simulations and past observations suggest that some of these are in the diffuse cosmic web. Recently, they have been observed, and speculated, to be hiding in the outskirts of massive halos, from Milky Way type galaxies to clusters. Upcoming surveys have the potential to unravel the mystery of the missing baryons. (author)

Baryon interactions from lattice QCD with physical masses — strangeness S = -1 sector —

Directory of Open Access Journals (Sweden)

Nemura Hidekatsu

2018-01-01

Full Text Available We present our recent results of baryon interactions with strangeness S = −1 based on Nambu-Bethe-Salpeter (NBS correlation functions calculated fromlattice QCD with almost physical quark masses corresponding to (mk,mk ≈ (146, 525 MeV and large volume (La4 ≈ (96a4 ≈ (8.1 fm4. In order to perform a comprehensive study of baryon interactions, a large number of NBS correlation functions from NN to ΞΞ are calculated simultaneously by using large scale computer resources. In this contribution, we focus on the strangeness S = −1 channels of the hyperon interactions by means of HAL QCD method. Four sets of three potentials (the 3S1 − 3 D1 central, 3S1 − 3 D1 tensor, and the 1S0 central potentials are presented for the ∑N − ∑N (the isospin I = 3/2 diagonal, the ∧N − ∧N diagonal, the ∧N → ∑N transition, and the ∑N − ∑N (I = 1/2 diagonal interactions. Scattering phase shifts for ∑N (I = 3/2 system are presented.

Test of right-handed currents in baryon semileptonic decays

International Nuclear Information System (INIS)

Garcia, A.; Huerta, R.; Maya, M.; Perez Marcial, R.

1985-01-01

The effect of a right-handed boson on baryon semileptonic decay is considered. The analysis of polarized and unpolarized decays is carried out and it is shown that the best place to look for a right-handed current (RHC) signature is in polarized baryon decay. However, our results are useful for high statistics experiments. In order to see the contribution of the right-handed currents in the case of unpolarized hyperon decay, the Cabibbo theory should be assumed. (orig.)

Investigation of doubly heavy baryon production at e+e- colliders

International Nuclear Information System (INIS)

Ma, J.P.; Si, Z.G.

2004-01-01

In this talk, we investigate the doubly heavy baryon production by factorizing nonperturbative- and perturbative effects: A pair of heavy quarks can be produced perturbatively and then the pair is transformed into the baryon. The transformation is nonperturbative. Since a heavy quark moves with a small velocity in the baryon in its rest frame, NRQCD can be used to describe the transformation. At the leading order, the baryon is found to be formed from two states of the heavy-quark pair, one state is with the pair in 3 S 1 state and in color 3-bar, another is with the pair in 1 S 0 state and in color 6. Two matrix elements are defined for the transformation from the two states, and their perturbative coefficients in the contribution to the cross-section at a e + e - collider are calculated. (author)

Baryonic dark matter

International Nuclear Information System (INIS)

Uson, Juan M.

2000-01-01

Many searches for baryonic dark matter have been conducted but, so far, all have been unsuccessful. Indeed, no more than 1% of the dark matter can be in the form of hydrogen burning stars. It has recently been suggested that most of the baryons in the universe are still in the form of ionized gas so that it is possible that there is no baryonic dark matter. Although it is likely that a significant fraction of the dark matter in the Milky Way is in a halo of non-baryonic matter, the data do not exclude the possibility that a considerable amount, perhaps most of it, could be in a tenuous halo of diffuse ionized gas

Baryon Anomaly in Heavy-Ion Collisions and Colour Correlations in QGP

CERN Document Server

Levin, Eugene M; Ryskin, Mikhail G; Safarik, Karel

2013-01-01

A baryon anomaly – an increased baryon-to-meson production ratio at intermediate pT in heavyion collisions when compared to pp collisions – is observed at RHIC and the LHC. This effect is usually explained by recombination of constituent quarks during QGP hadronization, or as a consequence of a strong radial flow developed during the heavy-ion collision. In this contribution, an additional mechanism to favour baryon over meson production is proposed: when hadrons are formed in the recombination of nearby quarks and antiquarks, only colour-singlet combinations can be chosen. Hadron formation, in particular the probability to create baryons or mesons, depends on the distribution of colour charges among quarks. If the distribution is random – a reasonable assumption for Quark–Gluon Plasma (QGP) – the baryon-to-meson ratio is nearly twice higher than in the situation where quark colours are pre-arranged to obtain a white hadron in the combination of nearest quarks and antiquarks. The correlation of colo...

Neutron-antineutron oscillation and baryonic majoron: low scale spontaneous baryon violation

Energy Technology Data Exchange (ETDEWEB)

Berezhiani, Zurab [Universita dell' Aquila, Dipartimento delle Scienze Fisiche e Chimiche, L' Aquila (Italy); INFN, Laboratori Nazionali Gran Sasso, L' Aquila (Italy)

2016-12-15

We discuss the possibility that baryon number B is spontaneously broken at low scales, of the order of MeV or even smaller, inducing the neutron-antineutron oscillation at the experimentally accessible level. An associated Goldstone particle-baryonic majoron can have observable effects in neutron to antineutron transitions in nuclei or dense nuclear matter. By extending baryon number to an anomaly-free B - L symmetry, the baryo-majoron can be identified with the ordinary majoron associated with the spontaneous breaking of lepton number, and it can have interesting implications for neutrinoless 2β decay with the majoron emission. We also discuss the hypothesis that baryon number can be spontaneously broken by QCD itself via the six-quark condensates. (orig.)

Time delayed K sup + N reactions and exotic baryon resonances

CERN Document Server

Kelkar, N G; Khemchandani, K P

2003-01-01

Evidence and hints, from both the theoretical and experimental sides, of exotic baryon resonances with B = S, have been with us for the last 30 years. The poor status of the general acceptance of these Z* resonances is partly due to the prejudice against penta-quark baryons and partly due to the opinion that a proof of the existence of exotic states must be rigorous. This can refer to the quality and amount of data gathered, and also to the analytical methods applied in the study of these resonances. It then seems mandatory that all possibilities and aspects be exploited. We do that by analysing the time delay in K sup + N scattering, encountering clear signals of the exotic Z* resonances close to the pole values found in partial wave analyses.

Search for narrow baryon resonances (of masses through 3.4 and 5 GeV) through a π-p large angle elastic scattering formation experiment

International Nuclear Information System (INIS)

Chauveau, J.

1981-01-01

This work describes a search for narrow baryon resonances (of masses between 3.4 and 5 GeV) through a π - p large angle elastic scattering formation experiment. An optimization of the sensitivity of the experiment to detect resonances is obtained by the measurement of the central part of the angular distribution (/cos theta*/ -4 . The apparatus and data analysis are described in details. No narrow resonance has been found, the sensitivity of the experiment being characterized by a width GAMMA approximately equal to 1 MeV and an elasticity x approximately equal to 0.01. Finally, the differential cross section measurement is compared to some parton models [fr

Search for a Narrow Baryonic Resonance Decaying to $K^0_s p$ or $K^0_s \\bar{p}$ in Deep Inelastic Scattering at HERA

CERN Document Server

Aktas, A.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Flucke, G.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A.J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Toll, T.; Tomasz, F.; Traynor, D.; Truol, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, Marcel; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

2006-01-01

A search for a narrow baryonic resonance decaying to $K^0_s p$ or $K^0_s \\bar p$ is carried out in deep inelastic ep scattering with the H1 detector at HERA. Such a resonance could be a strange pentaquark \\thplns, evidence for which has been reported by several experiments. The $K^0_s p$ and $K^0_s \\bar p$ invariant mass distributions presented here do not show any significant peak in the mass range from threshold up to 1.7 GeV. Mass dependent upper limits on $\\sigma(ep \\to e \\thplf X)\\times BR(\\thplf \\to K^0 p)$ are obtained at the 95% confidence level.

Baryons and dual unitarization

International Nuclear Information System (INIS)

Konishi, K.-I.

1977-05-01

Processes involving baryons are discussed in the scheme of dual unitarization. In particular, the topological expansion is generalized to any hadronic S-matrix elements involving baryons and/or mesons. The expansion is based on a model for the baryon propagator, which is a set of three planar Feynman diagrams joined at a junction line. The resulting expansion is a double expansion in 1/N (N = the number of quark flavours) and in the number of baryon loops. Based on this, several new observations are made in phenomenological problems, and a unifying point of view in stressed. The scheme is evidently crossing invariant, and unitarity constraints are imposed order by order in 1/N and in the baryon loop number. (author)

Baryonic dark matter

International Nuclear Information System (INIS)

Lynden-Bell, D.; Gilmore, G.

1990-01-01

Dark matter, first definitely found in the large clusters of galaxies, is now known to be dominant mass in the outer parts of galaxies. All the mass definitely deduced could be made up of baryons, and this would fit well with the requirements of nucleosynthesis in a big bang of small Ω B . However, if inflation is the explanation of the expansion and large scale homogeneity of the universe and of baryon synthesis, and if the universe did not have an infinite extent at the big bang, then Ω should be minutely greater than unity. It is commonly hypothesized that most mass is composed of some unknown, non-baryonic form. This book first discusses the known forms, comets, planets, brown dwarfs, stars, gas, galaxies and Lyman α clouds in which baryons are known to exist. Limits on the amount of dark matter in baryonic form are discussed in the context of the big bang. Inhomogeneities of the right type alleviate the difficulties associated with Ω B = 1 cosmological nucleosynthesis

Meson-baryon coupling constants from a chiral-invariant SU(3) Lagrangian and application to NN scattering

International Nuclear Information System (INIS)

Stoks, V.G.J.

1997-01-01

We present a chiral-invariant meson-baryon Lagrangian which describes the interactions of the baryon octet with the lowest-mass meson nonets. The nonlinear realization of the chiral symmetry generates pair-meson interaction vertices. The corresponding pair-meson coupling constants can all be expressed in terms of the meson-nucleon-nucleon pseudovector, scalar, and vector coupling constants, and their corresponding F/(F+D) ratios, and for which empirical estimates are given. We show that it is possible to construct an NN potential of reasonable quality satisfying these theoretical and empirical constraints. (orig.)

Calculation of baryon sum rules and SU(4) mass formulae for mesons and baryons

International Nuclear Information System (INIS)

Bongardt, K.

1976-01-01

Light cone coordinates and field-field anticommutators for the free quark model on the light cone are introduced and light cone charges and light cone currents for the free quark model as well as sum rules for the meson and quark states are derived. The derivation of sum rules for the baryons is attempted. It is seen that it is possible formally to derive the same sum rules for the baryons and for the quarks. The baryon sums were derived through the symmetry properties of the baryon fields. Explicit assumptions about the spatial distribution of the three quarks in the baryons were not utilized. The meson-baryon Σ-terms, Zweig's rules in the SU (4) and a number of properties of the M-matrix are discussed. (BJ) [de

The link between the baryonic mass distribution and the rotation curve shape

Science.gov (United States)

Swaters, R. A.; Sancisi, R.; van der Hulst, J. M.; van Albada, T. S.

2012-09-01

The observed rotation curves of disc galaxies, ranging from late-type dwarf galaxies to early-type spirals, can be fitted remarkably well simply by scaling up the contributions of the stellar and H I discs. This 'baryonic scaling model' can explain the full breadth of observed rotation curves with only two free parameters. For a small fraction of galaxies, in particular early-type spiral galaxies, H I scaling appears to fail in the outer parts, possibly due to observational effects or ionization of H I. The overall success of the baryonic scaling model suggests that the well-known global coupling between the baryonic mass of a galaxy and its rotation velocity (known as the baryonic Tully-Fisher relation) applies at a more local level as well, and it seems to imply a link between the baryonic mass distribution and the distribution of total mass (including dark matter).

On determination of the charmed Λc+ baryon polarization

International Nuclear Information System (INIS)

Lednitski, R.

1986-01-01

Expressions have been obtained for angular distributions in various cascade decays of the Λ c + baryon, which make it possible to evaluate its polarization and the corresponding asymmetry parameters. Errors in these parameters are estimated. An importance of polarizational measurements for the study of quark interactions at ''large'' distances is indicated. The following conclusions are made: 1.Polarization measurement of Λ c + baryon P c and measurement of asymmetry parameters of its α c decays is of importance for determination of mechanisms of quark production and hadronization. In particular, difference of asymmetries of angular distributions of decay nucleons and Λ hyperons is a measure of contribution of non-spectrum diagrams, sensitive to quark interactions at large distances. 2.Since parameters of α c asymmetry are unknown it is possible to determine only the lowe boundary corresponding to α c =1 with the help of measurement of Λ c + baryon decay asymmetries. 3.Λ c + baryon polarization and asymmetry parameters can be determined with the help of analysis of angular distributions in its cascade decays under the condition that the asymmetry parameter or other odd multipole parameter characterizing secondary decay, is known before. For measurement of Λ c + baryon polarization its two-particle or quasi-two-particle decays are mostly efficient

Doubly heavy baryon production at γγ collider

International Nuclear Information System (INIS)

Li Shiyuan; Si Zongguo; Yang Zhongjuan

2007-01-01

The inclusive production of doubly heavy baryons Ξ cc and Ξ bb at γγ collider is investigated. It is found that the contribution from the heavy quark pair QQ in color triplet and color sextet are important

Baryonic Dark Matter

OpenAIRE

Silk, Joseph

1994-01-01

In the first two of these lectures, I present the evidence for baryonic dark matter and describe possible forms that it may take. The final lecture discusses formation of baryonic dark matter, and sets the cosmological context.

Meson-baryon components in the states of the baryon decuplet

Energy Technology Data Exchange (ETDEWEB)

Aceti, F.; Oset, E. [Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Departamento de Fisica Teorica y IFIC, Valencia (Spain); Kavli Institute for Theoretical Physics China, Beijing (China); Dai, L.R. [Liaoning Normal University, Department of Physics, Dalian (China); Kavli Institute for Theoretical Physics China, Beijing (China); Geng, L.S. [Beihang University, School of Physics and Nuclear Energy Engineering and International Research Center for Nuclei and Particles in the Cosmos, Beijing (China); Zhang, Y. [Liaoning Normal University, Department of Physics, Dalian (China)

2014-03-15

We apply an extension of the Weinberg compositeness condition on partial waves of L = 1 and resonant states to determine the weight of the meson-baryon component in the Δ(1232) resonance and the other members of the J{sup P} = (3)/(2){sup +} baryon decuplet. We obtain an appreciable weight of πN in the Δ(1232) wave function, of the order of 60%, which looks more natural when one recalls that experiments on deep inelastic and Drell Yan give a fraction of πN component of 34% for the nucleon. We also show that, as we go to higher energies in the members of the decuplet, the weights of the meson-baryon component decrease and they already show a dominant part for a genuine, non-meson-baryon, component in the wave function. We write a section to interpret the meaning of the Weinberg sum rule when it is extended to complex energies and another one for the case of an energy-dependent potential. (orig.)

BULK THERMODYNAMICS AND CHARGE FLUCTUATIONS AT NON-VANISHING BARYON DENSITY

International Nuclear Information System (INIS)

MIAO, C.; SCHMIDT, C.

2007-01-01

We present results on bulk thermodynamic quantities as well as net baryon number, strangeness and electric charge fluctuations in QCD at non-zero density and temperature obtained from lattice calculations with almost physical quark masses for two values of the lattice cut-off aT = 1/4 and 1/6. We show that with our improved p4fa3-action the cut-off effects are under control when using lattices with a temporal extent of 6 or larger and that the contribution to the equation of state, which is due to a finite chemical potential is small for μ q /T < 1. Moreover, at vanishing chemical potential, i.e. under conditions almost realized at RHIC and the LHC, quartic fluctuations of net baryon number and strangeness are large in a narrow temperature interval characterizing the transition region from the low to high temperature phase. At non-zero baryon number density, strangeness fluctuations are enhanced and correlated to fluctuations of the net baryon number. If strangeness is furthermore forced to vanish, as it may be the case in systems created in heavy ion collisions, strangeness fluctuations are significantly smaller than baryon number fluctuations

Baryons in the unquenched quark model

Energy Technology Data Exchange (ETDEWEB)

Bijker, R.; Díaz-Gómez, S. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, AP 70-543, 04510 Mexico DF (Mexico); Lopez-Ruiz, M. A. [Physics Department and Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN 47408 (United States); Santopinto, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Genova, via Dodecaneso 33, I-16146 Italy (Italy)

2016-07-07

In this contribution, we present the unquenched quark model as an extension of the constituent quark model that includes the effects of sea quarks via a {sup 3}P{sub 0} quark-antiquark pair-creation mechanism. Particular attention is paid to the spin and flavor content of the proton, magnetic moments and β decays of octet baryons.

Measuring baryon-(anti-)baryon interaction cross-sections with femtoscopy in Heavy-Ion Collisions

Energy Technology Data Exchange (ETDEWEB)

Kisiel, A.

2016-12-15

Two-particle correlations at low relative momentum (femtoscopy) are used to study the space-time dynamics of the source created in heavy-ion collisions. The same method can be used in a novel way to study the Final State Interaction potential for various particle pairs. The parameters are also directly related to the relevant interaction cross-sections. Of special interest are correlations of baryons, where the strong interaction often dominates. The femtoscopic technique offers a unique opportunity to study this interaction in such systems. In this work we discuss the similarities and differences of such measurement for baryon-baryon and baryon-antibaryon pairs.

The width of the Δ-resonance at two loop order in baryon chiral perturbation theory

Energy Technology Data Exchange (ETDEWEB)

Gegelia, Jambul, E-mail: j.gegelia@fz-juelich.de [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Tbilisi State University, 0186 Tbilisi, Georgia (United States); Meißner, Ulf-G., E-mail: meissner@hiskp.uni-bonn.de [Helmholtz Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Siemens, Dmitrij, E-mail: dmitrij.siemens@rub.de [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Yao, De-Liang, E-mail: d.yao@fz-juelich.de [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany)

2016-12-10

We calculate the width of the delta resonance at leading two-loop order in baryon chiral perturbation theory. This gives a correlation between the leading pion–nucleon–delta and pion–delta couplings, which is relevant for the analysis of pion–nucleon scattering and other processes.

Doubly heavy baryon production at {gamma}{gamma} collider

Energy Technology Data Exchange (ETDEWEB)

Li Shiyuan [Department of Physics, Shandong University, Jinan 250100 (China)]. E-mail: lishy@sdu.edu.cn; Si Zongguo [Department of Physics, Shandong University, Jinan 250100 (China)]. E-mail: zgsi@sdu.edu.cn; Yang Zhongjuan [Department of Physics, Shandong University, Jinan 250100 (China)]. E-mail: yangzhongjuan@mail.sdu.edu.cn

2007-05-10

The inclusive production of doubly heavy baryons {xi}{sub cc} and {xi}{sub bb} at {gamma}{gamma} collider is investigated. It is found that the contribution from the heavy quark pair QQ in color triplet and color sextet are important.

Search for a narrow baryonic state decaying to pKS0 and p‾KS0 in deep inelastic scattering at HERA

Directory of Open Access Journals (Sweden)

H. Abramowicz

2016-08-01

Full Text Available A search for a narrow baryonic state in the pKS0 and p‾KS0 system has been performed in ep collisions at HERA with the ZEUS detector using an integrated luminosity of 358pb−1 taken in 2003–2007. The search was performed with deep inelastic scattering events at an ep centre-of-mass energy of 318GeV for exchanged photon virtuality, Q2, between 20 and 100GeV2. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb−1 taken in 1996–2000, no resonance peak was found in the p(p‾KS0 invariant-mass distribution in the range 1.45–1.7 GeV. Upper limits on the production cross section are set.

Baryonic distributions in galaxy dark matter haloes - II. Final results

Science.gov (United States)

Richards, Emily E.; van Zee, L.; Barnes, K. L.; Staudaher, S.; Dale, D. A.; Braun, T. T.; Wavle, D. C.; Dalcanton, J. J.; Bullock, J. S.; Chandar, R.

2018-06-01

Re-creating the observed diversity in the organization of baryonic mass within dark matter haloes represents a key challenge for galaxy formation models. To address the growth of galaxy discs in dark matter haloes, we have constrained the distribution of baryonic and non-baryonic matter in a statistically representative sample of 44 nearby galaxies defined from the Extended Disk Galaxy Exploration Science (EDGES) Survey. The gravitational potentials of each galaxy are traced using rotation curves derived from new and archival radio synthesis observations of neutral hydrogen (H I). The measured rotation curves are decomposed into baryonic and dark matter halo components using 3.6 μm images for the stellar content, the H I observations for the atomic gas component, and, when available, CO data from the literature for the molecular gas component. The H I kinematics are supplemented with optical integral field spectroscopic (IFS) observations to measure the central ionized gas kinematics in 26 galaxies, including 13 galaxies that are presented for the first time in this paper. Distributions of baryonic-to-total mass ratios are determined from the rotation curve decompositions under different assumptions about the contribution of the stellar component and are compared to global and radial properties of the dominant stellar populations extracted from optical and near-infrared photometry. Galaxies are grouped into clusters of similar baryonic-to-total mass distributions to examine whether they also exhibit similar star and gas properties. The radial distribution of baryonic-to-total mass in a galaxy does not appear to correlate with any characteristics of its star formation history.

Baryons with chromodynamics

International Nuclear Information System (INIS)

Isgur, N.

1981-01-01

Many of the phenomenological difficulties of the non-relativistic quark model for baryons are overcome when some current prejudices from chromodynamics about quark forces are imposed. The effects of flavour independent confinement, symmetry breaking through quark masses, and colour hyperfine interactions are most prominent, leading to a satisfactory understanding of both the spectroscopy of low-lying baryons and of the signs and magnitudes of baryon couplings. The previously worrisome absence in partial wave analyses of a large number of the states expected in the nonrelativistic quark model is explained in terms of decouplings of the resonances from their elastic channels

Calm Multi-Baryon Operators

Directory of Open Access Journals (Sweden)

Berkowitz Evan

2018-01-01

Full Text Available There are many outstanding problems in nuclear physics which require input and guidance from lattice QCD calculations of few baryons systems. However, these calculations suffer from an exponentially bad signal-to-noise problem which has prevented a controlled extrapolation to the physical point. The variational method has been applied very successfully to two-meson systems, allowing for the extraction of the two-meson states very early in Euclidean time through the use of improved single hadron operators. The sheer numerical cost of using the same techniques in two-baryon systems has so far been prohibitive. We present an alternate strategy which offers some of the same advantages as the variational method while being significantly less numerically expensive. We first use the Matrix Prony method to form an optimal linear combination of single baryon interpolating fields generated from the same source and different sink interpolating fields. Very early in Euclidean time this optimal linear combination is numerically free of excited state contamination, so we coin it a calm baryon. This calm baryon operator is then used in the construction of the two-baryon correlation functions.To test this method, we perform calculations on the WM/JLab iso-clover gauge configurations at the SU(3 flavor symmetric point with mπ~ 800 MeV — the same configurations we have previously used for the calculation of two-nucleon correlation functions. We observe the calm baryon significantly removes the excited state contamination from the two-nucleon correlation function to as early a time as the single-nucleon is improved, provided non-local (displaced nucleon sources are used. For the local two-nucleon correlation function (where both nucleons are created from the same space-time location there is still improvement, but there is significant excited state contamination in the region the single calm baryon displays no excited state contamination.

Isospin breaking in the pion-nucleon scattering lengths

International Nuclear Information System (INIS)

Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.

2009-01-01

We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.

Isospin breaking in the pion-nucleon scattering lengths

Energy Technology Data Exchange (ETDEWEB)

Hoferichter, Martin [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany)], E-mail: kubis@itkp.uni-bonn.de; Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (Theorie), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)

2009-07-06

We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.

Baryon chiral perturbation theory extended beyond the low-energy region.

Science.gov (United States)

Epelbaum, E; Gegelia, J; Meißner, Ulf-G; Yao, De-Liang

We consider an extension of the one-nucleon sector of baryon chiral perturbation theory beyond the low-energy region. The applicability of this approach for higher energies is restricted to small scattering angles, i.e. the kinematical region, where the quark structure of hadrons cannot be resolved. The main idea is to re-arrange the low-energy effective Lagrangian according to a new power counting and to exploit the freedom of the choice of the renormalization condition for loop diagrams. We generalize the extended on-mass-shell scheme for the one-nucleon sector of baryon chiral perturbation theory by choosing a sliding scale, that is, we expand the physical amplitudes around kinematical points beyond the threshold. This requires the introduction of complex-valued renormalized coupling constants, which can be either extracted from experimental data, or calculated using the renormalization group evolution of coupling constants fixed in threshold region.

Baryon chiral perturbation theory extended beyond the low-energy region

International Nuclear Information System (INIS)

Epelbaum, E.; Gegelia, J.; Meissner, Ulf G.; Yao, De-Liang

2015-01-01

We consider an extension of the one-nucleon sector of baryon chiral perturbation theory beyond the low-energy region. The applicability of this approach for higher energies is restricted to small scattering angles, i.e. the kinematical region, where the quark structure of hadrons cannot be resolved. The main idea is to re-arrange the low-energy effective Lagrangian according to a new power counting and to exploit the freedom of the choice of the renormalization condition for loop diagrams. We generalize the extended on-mass-shell scheme for the one-nucleon sector of baryon chiral perturbation theory by choosing a sliding scale, that is, we expand the physical amplitudes around kinematical points beyond the threshold. This requires the introduction of complex-valued renormalized coupling constants, which can be either extracted from experimental data, or calculated using the renormalization group evolution of coupling constants fixed in threshold region. (orig.)

Modified skyrmion in a baryonic matter

International Nuclear Information System (INIS)

Mishustin, I.N.

1990-01-01

A unified field model describing individual baryons and baryonic matter is developed. The model is based on a chiral-symmetry Lagrangian including the scalar, pion and vector fields interacting with the scalar density and the 4-current of baryons (linear σ-model supplemented by a vector field). Essentially inhomogeneous soliton solutions of the topological type (skirmions) correspond to the individual baryons, whereas homogeneous field configurations correspond to baryonic matter. Estimations show that the model predicts a correct scale of changes of the effective mass (15%) and the radius for the baryon for a normal nuclear matter density. For high baryon densities the model with a massive vector field predicts a phase transition which results in the restoration of chiral symmetry. The new state of the system is characterized by a homogeneous distribution of the meson fields and energy

Strangeness S = -2 baryon-baryon interactions using chiral effective field theory

NARCIS (Netherlands)

Polinder, H.; Haidenbauer, J.; Meissner, U.G.

2007-01-01

We derive the leading order strangeness S =−2 baryon–baryon interactions in chiral effective field theory. The potential consists of contact terms without derivatives and of one-pseudoscalar-meson exchanges. The contact terms and the couplings of the pseudoscalar mesons to the baryons are related

Baryon mass splittings in chiral perturbation theory

International Nuclear Information System (INIS)

Banerjee, M.K.; Milana, J.

1995-01-01

Baryon masses are calculated in chiral perturbation theory at the one-loop O(p 3 ) level in chiral expansion and to leading order in the heavy baryon expansion. Ultraviolet divergences occur requiring the introduction of counterterms. Despite this necessity, no knowledge of the counterterms is required to determine the violations of the Gell-Mann--Okubo mass relation for the baryon octet or of the decuplet equal-mass-spacing rule, as all divergences cancel exactly at this order. For the same reason all references to an arbitrary scale μ are absent. Neither of these features continue to higher powers in the chiral expansion. We also discuss critically the absolute necessity of simultaneously going beyond the leading-order heavy baryon expansion, if one goes beyond the one-loop O(p 3 ) level. We point out that these corrections in 1/M B generate new divergences ∝m 4 /M 10 . These divergences together with the divergences occurring in one-loop O(p 4 ) graphs of chiral perturbation theory are taken care of by the same set of counterterms. Because of these unknown counterterms one cannot predict the baryon mass splittings at the one-loop O(p 4 ) level even if the parameters of all scrL 1 πN terms are known. We point out another serious problem of going to the one-loop O(p 4 ) level. When the decuplet is off its mass shell there are additional πNΔ and πΔΔ interaction terms. These interactions contribute to the divergent terms ∝(m 4 /M 10 ), and also to nonanalytic terms such as ∝(m 4 /M 10 )ln(m/M 10 ). Without knowledge of the coupling constants appearing in these interactions, one cannot carry out a consistent one-loop O(p 4 ) level calculation

Meson and baryon production in K/sup +/ and. pi. /sup +/ beam jets and quark-diquark cascade model

Energy Technology Data Exchange (ETDEWEB)

Kinoshita, Kisei [Kagoshima Univ. (Japan). Faculty of Education; Noda, Hujio; Tashiro, Tsutomu

1982-11-01

A quark-diquark cascade model which includes flavor dependence and resonance effect is studied. The inclusive distributions of vector and pseudoscalar mesons and octet baryons and antibaryons in K/sup +/ and ..pi../sup +/ beam jets are analyzed. The contribution of decuplet baryons to the octet baryon spectra is very important in meson beam jet. The effects of the asymmetric u- and anti s-quark distributions in K/sup +/ and the SU(6)-symmetry breaking for the produced octet baryon are discussed in connection with the ..pi../sup +//K/sup +/ beam ratio and other data.

Generalized polarizabilities of the nucleon in baryon chiral perturbation theory

Energy Technology Data Exchange (ETDEWEB)

Lensky, Vadim [Johannes Gutenberg Universitaet Mainz, Institut fuer Kernphysik, Cluster of Excellence PRISMA, Mainz (Germany); Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Pascalutsa, Vladimir; Vanderhaeghen, Marc [Johannes Gutenberg Universitaet Mainz, Institut fuer Kernphysik, Cluster of Excellence PRISMA, Mainz (Germany)

2017-02-15

The nucleon generalized polarizabilities (GPs), probed in virtual Compton scattering (VCS), describe the spatial distribution of the polarization density in a nucleon. They are accessed experimentally via the process of electron-proton bremsstrahlung (ep → epγ) at electron-beam facilities, such as MIT-Bates, CEBAF (Jefferson Lab), and MAMI (Mainz). We present the calculation of the nucleon GPs and VCS observables at next-to-leading order in baryon chiral perturbation theory (BχPT), and confront the results with the empirical information. At this order our results are predictions, in the sense that all the parameters are well known from elsewhere. Within the relatively large uncertainties of our calculation we find good agreement with the experimental observations of VCS and the empirical extractions of the GPs. We find large discrepancies with previous chiral calculations - all done in heavy-baryon χPT (HBχPT) - and discuss the differences between BχPT and HBχPT responsible for these discrepancies. (orig.)

Baryonic matter and beyond

OpenAIRE

Fukushima, Kenji

2014-01-01

We summarize recent developments in identifying the ground state of dense baryonic matter and beyond. The topics include deconfinement from baryonic matter to quark matter, a diquark mixture, topological effect coupled with chirality and density, and inhomogeneous chiral condensates.

Baryon-baryon bound states from first principles in 3+1 lattice QCD with two flavors and strong coupling

International Nuclear Information System (INIS)

Faria da Veiga, Paulo A.; O'Carroll, Michael

2006-01-01

We determine baryon-baryon bound states in (3+1)-dimensional SU(3) lattice QCD with two flavors, 4x4 spin matrices, and in an imaginary time formulation. For small hopping parameter κ>0 and large glueball mass (strong coupling), we show the existence of three-quark isospin 1/2 particles (proton and neutron) and isospin 3/2 baryons (delta particles), with asymptotic masses -3lnκ and isolated dispersion curves. Baryon-baryon bound states of isospin zero are found with binding energy of order κ 2 , using a ladder approximation to a lattice Bethe-Salpeter equation. The dominant baryon-baryon interaction is an energy-independent spatial range-one attractive potential with an O(κ 2 ) strength. There is also attraction arising from gauge field correlations associated with six overlapping bonds, but it is counterbalanced by Pauli repulsion to give a vanishing zero-range potential. The overall range-one potential results from a quark, antiquark exchange with no meson exchange interpretation; the repulsive or attractive nature of the interaction depends on the isospin and spin of the two-baryon state

Center-vortex baryonic area law

International Nuclear Information System (INIS)

Cornwall, John M.

2004-01-01

We correct an unfortunate error in an earlier work of the author, and show that in the center-vortex picture of QCD [gauge group SU(3)] the asymptotic quenched baryonic area law is the so-called Y law, described by a minimal area with three surfaces spanning the three quark world lines and meeting at a central Steiner line joining the two common meeting points of the world lines. (The earlier claim was that this area law was a so-called Δ law, involving three extremal areas spanning the three pairs of quark world lines.) By asymptotic we mean the Y law holds at asymptotically large quark separations from each other; at separations of the order of the gauge-theory scale length, there may be Δ-like contributions. We give a preliminary discussion of the extension of these results to SU(N),N>3. These results are based on the (correct) baryonic Stokes' theorem given in the earlier work claiming a Δ law. The Y-form area law for SU(3) is in agreement with the most recent lattice calculations

Flux-ratio anomalies from discs and other baryonic structures in the Illustris simulation

Science.gov (United States)

Hsueh, Jen-Wei; Despali, Giulia; Vegetti, Simona; Xu, Dandan; Fassnacht, Christopher D.; Metcalf, R. Benton

2018-04-01

The flux ratios in the multiple images of gravitationally lensed quasars can provide evidence for dark matter substructure in the halo of the lensing galaxy if the flux ratios differ from those predicted by a smooth model of the lensing galaxy mass distribution. However, it is also possible that baryonic structures in the lensing galaxy, such as edge-on discs, can produce flux-ratio anomalies. In this work, we present the first statistical analysis of flux-ratio anomalies due to baryons from a numerical simulation perspective. We select galaxies with various morphological types in the Illustris simulation and ray trace through the simulated haloes, which include baryons in the main lensing galaxies but exclude any substructures, in order to explore the pure baryonic effects. Our ray-tracing results show that the baryonic components can be a major contribution to the flux-ratio anomalies in lensed quasars and that edge-on disc lenses induce the strongest anomalies. We find that the baryonic components increase the probability of finding high flux-ratio anomalies in the early-type lenses by about 8 per cent and by about 10-20 per cent in the disc lenses. The baryonic effects also induce astrometric anomalies in 13 per cent of the mock lenses. Our results indicate that the morphology of the lens galaxy becomes important in the analysis of flux-ratio anomalies when considering the effect of baryons, and that the presence of baryons may also partially explain the discrepancy between the observed (high) anomaly frequency and what is expected due to the presence of subhaloes as predicted by the cold dark matter simulations.

Modeling the Impact of Baryons on Subhalo Populations with Machine Learning

Science.gov (United States)

Nadler, Ethan O.; Mao, Yao-Yuan; Wechsler, Risa H.; Garrison-Kimmel, Shea; Wetzel, Andrew

2018-06-01

We identify subhalos in dark matter–only (DMO) zoom-in simulations that are likely to be disrupted due to baryonic effects by using a random forest classifier trained on two hydrodynamic simulations of Milky Way (MW)–mass host halos from the Latte suite of the Feedback in Realistic Environments (FIRE) project. We train our classifier using five properties of each disrupted and surviving subhalo: pericentric distance and scale factor at first pericentric passage after accretion and scale factor, virial mass, and maximum circular velocity at accretion. Our five-property classifier identifies disrupted subhalos in the FIRE simulations with an 85% out-of-bag classification score. We predict surviving subhalo populations in DMO simulations of the FIRE host halos, finding excellent agreement with the hydrodynamic results; in particular, our classifier outperforms DMO zoom-in simulations that include the gravitational potential of the central galactic disk in each hydrodynamic simulation, indicating that it captures both the dynamical effects of a central disk and additional baryonic physics. We also predict surviving subhalo populations for a suite of DMO zoom-in simulations of MW-mass host halos, finding that baryons impact each system consistently and that the predicted amount of subhalo disruption is larger than the host-to-host scatter among the subhalo populations. Although the small size and specific baryonic physics prescription of our training set limits the generality of our results, our work suggests that machine-learning classification algorithms trained on hydrodynamic zoom-in simulations can efficiently predict realistic subhalo populations.

Practical way to avoid spurious geometrical contributions in Brillouin light scattering experiments at variable scattering angles.

Science.gov (United States)

Battistoni, Andrea; Bencivenga, Filippo; Fioretto, Daniele; Masciovecchio, Claudio

2014-10-15

In this Letter, we present a simple method to avoid the well-known spurious contributions in the Brillouin light scattering (BLS) spectrum arising from the finite aperture of collection optics. The method relies on the use of special spatial filters able to select the scattered light with arbitrary precision around a given value of the momentum transfer (Q). We demonstrate the effectiveness of such filters by analyzing the BLS spectra of a reference sample as a function of scattering angle. This practical and inexpensive method could be an extremely useful tool to fully exploit the potentiality of Brillouin acoustic spectroscopy, as it will easily allow for effective Q-variable experiments with unparalleled luminosity and resolution.

Flavour and spin structure of linear baryons

International Nuclear Information System (INIS)

Kawarabayashi, K.; Kitakado, S.; Inami, T.

1979-01-01

Based on the string picture, a phenomenological model for baryons is constructed and their flavour symmetry, exchange degeneracy pattern and spin structure are studied. Baryons on leading trajectories are assumed to have the configuration of two quarks being attached to the ends of a linear string and the third sitting in the middle, called linear baryons. For such linear baryons, a unitarization scheme can be constructed in a manner similar to the dual unitarity scheme for mesons but without recourse to the 1/N expansion. It is found that the interchange interaction of the middle quark with one of the other two quarks at the ends of the string can give rise to a larger exchange degeneracy breaking of the baryon spectrum. With this non-planar correction, the model of linear baryons can account for the observed pattern of leading baryon states. (Auth.)

Baryon-Baryon Interactions ---Nijmegen Extended-Soft-Core Models---

Science.gov (United States)

Rijken, T. A.; Nagels, M. M.; Yamamoto, Y.

pseudo-scalar-, vector-, scalar-, and axial-mesons, (ii) diffractive (i.e. multiple-gluon) exchanges, (iii) two pseudo-scalar exchange (PS-PS), and (iv) meson-pair-exchange (MPE). The OBE- and pair-vertices are regulated by gaussian form factors producing potentials with a soft behavior near the origin. The assignment of the cutoff masses for the BBM-vertices is dependent on the SU(3)-classification of the exchanged mesons for OBE, and a similar scheme for MPE. The ESC-models ESC04 and ESC08 describe the nucleon-nucleon (NN), hyperon-nucleon (YN), and hyperon-hyperon (YY) interactions in a unified way using broken SU(3)-symmetry. Novel ingredients in the OBE-sector in the ESC-models are the inclusion of (i) the axial-vector meson potentials, (ii) a zero in the scalar- and axial-vector meson form factors. These innovations made it possible for the first time to keep the meson coupling parameters of the model qualitatively in accordance with the predictions of the (3P_0) quark-antiquark creation (QPC) model. This is also the case for the F/(F+D)-ratios. Furthermore, the introduction of the zero helped to avoid the occurrence of unwanted bound states in Lambda N. Broken SU(3)-symmetry serves to connect the NN and the YN channels, which leaves after fitting NN only a few free parameters for the determination of the YN-interactions. In particular, the meson-baryon coupling constants are calculated via SU(3) using the coupling constants of the NN oplus YN-analysis as input. In ESC04 medium strong flavor-symmetry-breaking (FSB) of the coupling constants was investigated, using the (3}P_{0) -model with a Gell-Mann-Okubo hypercharge breaking for the BBM-coupling. In ESC08 the couplings are kept SU(3)-symmetric. The charge-symmetry-breaking (CSB) in the Lambda p and Lambda n channels, which is an SU(2) isospin breaking, is included in the OBE-, TME-, and MPE-potentials. In ESC04 and ESC08 simultaneous fits to the NN- and the YN- scattering data have been achieved, using different

Investigation of the source size and strong interaction with the femtoscopic correlations of baryons and antibaryons in heavy-ion collisions registered by ALICE

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00508100

The strong interaction is one of the four fundamental forces of nature. It binds together quarks inside protons and neutrons (which are example of baryons - particles composed of three quarks) and assures the stability of the atomic nucleus. Parameters describing the strong potential are also crucial for the neutron stars models used in astrophysics. What is more, a precise study of strongly interacting particles may help to better understand the process of baryon annihilation. The current knowledge of the strong interactions between baryons other than nucle- ons is limited - there exist only a few measurements of the cross sections for pairs of (anti)baryons. The reason is that in many cases it is not possible to perform scattering experiments with beams of particles and antiparticles, as the exotic matter (such as Λ, Ξ or Σ baryons) is very shot-living. This issue can be solved thanks to the recent particle colliders like the Large Hadron Collider and experiments dedicated to study the heavy-ion collisio...

Contribution of the Electron Scattering Process to the Broad Hα Wings

Directory of Open Access Journals (Sweden)

Sekeráš M.

2012-06-01

Full Text Available We modeled the extended wings of the OVI 1032, 1038 Å resonance lines and He II 1640 Å emission line in the spectra of Z And, AG Dra and V1016 Cyg by the electron scattering process. By this way we determined the electron temperature and the electron optical depth of the layer of electrons, through which the line photons are transferred in the direction of the observer. We derived an empirical relationship between the emission measure of the symbiotic nebula and the electron optical depth. This relationship allows us to distinguish the flux contribution in the broad Hα wings, which is due to the electron scattering and that produced by the Hα transition in the moving hydrogen plasma. For example, subtracting the electron scattering contribution from the Hα line profile leads to a reduction in the mass-loss rate by approximately 15 %.

B decays to baryons

Indian Academy of Sciences (India)

We note that two-body decays to baryons are suppressed relative to three- and four-body decays. In most of these analyses, the invariant baryon–antibaryon mass shows an enhancement near the threshold. We propose a phenomenological interpretation of this quite common feature of hadronization to baryons.

Fermionic NNLO contributions to Bhabha scattering

International Nuclear Information System (INIS)

Actis, S.; Riemann, T.; Czakon, M.; Uniwersytet Slaski, Katowice; Gluza, J.

2007-10-01

We derive the two-loop corrections to Bhabha scattering from heavy fermions using dispersion relations. The double-box contributions are expressed by three kernel functions. Convoluting the perturbative kernels with fermionic threshold functions or with hadronic data allows to determine numerical results for small electron mass m e , combined with arbitrary values of the fermion mass m f in the loop, m 2 e 2 f , or with hadronic insertions. We present numerical results for m f =m μ , m τ ,m top at typical small- and large-angle kinematics ranging from 1 GeV to 500 GeV. (orig.)

Outlook for baryon spectroscopy

International Nuclear Information System (INIS)

Tripp, R.D.

1976-09-01

The review of baryon spectroscopy includes a number of new generation experiments with greatly improved statistics which have emerged and are enhancing experimental knowledge of baryon resonances. The future research directions are pointed out, and some problems and deficiencies which can be resolved with contemporary techniques are mentioned

Baryon number violation and string topologies

International Nuclear Information System (INIS)

Sjoestrand, T.; Skands, P.Z.

2003-01-01

In supersymmetric scenarios with broken R-parity, baryon number violating sparticle decays become possible. In order to search for such decays, a good understanding of expected event properties is essential. We here develop a complete framework that allows detailed studies. Special attention is given to the hadronization phase, wherein the baryon number violating vertex is associated with the appearance of a junction in the colour confinement field. This allows us to tell where to look for the extra (anti)baryon directly associated with the baryon number violating decay

Diquark structure of baryons

International Nuclear Information System (INIS)

Silvestre-Brac, B.

1987-01-01

Three body calculations for studying the baryons are performed in a non-relativistic treatment with three quarks interacting via Bhaduri's potential. From the resulting wave functions, it is analysed under which conditions can a diquark structure occurs. Several photos showing quark distributions inside the baryons are presented and discussed in details

Measurement of the masses and widths of the bottom baryons Σ.sup.+-./sup..sub. b./sub. and Σ.sup.*+−./sup. .sub. b./sub..

Czech Academy of Sciences Publication Activity Database

Aaltonen, T.; Gonzalez, B.A.; Amerio, S.; Lysák, Roman

2012-01-01

Roč. 85, č. 9 (2012), "092011-1"-"092011-13" ISSN 1550-7998 R&D Projects: GA MŠk LC527 Institutional research plan: CEZ:AV0Z10100502 Keywords : bottom baryon mass * bottom baryon track data analysis: vertex * anti-p p scattering * TEVATRON Coll * CDF Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.691, year: 2012 http://link.aps.org/doi/10.1103/PhysRevD.85.092011

Vorticity and Λ polarization in baryon rich matter

Science.gov (United States)

Baznat, Mircea; Gudima, Konstantin; Prokhorov, George; Sorin, Alexander; Teryaev, Oleg; Zakharov, Valentin

2018-02-01

The polarization of Λ hyperons due to axial chiral vortical effect is discussed. The effect is proportional to (strange) chemical potential and is pronounced at lower energies in baryon-rich matter. The polarization of ¯ has the same sihn and larger magnitude. The emergence of vortical structures is observed in kinetic QGSM models. The hydrodynamical helicity separation receives the contribution of longitudinal velocity and vorticity implying the quadrupole structure of the latter. The transition from the quark vortical effects to baryons in confined phase may be achieved by exploring the axial charge. At the hadronic level the polarization corresponds to the cores of quantized vortices in pionic superfluid. The chiral vortical effects may be also studied in the frmework of Wigner function establishing the relation to the thermodynamical approach to polarization.

The pion contribution to semi-inclusive deep inelastic scattering with slow baryons in the final state

NARCIS (Netherlands)

Korpa, C. L.; Dieperink, A. E. L.; Scholten, O.

1992-01-01

We analyze the pion-exchange contribution to semi-inclusive leptoproduction on protons, with a slow nucleon or delta in the final state. We calculate the crosssection for slow protons including also the effect of the delta intermediate state, which is the dominant contribution. A comparison with

Self-energies of octet and decuplet baryons due to the coupling to the baryon-meson continuum

Energy Technology Data Exchange (ETDEWEB)

Garcia-Tecocoatzi, H. [INFN, Sezione di Genova, Genova (Italy); Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico (Mexico); Bijker, R. [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico (Mexico); Ferretti, J. [Chinese Academy of Sciences, Institute of Theoretical Physics, Beijing (China); Dipartimento di Fisica, Universita di Roma Sapienza, Roma (Italy); INFN, Roma (Italy); Santopinto, E. [INFN, Sezione di Genova, Genova (Italy)

2017-06-15

We present an unquenched quark model calculation of the mass shifts of ground-state octet and decuplet baryons due to the coupling to the meson-baryon continuum. All ground-state baryons and pseudoscalar mesons are included in our calculation as intermediate states. The q anti q pair creation effects are taken explicitly into account through a microscopic, QCD-inspired, quark-antiquark pair creation mechanism. (orig.)

Contribution of double scattering to structural coloration in quasiordered nanostructures of bird feathers

Science.gov (United States)

Noh, Heeso; Liew, Seng Fatt; Saranathan, Vinodkumar; Prum, Richard O.; Mochrie, Simon G. J.; Dufresne, Eric R.; Cao, Hui

2010-05-01

We measured the polarization- and angle-resolved optical scattering and reflection spectra of the quasiordered nanostructures in the bird feather barbs. In addition to the primary peak that originates from single scattering, we observed a secondary peak which exhibits depolarization and distinct angular dispersion. We explained the secondary peak in terms of double scattering, i.e., light is scattered successively twice by the structure. The two sequential single-scattering events are considered uncorrelated. Using the Fourier power spectra of the nanostructures obtained from the small-angle x-ray scattering experiment, we calculated the double scattering of light in various directions. The double-scattering spectrum is broader than the single-scattering spectrum, and it splits into two subpeaks at larger scattering angle. The good agreement between the simulation results and the experimental data confirms that double scattering of light makes a significant contribution to the structural color.

Contribution of double scattering to structural coloration in quasiordered nanostructures of bird feathers

Energy Technology Data Exchange (ETDEWEB)

Noh, Heeso; Liew, Seng Fatt; Saranathan, Vinodkumar; Prum, Richard O.; Mochrie, Simon G.J.; Dufresne, Eric R.; Cao, Hui (Yale)

2010-07-28

We measured the polarization- and angle-resolved optical scattering and reflection spectra of the quasiordered nanostructures in the bird feather barbs. In addition to the primary peak that originates from single scattering, we observed a secondary peak which exhibits depolarization and distinct angular dispersion. We explained the secondary peak in terms of double scattering, i.e., light is scattered successively twice by the structure. The two sequential single-scattering events are considered uncorrelated. Using the Fourier power spectra of the nanostructures obtained from the small-angle x-ray scattering experiment, we calculated the double scattering of light in various directions. The double-scattering spectrum is broader than the single-scattering spectrum, and it splits into two subpeaks at larger scattering angle. The good agreement between the simulation results and the experimental data confirms that double scattering of light makes a significant contribution to the structural color.

Search for diquark clustering in baryons

International Nuclear Information System (INIS)

Fleck, S.; Silvestre-Brac, B.; Richard, J.M.

1988-03-01

In the framework of the non-relativistic quark model, we examine to which extent baryons consist of a quark bound to a localized cluster of two quarks simulating a diquark. We consider ground states and orbital excitations for various flavour combinations. A striking clustering shows up sometimes especially for the leading Regge trajectory of the nucleon and single flavoured baryons or for the ground state of baryons bearing two heavy flavours. This is, however, far from being a general pattern and there are clear differences between the three-quark description of baryons and the quark-diquark model

Search for a narrow baryonic state decaying to ${pK^0_S}$ and ${\\overline{p}K^0_S}$ in deep inelastic scattering at HERA

CERN Document Server

Abramowicz, H.; Adamczyk, L.; Adamus, M.; Antonelli, S.; Aushev, V.; Behnke, O.; Behrens, U.; Bertolin, A.; Bhadra, S.; Bloch, I.; Boos, E.G.; Brock, I.; Brook, N.H.; Brugnera, R.; Bruni, A.; Bussey, P.J.; Caldwell, A.; Capua, M.; Catterall, C.D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A.M.; Corradi, M.; Dementiev, R.K.; Devenish, RCE; Dusini, S.; Foster, B.; Gach, G; Gallo, E.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L.K.; Golubkov, Yu.A.; Grzelak, G.; Guzik, M.; Gwenlan, C.; Hain, W.; Hlushchenko, O.; Hochman, D.; Hori, R.; Ibrahim, Z.A.; Iga, Y.; Ishitsuka, M.; Januschek, F.; Jomhari, N.Z.; Kadenko, I.; Kananov, S.; Karshon, U.; Kaur, P.; Kisielewska, D.; Klanner, R.; Klein, U.; Korzhavina, I.A.; Kotański, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Krupa, B.; Kuprash, O.; Kuze, M; Levchenko, B.B.; Levy, A.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O.Yu.; Makarenko, I.; Malka, J.; Mastroberardino, A.; Mohamad Idris, F.; Mohammad Nasir, N; Myronenko, V.; Nagano, K.; Nobe, T.; Nowak, R.J.; Onishchuk, Yu.; Paul, E.; Perlański, W.; Pokrovskiy, N.S.; Polini, A.; Przybycien, M.; Roloff, P.; Ruspa, M.; Saxon, D.H.; Schioppa, M.; Schneekloth, U.; Schörner-Sadenius, T.; Shcheglova, L.M.; Shevchenko, R.; Shkola, O.; Shyrma, Yu.; Singh, I.; Skillicorn, I.O.; Słomiński, W.; Solano, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stopa, P.; Sztuk-Dambietz, J.; Tassi, E.; Tokushuku, K.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Wan Abdullah, W.A.T.; Wichmann, K.; Wing, M.; Yamada, S.; Yamazaki, Y.; Zakharchuk, N.; Żarnecki, A.F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B.O.; Zotkin, D.S.; Mastroberardino, A

2016-08-10

A search for a narrow baryonic state in the $pK^0_S$ and $\\overline{p}K^0_S$ system has been performed in $ep$ collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb$^{-1}$ taken in 2003-2007. The search was performed with deep inelastic scattering events at an $ep$ centre-of-mass energy of 318 GeV for exchanged photon virtuality, $Q^2$, between 20 and 100 $\\rm{} GeV^{2}$. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb$^{-1}$ taken in 1996-2000, no resonance peak was found in the $p(\\overline{p})K^0_S$ invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.

Search for a narrow baryonic state decaying to pK0S and anti pK0S in deep inelastic scattering at HERA

International Nuclear Information System (INIS)

Abramowicz, H.; Abt, I.; Adamczyk, L.

2016-06-01

A search for a narrow baryonic state in the pK 0 S and anti pK 0 S system has been performed in ep collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb -1 taken in 2003-2007. The search was performed with deep inelastic scattering events at an ep centre-of-mass energy of 318 GeV for exchanged photon virtuality, Q 2 , between 20 and 100 GeV 2 . Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb -1 taken in 1996-2000, no resonance peak was found in the p(anti p)K 0 S invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.

Baryons in the heavy quark effective theory

International Nuclear Information System (INIS)

Mannel, T.; Roberts, W.; Ryzak, Z.

1990-08-01

We show how to incorporate baryons in the heavy quark effective theory. A convenient formalism is exhibited and applied to semileptonic weak decays of heavy baryons and to exclusive production of heavy baryons in e + e - annihilation. (orig.)

Radiative decays of single heavy flavour baryons

International Nuclear Information System (INIS)

Majethiya, Ajay; Patel, Bhavin; Vinodkumar, P.C.

2009-01-01

The electromagnetic transitions between (J P =(3)/(2) + ) and (J P =(1)/(2) + ) baryons are important decay modes to observe new hadronic states experimentally. For the estimation of these transitions widths, we employ a non-relativistic quark potential model description with color Coulomb plus linear confinement potential. Such a description has been employed to compute the ground-state masses and magnetic moments of the single heavy flavor baryons. The magnetic moments of the baryons are obtained using the spin-flavor structure of the constituting quark composition of the baryon. Here, we also define an effective constituent mass of the quarks (ecqm) by taking into account the binding effects of the quarks within the baryon. The radiative transition widths are computed in terms of the magnetic moments of the baryon and the photon energy. Our results are compared with other theoretical models. (orig.)

Baryonic spectroscopy and its immediate future

International Nuclear Information System (INIS)

Dalitz, R.H.

1975-01-01

The quark model is reviewed briefly for baryons and the various versions of SU(6) symmetry which were proposed and used in connection with baryon spectroscopy are reviewed. A series of basic questions are reviewed which experimental work in this field should aim to settle, as a minimal program. One also heralds the beginning of a new baryon spectroscopy associated with psi physics

Magnetic moments of the lowest-lying singly heavy baryons

Science.gov (United States)

Yang, Ghil-Seok; Kim, Hyun-Chul

2018-06-01

A light baryon is viewed as Nc valence quarks bound by meson mean fields in the large Nc limit. In much the same way a singly heavy baryon is regarded as Nc - 1 valence quarks bound by the same mean fields, which makes it possible to use the properties of light baryons to investigate those of the heavy baryons. A heavy quark being regarded as a static color source in the limit of the infinitely heavy quark mass, the magnetic moments of the heavy baryon are determined entirely by the chiral soliton consisting of a light-quark pair. The magnetic moments of the baryon sextet are obtained by using the parameters fixed in the light-baryon sector. In this mean-field approach, the numerical results of the magnetic moments of the baryon sextet with spin 3/2 are just 3/2 larger than those with spin 1/2. The magnetic moments of the bottom baryons are the same as those of the corresponding charmed baryons.

Random walk of the baryon number

International Nuclear Information System (INIS)

Kazaryan, A.M.; Khlebnikov, S.Y.; Shaposhnikov, M.E.

1989-01-01

A new approach is suggested for the anomalous nonconservation of baryon number in the electroweak theory at high temperatures. Arguments are presented in support of the idea that the baryon-number changing reactions may be viewed as random Markov processes. Making use of the general theory of Markov processes, the Fokker--Planck equation for the baryon-number distribution density is obtained and kinetic coefficients are calculated

Semileptonic decays of Λ{sub c} baryons in the relativistic quark model

Energy Technology Data Exchange (ETDEWEB)

Faustov, R.N.; Galkin, V.O. [Institute of Informatics in Education, FRC CSC RAS, Moscow (Russian Federation)

2016-11-15

Motivated by recent experimental progress in studying weak decays of the Λ{sub c} baryon we investigate its semileptonic decays in the framework of the relativistic quark model based on the quasipotential approach with the QCD-motivated potential. The form factors of the Λ{sub c} → Λlν{sub l} and Λ{sub c} → nlν{sub l} decays are calculated in the whole accessible kinematical region without extrapolations and additional model assumptions. Relativistic effects are systematically taken into account including transformations of baryon wave functions from the rest to moving reference frame and contributions of the intermediate negative-energy states. Baryon wave functions found in the previous mass spectrum calculations are used for the numerical evaluation. Comprehensive predictions for decay rates, asymmetries and polarization parameters are given. They agree well with available experimental data. (orig.)

Search for Popcorn Mesons in Events with Two Charmed Baryons

Energy Technology Data Exchange (ETDEWEB)

Hartfiel, Brandon; /SLAC

2006-07-07

The physics of this note is divided into two parts. The first part measures the {Lambda}{sub c} {yields} {pi}kp continuum momentum spectrum at a center of mass energy of 10.54 GeV/c. The data sample consists of 15,400 {Lambda}{sub c} baryons from 9.46 fb{sup -1} of integrated luminosity. With more than 13 times more data than the best previous measurement, we are able to exclude some of the simpler, one parameter fragmentation functions. In the second part, we add the {Lambda}{sub c} {yields} K{sup 0}p mode, and look for events with a {Lambda}{sub c}{sup +} and a {bar {Lambda}}{sub c}{sup -} in order to look for ''popcorn'' mesons formed between the baryon and antibaryon. We add on-resonance data, with a kinematic cut to eliminate background from B decays, as well as BaBar run 3 and 4 data to increase the total data size to 219.70 fb{sup -1}. We find 619 events after background subtraction. After a subtraction of 1.06 {+-} .09 charged pions coming from decays of known resonances to {Lambda}{sub c} + {eta}{pi}, we are left with 2.63 {+-} .21 additional charged pions in each of these events. This is significantly higher than the .5 popcorn mesons per baryon pair used in the current tuning of Pythia 6.2, the most widely used Monte Carlo generator. The extra mesons we find appear to be the first direct evidence of popcorn mesons, although some of them could be arising from hypothetical unresolved, unobserved charmed baryon resonances contributing decay mesons to our data. To contribute a significant fraction, this hypothesis requires a large number of such broad unresolved states and seems unlikely, but can not be completely excluded.

Achieving maximum baryon densities

International Nuclear Information System (INIS)

Gyulassy, M.

1984-01-01

In continuing work on nuclear stopping power in the energy range E/sub lab/ approx. 10 GeV/nucleon, calculations were made of the energy and baryon densities that could be achieved in uranium-uranium collisions. Results are shown. The energy density reached could exceed 2 GeV/fm 3 and baryon densities could reach as high as ten times normal nuclear densities

Contribution of back-scattered electromagnetic rays to the Moessbauer conversion electron spectrum

International Nuclear Information System (INIS)

Ruskov, T.; Ruskov, R.; Paneva, D.; Lefterov, D.

1999-01-01

The contribution of back-scattered electromagnetic rays in a 57 Fe conversion electron Moessbauer spectrum is considered using proportional counter as a detector. A simplified method for measuring this contribution is described. The experimental results show that this contribution strongly depends on the construction of the counter and the selected fraction in the pulse-height spectrum

Baryon superfluids in AdS/CFT with flavor

Energy Technology Data Exchange (ETDEWEB)

Hoyos, Carlos [Department of Physics, Universidad de Oviedo,Avda. Calvo Sotelo 18, ES-33007 Oviedo (Spain); Itsios, Georgios [Department of Physics, Universidad de Oviedo,Avda. Calvo Sotelo 18, ES-33007 Oviedo (Spain); Instituto de Física Teórica, UNESP-Universidade Estadual Paulista,R. Dr. Bento T. Ferraz 271, Bl. II, Sao Paulo 01140-070, SP (Brazil); Vasilakis, Orestis [Department of Physics, Universidad de Oviedo,Avda. Calvo Sotelo 18, ES-33007 Oviedo (Spain)

2017-01-31

Baryonic matter is notoriously difficult to deal with in the large-N limit, as baryons become operators of very large dimension with N fields in the fundamental representation. This issue is also present in gauge/gravity duals as baryons are described by very heavy localized objects. There are however alternative large-N extrapolations of QCD where small baryonic operators exist and can be treated on an equal footing to mesons. We explore the possibility of turning on a finite density of “light” baryons in a theory with a hadronic mass gap using a gauge/gravity construction based on the D3/D7 intersection. We find a novel phase with spontaneous breaking of baryon symmetry at zero temperature.

Non-charm hadronic decays of bottom baryons

International Nuclear Information System (INIS)

Kohara, Y.

1999-01-01

Two-body decay amplitudes of antitriplet bottom baryons Λ 0b , Θ 0 b and Θ -b to a decuplet baryon and a pseudoscalar meson are analyzed on the basis of the quark diagram scheme. Relations among the various decay rates to decuplet baryons are derived

Precombination Cloud Collapse and Baryonic Dark Matter

Science.gov (United States)

Hogan, Craig J.

1993-01-01

A simple spherical model of dense baryon clouds in the hot big bang 'strongly nonlinear primordial isocurvature baryon fluctuations' is reviewed and used to describe the dependence of cloud behavior on the model parameters, baryon mass, and initial over-density. Gravitational collapse of clouds before and during recombination is considered including radiation diffusion and trapping, remnant type and mass, and effects on linear large-scale fluctuation modes. Sufficiently dense clouds collapse early into black holes with a minimum mass of approx. 1 solar mass, which behave dynamically like collisionless cold dark matter. Clouds below a critical over-density, however, delay collapse until recombination, remaining until then dynamically coupled to the radiation like ordinary diffuse baryons, and possibly producing remnants of other kinds and lower mass. The mean density in either type of baryonic remnant is unconstrained by observed element abundances. However, mixed or unmixed spatial variations in abundance may survive in the diffuse baryon and produce observable departures from standard predictions.

Search for Baryons with Two Charm Quarks

Energy Technology Data Exchange (ETDEWEB)

Mattson, Mark Edward [Carnegie Mellon U.

2002-01-01

Using data from the SELEX experiment, we searched for baryons having two charm quarks. No one has yet observed a doubly-charmed baryon. We investigated the reconstruction $\\Lambda^+_c K⁻ \\pi^+\\pi^+$, a decay mode consistent with a baryon having $ccu$ quarks. We observe an excess of 20 events above an expected background of 31 events, at a mass of 3.76 GeV/$c^2$. We observe differences between the signal events and the background. The mass resolution, mass, and decay mode are consistent with a $ccu$ baryon. The mass and production are higher than theoretical predictions for the ground state $\\Xi^{++}_{cc}$. If the signal is real and not a doubly-charmed baryon, then it is not accounted for by current physics

On the baryon magnetic moments

International Nuclear Information System (INIS)

Ferreira, P.L.

1976-01-01

In the context of quark confinement ideas, the baryon magnetic moments are calculated by assuming a SU(3) breaking due to the inequalities of the quark masses (m sub(p) different m sub(n) different m lambda ). The modified SU(6) result for the ratio of the magnetic moments of the neutron and proton is obtained. The p-quark is found heavier than the n-quark by circa 15 MeV. and alternative way of evaluating the baryon magnetic moments by means of simple physical considerations based on the properties of the SU(6) baryon S-waves functions is given

Does dark matter consist of baryons of new stable family quarks?

International Nuclear Information System (INIS)

Bregar, G.; Mankoc Borstnik, N. S.

2009-01-01

We investigate the possibility that the dark matter consists of clusters of the heavy family quarks and leptons with zero Yukawa couplings to the lower families. Such a family is predicted by the approach unifying spin and charges as the fifth family. We make a rough estimation of properties of baryons of these new family members, of their behavior during the evolution of the Universe and when scattering on the ordinary matter, and study possible limitations on the family properties due to the cosmological and direct experimental evidences.

S-matrix analysis of the baryon electric charge correlation

Science.gov (United States)

Lo, Pok Man; Friman, Bengt; Redlich, Krzysztof; Sasaki, Chihiro

2018-03-01

We compute the correlation of the net baryon number with the electric charge (χBQ) for an interacting hadron gas using the S-matrix formulation of statistical mechanics. The observable χBQ is particularly sensitive to the details of the pion-nucleon interaction, which are consistently incorporated in the current scheme via the empirical scattering phase shifts. Comparing to the recent lattice QCD studies in the (2 + 1)-flavor system, we find that the natural implementation of interactions and the proper treatment of resonances in the S-matrix approach lead to an improved description of the lattice data over that obtained in the hadron resonance gas model.

Anomalous Dimensions of Conformal Baryons

DEFF Research Database (Denmark)

Pica, Claudio; Sannino, Francesco

2016-01-01

We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small, within...

Baryonic Higgs at the LHC

Energy Technology Data Exchange (ETDEWEB)

Duerr, Michael [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fileviez Perez, Pavel [Case Western Reserve Univ., Cleveland, OH (United States). CERCA, Physics Dept.; Smirnov, Juri [INFN, Sezione di Firenze (Italy); Florence Univ., Sesto Fiorentino (Italy). Dept. of Physics and Astronomy

2017-04-15

We investigate the possible collider signatures of a new Higgs in simple extensions of the Standard Model where baryon number is a local symmetry spontaneously broken at the low scale. We refer to this new Higgs as ''Baryonic Higgs''. This Higgs has peculiar properties since it can decay into all Standard Model particles, the leptophobic gauge boson, and the vector-like quarks present in these theories to ensure anomaly cancellation. We investigate in detail the constraints from the γγ, Zγ, ZZ, and WW searches at the Large Hadron Collider, needed to find a lower bound on the scale at which baryon number is spontaneously broken. The di-photon channel turns out to be a very sensitive probe in the case of small scalar mixing and can severely constrain the baryonic scale. We also study the properties of the leptophobic gauge boson in order to understand the testability of these theories at the LHC.

Isospin violation in low-energy pion-nucleon scattering revisited

Energy Technology Data Exchange (ETDEWEB)

Hoferichter, Martin, E-mail: hoferichter@hiskp.uni-bonn.d [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (IKP-3), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)

2010-02-01

We calculate isospin breaking in pion-nucleon scattering in the threshold region in the framework of covariant baryon chiral perturbation theory. All effects due to quark mass differences as well as real and virtual photons are consistently included. As an application, we discuss the energy dependence of the triangle relation that connects elastic scattering on the proton pi{sup +}-p->pi{sup +}-p with the charge exchange reaction pi{sup -}p->pi{sup 0}n.

Isospin violation in low-energy pion-nucleon scattering revisited

International Nuclear Information System (INIS)

Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.

2010-01-01

We calculate isospin breaking in pion-nucleon scattering in the threshold region in the framework of covariant baryon chiral perturbation theory. All effects due to quark mass differences as well as real and virtual photons are consistently included. As an application, we discuss the energy dependence of the triangle relation that connects elastic scattering on the proton π ± p→π ± p with the charge exchange reaction π - p→π 0 n.

Isospin splittings of baryons

International Nuclear Information System (INIS)

Varga, Kalman; Genovese, Marco; Richard, Jean-Marc; Silvestre-Brac, Bernard

1998-01-01

We discuss the isospin-breaking mass differences among baryons, with particular attention in the charm sector to the Σ c + -Σ c 0 , Σ c ++ -Σ c 0 , and Ξ c + -Ξ c 0 splittings. Simple potential models cannot accommodate the trend of the available data on charm baryons. More precise measurements would offer the possibility of testing how well potential models describe the non-perturbative limit of QCD

Baryon exchange effects in dual unitarisation

International Nuclear Information System (INIS)

Hong-Mo, C.; Tsun, T.S.

1976-05-01

The effects of baryon exchanges in the renormalisation of Regge trajectories are studied in the dual unitarisation scheme. The main results are that: (i) the Pomeron is boosted above α = 1, giving rising total cross sections beyond baryon-antibaryon thresholds, and (ii) the ω-trajectory remains approximately at α = .5 but acquires a sizeable admixture of the exotic antiq antiq qq state, which enhances its coupling to baryons. There are in addition a number of other interesting predictions. (author)

Baryon asymmetry, inflation and squeezed states

International Nuclear Information System (INIS)

Bambah, Bindu A.; Chaitanya, K.V.S. Shiv; Mukku, C.

2007-01-01

We use the general formalism of squeezed rotated states to calculate baryon asymmetry in the wake of inflation through parametric amplification. We base our analysis on a B and CP violating Lagrangian in an isotropically expanding universe. The B and CP violating terms originate from the coupling of complex fields with non-zero baryon number to a complex background inflaton field. We show that a differential amplification of particle and antiparticle modes gives rise to baryon asymmetry

Meson and baryon spectrum for QCD with two light dynamical quarks

Science.gov (United States)

Engel, Georg P.; Lang, C. B.; Limmer, Markus; Mohler, Daniel; Schäfer, Andreas

2010-08-01

We present results of meson and baryon spectroscopy using the Chirally Improved Dirac operator on lattices of size 163×32 with two mass-degenerate light sea quarks. Three ensembles with pion masses of 322(5), 470(4), and 525(7) MeV and lattice spacings close to 0.15 fm are investigated. Results for ground and excited states for several channels are given, including spin two mesons and hadrons with strange valence quarks. The analysis of the states is done with the variational method, including two kinds of Gaussian sources and derivative sources. We obtain several ground states fairly precisely and find radial excitations in various channels. Excited baryon results seem to suffer from finite size effects, in particular, at small pion masses. We discuss the possible appearance of scattering states, considering masses and eigenvectors. Partially quenched results in the scalar channel suggest the presence of a 2-particle state, however, in most channels we cannot identify them. Where available, we compare our results to results of quenched simulations using the same action.

Meson and baryon spectrum for QCD with two light dynamical quarks

International Nuclear Information System (INIS)

Engel, Georg P.; Lang, C. B.; Limmer, Markus; Mohler, Daniel; Schaefer, Andreas

2010-01-01

We present results of meson and baryon spectroscopy using the Chirally Improved Dirac operator on lattices of size 16 3 x32 with two mass-degenerate light sea quarks. Three ensembles with pion masses of 322(5), 470(4), and 525(7) MeV and lattice spacings close to 0.15 fm are investigated. Results for ground and excited states for several channels are given, including spin two mesons and hadrons with strange valence quarks. The analysis of the states is done with the variational method, including two kinds of Gaussian sources and derivative sources. We obtain several ground states fairly precisely and find radial excitations in various channels. Excited baryon results seem to suffer from finite size effects, in particular, at small pion masses. We discuss the possible appearance of scattering states, considering masses and eigenvectors. Partially quenched results in the scalar channel suggest the presence of a 2-particle state, however, in most channels we cannot identify them. Where available, we compare our results to results of quenched simulations using the same action.

Hadronic light-by-light scattering contribution to the muon g-2

International Nuclear Information System (INIS)

Nyffeler, A.

2010-01-01

We review recent developments concerning the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. We first discuss why fully off-shell hadronic form factors should be used for the evaluation of this contribution to the g-2. We then reevaluate the numerically dominant pion-exchange contribution in the framework of large-N C QCD, using an off-shell pion-photon-photon form factor which fulfills all QCD short-distance constraints,in particular, a new short-distance constraint on the off-shell form factor at the external vertex in g-2, which relates the form factor to the quark condensate magnetic susceptibility in QCD. Combined with available evaluations of the other contributions to hadronic light-by-light scattering this leads to the new result α μ LbyL;had =(116 ± 40) x 10 -11 , with a conservative error estimate in view of the many still unsolved problems. Some potential ways for further improvements are briefly discussed as well. For the electron we obtain the new estimate α e LbyL;had =(3.9 ± 1.3) x 10 -14 . (author)

Quark-diagram analysis of charmed-baryon decays

International Nuclear Information System (INIS)

Kohara, Y.

1991-01-01

The Cabibbo-allowed two-body nonleptonic decays of charmed baryons to a SU(3)-octet (or -decuplet) baryon and a pseudoscalar meson are examined on the basis of the quark-diagram scheme. Some relations among the decay amplitudes or rates of various decay modes are derived. The decays of Ξ c + to a decuplet baryon are forbidden

Electric form factors of the octet baryons from lattice QCD and chiral extrapolation

International Nuclear Information System (INIS)

Shanahan, P.E.; Thomas, A.W.; Young, R.D.; Zanotti, J.M.; Pleiter, D.; Stueben, H.

2014-03-01

We apply a formalism inspired by heavy baryon chiral perturbation theory with finite-range regularization to dynamical 2+1-flavor CSSM/QCDSF/UKQCD Collaboration lattice QCD simulation results for the electric form factors of the octet baryons. The electric form factor of each octet baryon is extrapolated to the physical pseudoscalar masses, after finite-volume corrections have been applied, at six fixed values of Q 2 in the range 0.2-1.3 GeV 2 . The extrapolated lattice results accurately reproduce the experimental form factors of the nucleon at the physical point, indicating that omitted disconnected quark loop contributions are small. Furthermore, using the results of a recent lattice study of the magnetic form factors, we determine the ratio μ p G E p /G M p . This quantity decreases with Q 2 in a way qualitatively consistent with recent experimental results.

Elastic pion-nucleon P-wave scattering in soliton models

International Nuclear Information System (INIS)

Holzwarth, G.

1990-01-01

The equivalence of low-energy P-wave πN scattering in soliton models with the well-established Δ-isobar model is shown to hold even if all constraints on redundant collective variables are ignored. This provides strong support for the unusual (time-derivative) form of meson-baryon coupling in such models, and for the expectation that the soliton description of πN-scattering can be reliably extended down to pion threshold energies in a technically simple way. (orig.)

Baryon distribution in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Wong, C.

1984-01-01

In order to determine whether a pure quark-gluon plasma with no net baryon density can be formed in the central rapidity region in relativistic heavy-ion collisions, we estimate the baryon distribution by using a Glauber-type multiple-collision model in which the nucleons of one nucleus degrade in energy as they make collisions with nucleons in the other nucleus. As a test of this model, we study first nucleon-nucleus collisions at 100 GeV/c and compare the theoretical results with the experimental data of Barton et al. The results are then generalized to study the baryon distribution in nucleus-nucleus collisions. It is found that in the head-on collision of two heavy nuclei (A> or approx. =100), the baryon rapidity distributions have broad peaks and extend well into the central rapidity region. The energy density of the baryon in the central rapidity region is about 5--6 % of the total energy density at a center-of-mass energy of 30 GeV per nucleon and decreases to about 2--3 % at a center-of-mass energy of 100 GeV per nucleon. The stopping power for a baryon in nuclear matter is extracted

Equation of state of dense baryonic matter

International Nuclear Information System (INIS)

Weber, F.; Weigel, M.K.

1989-01-01

In a previous investigation we treated nuclear matter as well as neutron matter at zero and finite temperatures in the frame of different relativistic field theoretical models, but with the restriction to nucleons as the only present baryons. This approach is extended by including a larger fraction of baryons and mesons, necessary for a description of baryon matter under extreme conditions. The equation of state (EOS) is calculated in both the Hartree and Hartree-Fock (HF) approximations for dense nuclear as well as neutron matter. Self-interactions of the σ field up to fourth order have been taken into account. For the treatment of many-baryon matter in the HF approach the parameters of the theory had to be readjusted. A phase transition of both many-baryon systems (neutron as well as nuclear matter) in the high-pressure and high-energy-density region has been found. (author)

Baryons in QCDAS at large Nc: A roundabout approach

International Nuclear Information System (INIS)

Cohen, Thomas D.; Shafer, Daniel L.; Lebed, Richard F.

2010-01-01

QCD AS , a variant of large N c QCD in which quarks transform under the color two-index antisymmetric representation, reduces to standard QCD at N c =3 and provides an alternative to the usual large N c extrapolation that uses fundamental representation quarks. Previous strong plausibility arguments assert that the QCD AS baryon mass scales as N c 2 ; however, the complicated combinatoric problem associated with quarks carrying two color indices impeded a complete demonstration. We develop a diagrammatic technique to solve this problem. The key ingredient is the introduction of an effective multigluon vertex: a ''traffic circle'' or roundabout diagram. We show that arbitrarily complicated diagrams can be reduced to simple ones with the same leading N c scaling using this device, and that the leading contribution to baryon mass does, in fact, scale as N c 2 .

Phenomenology of Baryon Resonances

Energy Technology Data Exchange (ETDEWEB)

Doring, Michael [George Washington Univ., Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Landay, Justin [George Washington Univ., Washington, DC (United States); Mai, Maxim [George Washington Univ., Washington, DC (United States); Molina, Raquel [Univ. of Sao Paulo (Brazil); Ronchen, Deborah [Univ. of Bonn (Germany)

2018-04-01

Results for light baryon spectroscopy by different collaborations and the state of the art in the subfield is reviewed. Highlights contain common efforts of different phenomenology groups and the impact of recent high-precision data from ELSA, JLab, MAMI, and other facilities. Questions will be addressed, on one side, of how to proceed to reach conclusive answers in baryon spectroscopy, and, on the other side, how phenomenology can be connected to theory in a meaningful way.

The baryonic mass function of galaxies.

Science.gov (United States)

Read, J I; Trentham, Neil

2005-12-15

In the Big Bang about 5% of the mass that was created was in the form of normal baryonic matter (neutrons and protons). Of this about 10% ended up in galaxies in the form of stars or of gas (that can be in molecules, can be atomic, or can be ionized). In this work, we measure the baryonic mass function of galaxies, which describes how the baryonic mass is distributed within galaxies of different types (e.g. spiral or elliptical) and of different sizes. This can provide useful constraints on our current cosmology, convolved with our understanding of how galaxies form. This work relies on various large astronomical surveys, e.g. the optical Sloan Digital Sky Survey (to observe stars) and the HIPASS radio survey (to observe atomic gas). We then perform an integral over our mass function to determine the cosmological density of baryons in galaxies: Omega(b,gal)=0.0035. Most of these baryons are in stars: Omega(*)=0.0028. Only about 20% are in gas. The error on the quantities, as determined from the range obtained between different methods, is ca 10%; systematic errors may be much larger. Most (ca 90%) of the baryons in the Universe are not in galaxies. They probably exist in a warm/hot intergalactic medium. Searching for direct observational evidence and deeper theoretical understanding for this will form one of the major challenges for astronomy in the next decade.

P11 πN scattering in a potential model and in the cloudy bag model

International Nuclear Information System (INIS)

Rinat, A.S.

1982-01-01

We discuss P 11 πN scattering in a model where the π is coupled to quark bags for baryons N, R, Δ. From the underlying qqπ couplings we derive B'Bπ vertices which are used in a solution of a πN, πΔ two-channel scattering problem. Using one bag radius from a fit to P 33 πN data, we are unable to reproduce delta 11 . A fit requires a Roper radius Rsub(R) > Rsub(N). We discuss the sensitivity of the fit to small variations in other bag parameters. The theory is compared with a simple potential model and with field theories employing baryons instead of quark fields. (orig.)

SU(3) flavour breaking and baryon structure

Energy Technology Data Exchange (ETDEWEB)

Cooke, A.N.; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo (Japan); Pleiter, D. [Forschungszentrum Juelich GmbH (Germany). Juelich Supercomputing Centre (JSC); Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Shanahan, P.; Zanotti, J.M. [Adelaide Univ., SA (Australia). CSSM, School of Chemistry and Physics; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Stueben, H. [Hamburg Univ. (Germany). Regionales Rechenzentrum; Collaboration: QCDSF/UKQCD Collaboration

2013-11-15

We present results from the QCDSF/UKQCD collaboration for hyperon electromagnetic form factors and axial charges obtained from simulations using N{sub f}=2+1 flavours of O(a)-improved Wilson fermions. We also consider matrix elements relevant for hyperon semileptonic decays. We find flavour-breaking effects in hyperon magnetic moments which are consistent with experiment, while our results for the connected quark spin content indicates that quarks contribute more to the spin of the {Xi} baryon than they do to the proton.

CP violation in the baryon sector

CERN Document Server

Smith, Eluned Anne

2017-01-01

The study of CP violation in the baryon sector is still a relatively new field and offers the possibility to make many CP measurements which could complement those performed in the meson sector. This is especially true of late given the large number of baryons currently being produced at the LHC. Such measurements could help further over-constrain the CKM unitary triangle, as well as furthering our understand of baryongenesis. These proceedings will give an overview of the current state of the search for CP violation in the baryon sector.

QCD inequalities for the nucleon mass and the free energy of baryonic matter.

Science.gov (United States)

Cohen, Thomas D

2003-07-18

The positivity of the integrand of certain Euclidean space functional integrals for two flavor QCD with degenerate quark masses implies that the free energy per unit volume for QCD with a baryon chemical potential mu(B) (and zero isospin chemical potential) is greater than the free energy with an isospin chemical potential mu(I)=(2 mu(B)/N(c)) (and zero baryon chemical potential). The same result applies to QCD with any number of heavy flavors in addition to the two light flavors so long as the chemical potential is understood as applying to the light quark contributions to the baryon number. This relation implies a bound on the nucleon mass: there exists a particle X in QCD (presumably the pion) such that M(N)> or =(N(c) m(X)/2 I(X)) where m(X) is the mass of the particle and I(X) is its isospin.

Electric form factors of the octet baryons from lattice QCD and chiral extrapolation

Energy Technology Data Exchange (ETDEWEB)

Shanahan, P.E.; Thomas, A.W.; Young, R.D.; Zanotti, J.M. [Adelaide Univ., SA (Australia). ARC Centre of Excellence in Particle Physics at the Terascale and CSSM; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo (Japan); Pleiter, D. [Forschungszentrum Juelich (Germany). JSC; Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Stueben, H. [Hamburg Univ. (Germany). Regionales Rechenzentrum; Collaboration: CSSM and QCDSF/UKQCD Collaborations

2014-03-15

We apply a formalism inspired by heavy baryon chiral perturbation theory with finite-range regularization to dynamical 2+1-flavor CSSM/QCDSF/UKQCD Collaboration lattice QCD simulation results for the electric form factors of the octet baryons. The electric form factor of each octet baryon is extrapolated to the physical pseudoscalar masses, after finite-volume corrections have been applied, at six fixed values of Q{sup 2} in the range 0.2-1.3 GeV{sup 2}. The extrapolated lattice results accurately reproduce the experimental form factors of the nucleon at the physical point, indicating that omitted disconnected quark loop contributions are small. Furthermore, using the results of a recent lattice study of the magnetic form factors, we determine the ratio μ{sub p}G{sub E}{sup p}/G{sub M}{sup p}. This quantity decreases with Q{sup 2} in a way qualitatively consistent with recent experimental results.

Improved bag models of P-wave baryons

International Nuclear Information System (INIS)

Wang Fan; Wong Chunwa

1988-01-01

Problems in two previous bag-model calculations of P-wave baryon states are pointed out. The two-body matrix elements used in one of these models, the Myhrer-Wroldsen bag model, have now been revised and corrected by Myhrer, Umino and Wroldsen. We use their corrected matrix elements to construct simple bag models in which baryon masses are stabilized against collapse by using a finite pion size. We find that baryon masses in both ground and excited states can be fitted with the same model parameters. Models with small-bag baryons of the type proposed by Brown and Rho are then obtained. Typical bag radii are 0.5 fm for N, 0.6 fm for Δ and 0.7 fm for P-wave nonstrange baryons. In these models, the mixing angles are still unsatisfactory, while inadequacy in the treatment of center-of-mass motion found in an earlier paper persists. These results are briefly discussed. especially in connection with skyrmion models. (orig.)

Lattice QCD evaluation of baryon magnetic moment sum rules

International Nuclear Information System (INIS)

Leinweber, D.B.

1991-05-01

Magnetic moment combinations and sum rules are evaluated using recent results for the magnetic moments of octet baryons determined in a numerical simulation of quenched QCD. The model-independent and parameter-free results of the lattice calculations remove some of the confusion and contradiction surrounding past magnetic moment sum rule analyses. The lattice results reveal the underlying quark dynamics investigated by magnetic moment sum rules and indicate the origin of magnetic moment quenching for the non-strange quarks in Σ. In contrast to previous sum rule analyses, the magnetic moments of nonstrange quarks in Ξ are seen to be enhanced in the lattice results. In most cases, the spin-dependent dynamics and center-of-mass effects giving rise to baryon dependence of the quark moments are seen to be sufficient to violate the sum rules in agreement with experimental measurements. In turn, the sum rules are used to further examine the results of the lattice simulation. The Sachs sum rule suggests that quark loop contributions not included in present lattice calculations may play a key role in removing the discrepancies between lattice and experimental ratios of magnetic moments. This is supported by other sum rules sensitive to quark loop contributions. A measure of the isospin symmetry breaking in the effective quark moments due to quark loop contributions is in agreement with model expectations. (Author) 16 refs., 2 figs., 2 tabs

Study of Charm Baryons with the BaBar Experiment

International Nuclear Information System (INIS)

Petersen, Brian Aa.

2006-01-01

The authors report on several studies of charm baryon production and decays by the BABAR collaboration. They confirm previous observations of the Ξ' c 0/+ , Ξ c (2980) + and Ξ c (3077) + baryons, measure branching ratios for Cabibbo-suppressed Λ c + decays and use baryon decays to study the properties of the light-quark baryons, (Omega) - and Ξ(1690) 0

Magnetic moments of triply heavy baryons in quark-diquark model

International Nuclear Information System (INIS)

Thakkar, Kaushal; Majethiya, Ajay; Vinodkumar, P.C.

2016-01-01

Along with the well-established triply flavoured (uuu) and strange (sss) baryons, QCD predicts similar states made up of charm quarks, the triply-charmed baryon, ccc and bottom quarks, the triply-bottom baryon, bbb. Such a state has yet to be observed experimentally. After the observation of the doubly charmed baryon by the SELEX group, it is expected that the triply heavy flavour baryonic state may be in the offing very soon. Though considerable amount of data on the properties of the singly-heavy baryons are available in literature, only sparse attention has been paid to the spectroscopy of double and triple-heavy flavour baryons, perhaps mainly due to the lack of experimental incentives

Compressed Baryonic Matter of Astrophysics

OpenAIRE

Guo, Yanjun; Xu, Renxin

2013-01-01

Baryonic matter in the core of a massive and evolved star is compressed significantly to form a supra-nuclear object, and compressed baryonic matter (CBM) is then produced after supernova. The state of cold matter at a few nuclear density is pedagogically reviewed, with significant attention paid to a possible quark-cluster state conjectured from an astrophysical point of view.

Hyperons: Insights into baryon structures

International Nuclear Information System (INIS)

Lach, J.

1991-08-01

The baryon octet is composed mainly of hyperons. Modern high energy hyperon beams provide a tool for the study of hyperon static properties and interactions. Experiments with these beams have provided new insights into hyperon rare decays, magnetic moments, and interactions. These experiments provide us with insights into the strong, weak, and electromagnetic structure of the baryons. 65 refs., 45 figs., 5 tabs

Heavy flavor baryons in hypercentral model

Indian Academy of Sciences (India)

Keywords. Hypercentral constituent quark model; charmed and beauty baryons; hyper-Coulomb plus power potential. Abstract. Heavy flavor baryons containing single and double charm (beauty) quarks with light flavor combinations are studied using the hypercentral description of the three-body problem. The confinement ...

e+e--annihilation into baryon-antibaryon pairs

International Nuclear Information System (INIS)

Koerner, J.G.; Kuroda, M.

1976-07-01

Using GVDM-type form factors we calculate the e + -e - production cross sections for the reactions e + e - → 1 + /2 - anti(1 +- /2), 1 + /2 - anti(3 +- /2), 1 + /2 - anti(5 + /2) and 3 + /2 - anti(3 + /2) including all prominent baryon resonances at energies of present and planned e + -e - storage ring machines. We also evaluate the cross section of charmed baryon pair production. Near their respective thresholds charmed and uncharmed baryon pair production are predicted to constitute comparable fractions of the total hadronic cross section. The calculated cross sections indicate that the interference of direct and 1-photon decay of the PSI-particles into baryon pairs is small. (orig.) [de

Baryon density in alternative BBN models

International Nuclear Information System (INIS)

Kirilova, D.

2002-10-01

We present recent determinations of the cosmological baryon density ρ b , extracted from different kinds of observational data. The baryon density range is not very wide and is usually interpreted as an indication for consistency. It is interesting to note that all other determinations give higher baryon density than the standard big bang nucleosynthesis (BBN) model. The differences of the ρ b values from the BBN predicted one (the most precise today) may be due to the statistical and systematic errors in observations. However, they may be an indication of new physics. Hence, it is interesting to study alternative BBN models, and the possibility to resolve the discrepancies. We discuss alternative cosmological scenarios: a BBN model with decaying particles (m ∼ MeV, τ ∼ sec) and BBN with electron-sterile neutrino oscillations, which permit to relax BBN constraints on the baryon content of the Universe. (author)

Nucleon-deuteron scattering with Δ-isobar excitation: Perturbation theory

International Nuclear Information System (INIS)

Deltuva, A.; Chmielewski, K.; Sauer, P.U.

2003-01-01

A perturbative approach for the description of elastic and inelastic nucleon-deuteron scattering is developed. Its validity is discussed. The aim of the perturbative approach is the isolation of details of different reaction mechanisms. The dynamics is based on a two-baryon potential allowing for the excitation of a nucleon to a Δ isobar. The coupled-channel potential yields an effective three-nucleon force in three-nucleon scattering. The purely nucleonic reference potential is the charge-dependent CD-Bonn potential

Chiral properties of baryon interpolating fields

International Nuclear Information System (INIS)

Nagata, Keitaro; Hosaka, Atsushi; Dmitrasinovic, V.

2008-01-01

We study the chiral transformation properties of all possible local (non-derivative) interpolating field operators for baryons consisting of three quarks with two flavors, assuming good isospin symmetry. We derive and use the relations/identities among the baryon operators with identical quantum numbers that follow from the combined color, Dirac and isospin Fierz transformations. These relations reduce the number of independent baryon operators with any given spin and isospin. The Fierz identities also effectively restrict the allowed baryon chiral multiplets. It turns out that the non-derivative baryons' chiral multiplets have the same dimensionality as their Lorentz representations. For the two independent nucleon operators the only permissible chiral multiplet is the fundamental one, ((1)/(2),0)+(0,(1)/(2)). For the Δ, admissible Lorentz representations are (1,(1)/(2))+((1)/(2),1) and ((3)/(2),0)+(0,(3)/(2)). In the case of the (1,(1)/(2))+((1)/(2),1) chiral multiplet, the I(J)=(3)/(2)((3)/(2)) Δ field has one I(J)=(1)/(2)((3)/(2)) chiral partner; otherwise it has none. We also consider the Abelian (U A (1)) chiral transformation properties of the fields and show that each baryon comes in two varieties: (1) with Abelian axial charge +3; and (2) with Abelian axial charge -1. In case of the nucleon these are the two Ioffe fields; in case of the Δ, the (1,(1)/(2))+((1)/(2),1) multiplet has an Abelian axial charge -1 and the ((3)/(2),0)+(0,(3)/(2)) multiplet has an Abelian axial charge +3. (orig.)

Mirage in temporal correlation functions for baryon-baryon interactions in lattice QCD

International Nuclear Information System (INIS)

Iritani, T.; Doi, T.; Aoki, S.; Gongyo, S.; Hatsuda, T.; Ikeda, Y.; Inoue, T.; Ishii, N.; Murano, K.; Nemura, H.; Sasaki, K.

2016-01-01

Single state saturation of the temporal correlation function is a key condition to extract physical observables such as energies and matrix elements of hadrons from lattice QCD simulations. A method commonly employed to check the saturation is to seek for a plateau of the observables for large Euclidean time. Identifying the plateau in the cases having nearby states, however, is non-trivial and one may even be misled by a fake plateau. Such a situation takes place typically for a system with two or more baryons. In this study, we demonstrate explicitly the danger from a possible fake plateau in the temporal correlation functions mainly for two baryons (ΞΞ and NN), and three and four baryons ("3He and "4He) as well, employing (2+1)-flavor lattice QCD at m_π=0.51 GeV on four lattice volumes with L= 2.9, 3.6, 4.3 and 5.8 fm. Caution is required when drawing conclusions about the bound NN, 3N and 4N systems based only on the standard plateau fitting of the temporal correlation functions.

The Heavy Baryon Physics by means LEP

International Nuclear Information System (INIS)

Lesiak, T.

2000-07-01

This report describes the experimental research about the heavy baryons which were obtained in the last decade at LEP. The most important among them concern the lifetimes of beauty baryons. The methods of theoretical description of heavy hadrons together with the LEP experimental apparatus are also discussed. Heavy baryon studies are shown in a broader perspective of other LEP results: the test of the standard model and the latest measurements concerning the beauty mesons. (author)

Baryonic effects in cosmic shear tomography: PCA parametrization and importance of extreme baryonic models

Energy Technology Data Exchange (ETDEWEB)

Mohammed, Irshad [Fermilab; Gnedin, Nickolay Y. [Fermilab

2017-07-07

Baryonic effects are amongst the most severe systematics to the tomographic analysis of weak lensing data which is the principal probe in many future generations of cosmological surveys like LSST, Euclid etc.. Modeling or parameterizing these effects is essential in order to extract valuable constraints on cosmological parameters. In a recent paper, Eifler et al. (2015) suggested a reduction technique for baryonic effects by conducting a principal component analysis (PCA) and removing the largest baryonic eigenmodes from the data. In this article, we conducted the investigation further and addressed two critical aspects. Firstly, we performed the analysis by separating the simulations into training and test sets, computing a minimal set of principle components from the training set and examining the fits on the test set. We found that using only four parameters, corresponding to the four largest eigenmodes of the training set, the test sets can be fitted thoroughly with an RMS $\\sim 0.0011$. Secondly, we explored the significance of outliers, the most exotic/extreme baryonic scenarios, in this method. We found that excluding the outliers from the training set results in a relatively bad fit and degraded the RMS by nearly a factor of 3. Therefore, for a direct employment of this method to the tomographic analysis of the weak lensing data, the principle components should be derived from a training set that comprises adequately exotic but reasonable models such that the reality is included inside the parameter domain sampled by the training set. The baryonic effects can be parameterized as the coefficients of these principle components and should be marginalized over the cosmological parameter space.

Baryon excitations in the bag model

International Nuclear Information System (INIS)

Jaffe, R.L.

1976-07-01

Two recent spectroscopic applications of the bag model are discussed. The first is a study of the place of multiquark states in meson and baryon spectroscopy, and the second is an attempt to sort out the P-wave baryon excitations in a bag model. 33 references

Antiproton-Proton Glory Scattering

CERN Multimedia

2002-01-01

This experiment measures @*p and K|-p backwards scattering between 8 and 16 GeV/c in the Omega spectrometer using the S1 beam, with sensitivities of several events per nanobarn. The mechanism responsible for backward scattering in channels not mediated by particle exchange is not understood, and could be almost energy-independent glory scattering, especially since relatively high cross sections of 190~(@*p) and 120~(K|-p)nb have been measured earlier at 5~GeV/c. @p|-p backwards scattering is measured for monitoring purposes. The trigger requires a forward particle of momentum close to the beam momentum. Absence of light in the two forward Cerenkov counters indicates that the particle is a proton. Combinations of an incident @p|- and an outgoing K|+, or an incident K|- or @* and an outgoing @p|+, cover the following byproducts: @*p~@A~@p|+@p|- which is an (allowed) baryon exchange reaction, and the exotic exchange reactions @p|-p~@A~K|+Y K|-p~@A~@p|+Y|-, where Y|- may be the @S|- or the Y*|-(1385).

Inside charged black holes. II. Baryons plus dark matter

International Nuclear Information System (INIS)

Hamilton, Andrew J.S.; Pollack, Scott E.

2005-01-01

This is the second of two companion papers on the interior structure of self-similar accreting charged black holes. In the first paper, the black hole was allowed to accrete only a single fluid of charged baryons. In this second paper, the black hole is allowed to accrete in addition a neutral fluid of almost noninteracting dark matter. Relativistic streaming between outgoing baryons and ingoing dark matter leads to mass inflation near the inner horizon. When enough dark matter has been accreted that the center-of-mass frame near the inner horizon is ingoing, then mass inflation ceases and the fluid collapses to a central singularity. A null singularity does not form on the Cauchy horizon. Although the simultaneous presence of ingoing and outgoing fluids near the inner horizon is essential to mass inflation, reducing one or the other of the ingoing dark matter or outgoing baryonic streams to a trace relative to the other stream makes mass inflation more extreme, not the other way around as one might naively have expected. Consequently, if the dark matter has a finite cross section for being absorbed into the baryonic fluid, then the reduction of the amount of ingoing dark matter merely makes inflation more extreme, the interior mass exponentiating more rapidly and to a larger value before mass inflation ceases. However, if the dark matter absorption cross section is effectively infinite at high collision energy, so that the ingoing dark matter stream disappears completely, then the outgoing baryonic fluid can drop through the Cauchy horizon. In all cases, as the baryons and the dark matter voyage to their diverse fates inside the black hole, they only ever see a finite amount of time pass by in the outside universe. Thus the solutions do not depend on what happens in the infinite past or future. We discuss in some detail the physical mechanism that drives mass inflation. Although the gravitational force is inward, inward means opposite direction for ingoing and

Photoproduction of hermaphrodite baryons

International Nuclear Information System (INIS)

Barnes, T.; Close, F.E.

1983-02-01

It is shown that photoexcitation of the lightest hermaphrodite baryons is strongly suppressed from proton targets but allowed from neutrons, a result that is reminiscent of a quark model selection rule due to Moorhouse (Phys. Rev. Lett.; 16:772 (1966)). This is consistent with suggestions that the P 11 (1710) is the lightest q 3 G baryon and eliminates the possibility that the Roper resonance is dominantly an hermaphrodite state. Magnetic moments do not constrain the possibility of considerable mixing of q 3 G into the nucleon and delta's Fock space wavefunctions. (author)

Lifetime and production rate of beauty baryons from Z decays

CERN Document Server

Abreu, P; Adye, T; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Allport, P P; Almehed, S; Alvsvaag, S J; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barate, R; Barbiellini, Guido; Bardin, Dimitri Yuri; Barker, G J; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bocci, V; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Buys, A; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carrilho, P; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Daum, A; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; De Boeck, H; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Djama, F; Dolbeau, J; Dönszelmann, M; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Dupont, F; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Fenyuk, A; Ferrer, A; Filippas-Tassos, A; Firestone, A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fürstenau, H; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gibbs, M; Gillespie, D; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Gracco, Valerio; Graziani, E; Grosdidier, G; Gunnarsson, P; Günther, M; Guy, J; Haedinger, U; Hahn, F; Hahn, M; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Ioannou, P; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kalmus, George Ernest; Kapusta, F; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Köhne, J H; Köne, B; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kramer, P H; Krammer, Manfred; Kreuter, C; Królikowski, J; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Lokajícek, M; Loken, J G; López, J M; López-Fernandez, A; López-Aguera, M A; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, M; McNulty, M; Medbo, J; Meroni, C; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Negri, P; Némécek, S; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Ostankov, A P; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Piana, G; Pierre, F; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schneider, H; Schyns, M A E; Sciolla, G; Scuri, F; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Squarcia, S; Stäck, H; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stepaniak, K; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chikilev, O G; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Torassa, E; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Überschär, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Wehr, A; Weierstall, M; Weilhammer, Peter; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Wormser, G; Woschnagg, K; Yip, K; Zach, F; Zacharatou-Jarlskog, C; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G

1995-01-01

The production and decay of beauty baryons (b-baryons) have been studied using 1.7 \\times 10^6 Z hadronic decays collected by the DELPHI detector at LEP. Three different techniques were used to identify the b-baryons. The first method used pairs of a \\Lambda and a lepton to tag the b-baryon decay. The second method associated fully reconstructed \\Lambda_c baryons with leptons. The third analysis reconstructed the b-baryon decay points by forming secondary vertices from identified protons and muons of opposite sign. Using these methods the following production rates were measured: \\begin{eqnarray*} f(\\qb \\ra \\Bb) \\times \\BR(\\Bb \\ra \\mLs \\ell\\bar{\

Bi-local baryon interpolating fields with two flavors

Energy Technology Data Exchange (ETDEWEB)

Dmitrasinovic, V. [Belgrade University, Institute of Physics, Pregrevica 118, Zemun, P.O. Box 57, Beograd (RS); Chen, Hua-Xing [Institutos de Investigacion de Paterna, Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Valencia (Spain); Peking University, Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Beijing (China)

2011-02-15

We construct bi-local interpolating field operators for baryons consisting of three quarks with two flavors, assuming good isospin symmetry. We use the restrictions following from the Pauli principle to derive relations/identities among the baryon operators with identical quantum numbers. Such relations that follow from the combined spatial, Dirac, color, and isospin Fierz transformations may be called the (total/complete) Fierz identities. These relations reduce the number of independent baryon operators with any given spin and isospin. We also study the Abelian and non-Abelian chiral transformation properties of these fields and place them into baryon chiral multiplets. Thus we derive the independent baryon interpolating fields with given values of spin (Lorentz group representation), chiral symmetry (U{sub L}(2) x U{sub R}(2) group representation) and isospin appropriate for the first angular excited states of the nucleon. (orig.)

Spectroscopy of doubly heavy baryons

International Nuclear Information System (INIS)

Gershtein, S.S.; Kiselev, V.V.; Likhoded, A.K.; Onishchenko, A.I.

2000-01-01

Within a nonrelativistic quark model featuring a QCD-motivated Buchmueller-Tye potential, the mass spectra for the families of doubly heavy baryons are calculated by assuming the quark-diquark structure of the baryon wave functions and by taking into account spin-dependent splitting. Physically motivated evidence that, in the case where heavy quarks have identical flavors, quasistationary excited states may be formed in the heavy-diquark subsystem is analyzed

A calculation of baryon diffusion constant in hot and dense hadronic matter based on an event generator URASiMA

International Nuclear Information System (INIS)

Sasaki, N.; Miyamura, O.; Nonaka, C.; Muroya, S.

2000-01-01

We evaluate thermodynamical quantities and transport coefficient of a dense and hot hadronic matter based on an event generator URASiMA (Ultra-Relativistic AA collision Simulator based on Multiple Scattering Algorithm). The statistical ensembles in equilibrium with fixed temperature and chemical potential are generated by imposing periodic boundary condition to the simulation of URASiMA, where energy density and baryon number density is conserved. Achievement of the thermal equilibrium and the chemical equilibrium are confirmed by the common value of slope parameter in the energy distributions and the saturation of the numbers of contained particles, respectively. By using the generated ensembles, we investigate the temperature dependence and the chemical potential dependence of the baryon diffusion constant of a dense and hot hadronic matter. (author)

The link between the baryonic mass distribution and the rotation curve shape

NARCIS (Netherlands)

Swaters, R. A.; Sancisi, R.; van der Hulst, J. M.; van Albada, T. S.

The observed rotation curves of disc galaxies, ranging from late-type dwarf galaxies to early-type spirals, can be fitted remarkably well simply by scaling up the contributions of the stellar and H?i discs. This baryonic scaling model can explain the full breadth of observed rotation curves with

Analysis of several ways to minimize the scatter contribution in radiographic digital images of offshore pipelines

Energy Technology Data Exchange (ETDEWEB)

Souza, Edmilson M.; Silva, Ademir X.; Lopes, Ricardo T., E-mail: emonteiro@nuclear.ufrj.b, E-mail: ademir@nuclear.ufrj.b, E-mail: Ricardo@lin.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Correa, Samanda C.A., E-mail: scorrea@cnen.gov.b [Comissao Nacional de Energia Nuclear (DIAPI/CGMI/CNEN), Rio de Janeiro, RJ (Brazil). Coordenacao Geral de Instalacoes Medicas e Industriais. Div. de Aplicacoes Industriais

2011-07-01

The aim of this work is to evaluate, through MCNPX simulations, several ways to minimize the scatter contribution in radiographic digital images of offshore pipelines. The influence of liquid inside the pipes and water surrounded the pipelines in the scatter contribution will be analyzed. The use of lead screen behind the detector to reduce the backscattered radiation and filter between the radiation source and the pipes will be discussed. (author)

Analysis of several ways to minimize the scatter contribution in radiographic digital images of offshore pipelines

International Nuclear Information System (INIS)

Souza, Edmilson M.; Silva, Ademir X.; Lopes, Ricardo T.; Correa, Samanda C.A.

2011-01-01

The aim of this work is to evaluate, through MCNPX simulations, several ways to minimize the scatter contribution in radiographic digital images of offshore pipelines. The influence of liquid inside the pipes and water surrounded the pipelines in the scatter contribution will be analyzed. The use of lead screen behind the detector to reduce the backscattered radiation and filter between the radiation source and the pipes will be discussed. (author)

Polarization effects in the reaction of charm baryon production on colliding electron-positron beams

International Nuclear Information System (INIS)

Rekalo, M.P.; Korzh, A.P.; Barannik, V.P.

1980-01-01

To calculate energy and angular distributions of various decay products of charm baAyons, which are prodUced in reactions on colliding e + e - beams, it is necessary to know the differential cross sections of the e + e - → C+anti C process which correspond to different polarized states of produced C and anti C (C - charm baryon). These differential cross sections are calculated for a single-photon mechanism with respect to the contribution of the anapole and electric dipole form factors of C-baryon. Polarizations of colliding electron-positron beams are taken into account in a full volume

Search for hybrid baryons with CLAS12 experimental setup

Energy Technology Data Exchange (ETDEWEB)

Lanza, Lucille [Univ. degli Studi di Roma Tor Vergata (Italy); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2017-03-01

It is crucial to study the meson electroproduction in the kinematic region dominated by the formation of resonances. CLAS12 setup in Hall B at Jefferson Lab is particularly suitable for this task, since it is able to detect scattered electrons at low polar angles thanks to the Forward Tagger (FT) component. The process that we propose to study is ep → e'K⁺Λ, where the electron beam will be provided by the CEBAF accelerator with energies of 6.6, 8.8, and 11 GeV. This thesis work describes the setup and calibration of the FT calorimeter and the studies related to the search of hybrid baryons through the measurement of the K⁺ Λ electroproduction cross section.

Excited State Contributions to the Heavy Baryon Fragmentation Functions in a Quark-Diquark Model

CERN Document Server

Adamov, A D; Goldstein, Gary R.

2001-01-01

Spin dependent fragmentation functions for heavy flavor quarks to fragment into heavy baryons are calculated in a quark-diquark model. The production of intermediate spin 1/2 and 3/2 excited states is explicity included. The resulting $\\Lambda_b$ production rate and polarization at LEP energies are in agreement with experiment. The $\\Lambda_c$ and $\\Xi_c$ functions are also obtained. The spin independent $f_1(z)$ is compared to data. The integrated values for production rates agree with the data.

Baryon spectroscopy and the omega minus

International Nuclear Information System (INIS)

Samios, N.P.

1994-01-01

In this report, I will mainly discuss baryon resonances with emphasis on the discovery of the Ω - . However, for completeness, I will also present some data on the meson resonances which together with the baryons led to the uncovering of the SU(3) symmetry of particles and ultimately to the concept of quarks

Strange baryons in a chiral quark-meson model. Pt. 2

International Nuclear Information System (INIS)

McGovern, J.A.; Birse, M.C.

1990-01-01

The chrial-quark meson model is used to study baryon properties with realistic breaking of SU(3). The symmetry breaking is assumed to be strong, so that a random phase approximation (RPA) can be used. In this the strange baryons are described as excitations built on the hedgehog soliton and have an excitation energy of 315 MeV. Other properties of strange baryons are obtained by an approximate spin-isospin projection from the RPA wave function. The magnetic moments agree reasonably well with experiment, but the deviations from the experimental values suggest that the method is valid for the case of rather stronger symmetry breaking than is realistic. The dependence of the RPA energy on the magnitude of the symmetry breaking is examined, and found to be strongly nonlinear for realistic values. This supports the idea that a large πN sigma commutator need not imply a large strange-quark content in the proton. For reasonable values of the scalar meson masses the strange-quark condensate is found to be less than 5% of the total, at the mean-field level. We also estimate the contribution to the condensate from RPA correlations. Within a one-mode approximation we find these to be very small, ≅ 2%. (orig.)

Calculation of baryon chemical potential and strangeness chemical potential in resonance matter

International Nuclear Information System (INIS)

Fu Yuanyong; Hu Shouyang; Lu Zhongdao

2006-01-01

Based on the high energy heavy-ion collisions statistical model, the baryon chemical potential and strangeness chemical potential are calculated for resonance matter with net baryon density and net strangeness density under given temperature. Furthermore, the relationship between net baryon density, net strangeness density and baryon chemical potential, strangeness chemical potential are analyzed. The results show that baryon chemical potential and strangeness chemical potential increase with net baryon density and net strangeness density increasing, the change of net baryon density affects baryon chemical potential and strangeness chemical potential more strongly than the change of net strangeness density. (authors)

Excitations of strange bottom baryons

Energy Technology Data Exchange (ETDEWEB)

Woloshyn, R.M. [TRIUMF, Vancouver, British Columbia (Canada)

2016-09-15

The ground-state and first-excited-state masses of Ω{sub b} and Ω{sub bb} baryons are calculated in lattice QCD using dynamical 2 + 1 flavour gauge fields. A set of baryon operators employing different combinations of smeared quark fields was used in the framework of the variational method. Results for radial excitation energies were confirmed by carrying out a supplementary multiexponential fitting analysis. Comparison is made with quark model calculations. (orig.)

Strange Baryon Physics in Full Lattice QCD

International Nuclear Information System (INIS)

Huey-Wen Lin

2007-01-01

Strange baryon spectra and form factors are key probes to study excited nuclear matter. The use of lattice QCD allows us to test the strength of the Standard Model by calculating strange baryon quantities from first principles

Baryon spectroscopy and the omega minus

Energy Technology Data Exchange (ETDEWEB)

Samios, N.P.

1994-12-31

In this report, I will mainly discuss baryon resonances with emphasis on the discovery of the {Omega}{sup {minus}}. However, for completeness, I will also present some data on the meson resonances which together with the baryons led to the uncovering of the SU(3) symmetry of particles and ultimately to the concept of quarks.

The baryon content of the Cosmic Web

Science.gov (United States)

Eckert, Dominique; Jauzac, Mathilde; Shan, HuanYuan; Kneib, Jean-Paul; Erben, Thomas; Israel, Holger; Jullo, Eric; Klein, Matthias; Massey, Richard; Richard, Johan; Tchernin, Céline

2015-01-01

Big-Bang nucleosynthesis indicates that baryons account for 5% of the Universe’s total energy content[1]. In the local Universe, the census of all observed baryons falls short of this estimate by a factor of two[2,3]. Cosmological simulations indicate that the missing baryons have not yet condensed into virialised halos, but reside throughout the filaments of the cosmic web: a low-density plasma at temperature 105–107 K known as the warm-hot intergalactic medium (WHIM)[3,4,5,6]. There have been previous claims of the detection of warm baryons along the line of sight to distant blazars[7,8,9,10] and hot gas between interacting clusters[11,12,13,14]. These observations were however unable to trace the large-scale filamentary structure, or to estimate the total amount of warm baryons in a representative volume of the Universe. Here we report X-ray observations of filamentary structures of ten-million-degree gas associated with the galaxy cluster Abell 2744. Previous observations of this cluster[15] were unable to resolve and remove coincidental X-ray point sources. After subtracting these, we reveal hot gas structures that are coherent over 8 Mpc scales. The filaments coincide with over-densities of galaxies and dark matter, with 5-10% of their mass in baryonic gas. This gas has been heated up by the cluster's gravitational pull and is now feeding its core. PMID:26632589

Two-body nonleptonic decays of charmed baryons

International Nuclear Information System (INIS)

Kohara, Y.

1998-01-01

Decay amplitudes of charmed baryons Λ c + , Ξ c 0 to an octet baryon and a pseudoscalar meson are calculated on the basis of the quark diagram scheme. restrictions imposed on the quark diagram amplitudes are also studied

Deeply virtual Compton scattering with the CLAS detector for the study of generalized parton distributions

International Nuclear Information System (INIS)

Girod, F.X.

2006-12-01

The structure of the nucleon, among the first fundamental problems in hadronic physics, is the subject of a renewed interest. The lightest baryonic state has historically been described in two complementary approaches: through elastic scattering, measuring form factors which reflect the spatial shape of charge distributions, and through deep inelastic scattering, providing access to parton distribution functions which encode the momentum content carried by the constituents. The recently developed formalism of Generalized Parton Distributions unifies those approaches and provides access to new informations. The cleanest process sensitive to GPDs is the deeply virtual Compton scattering (DVCS) contributing to the ep → epγ reaction. This work deals with a dedicated experiment accomplished with the CLAS detector, completed with two specific equipments: a lead tungstate calorimeter covering photon detection at small angles, and a superconducting solenoid actively shielding the electromagnetic background. The entire project is covered: from the upgrade of the experimental setup, through the update of the software, data taking and analysis, up to a first comparison of the beam spin asymmetry to model predictions. (author)

Evaluation of geometrical contributions to the spread of the Compton-scatter energy distribution

International Nuclear Information System (INIS)

Hanson, A.L.; Gigante, G.E.; Dipartimento di Fisica, Universita degli Studi di Roma I, ''La Sapienza,'' Corso Vittorio Emanuele II, 244, 00186 Roma, Italy)

1989-01-01

The spectrum from Compton-scattered x rays is an inherently broad distribution. This distribution is the sum of several Gaussian-like distributions, which gives the sum its unique shape. The Gaussian-like distributions are the result of convoluting the so-called Compton profile, the spread in the scattered-x-ray energies due to the momentum distributions of the target electrons, with the detector response and the geometrical effects. The distribution is then further modified by the absorption within the sample. A formulation for both qualitatively and quantitatively determining the magnitude of the geometrical contributions is presented. This formulation is based on a recently devised approach to the scattering geometry [Hanson, Gigante, Meron, Phys. Rev. Lett. 61, 135 (1988)]. A methodology for determining the geometrical spread in the energy of the scattered x rays is presented. The results can be conveniently used to optimize scattering geometries for the reduction of the geometry-caused spread

A model-based approach of scatter dose contributions and efficiency of apron shielding for radiation protection in CT.

Science.gov (United States)

Weber, N; Monnin, P; Elandoy, C; Ding, S

2015-12-01

Given the contribution of scattered radiations to patient dose in CT, apron shielding is often used for radiation protection. In this study the efficiency of apron was assessed with a model-based approach of the contributions of the four scatter sources in CT, i.e. external scattered radiations from the tube and table, internal scatter from the patient and backscatter from the shielding. For this purpose, CTDI phantoms filled with thermoluminescent dosimeters were scanned without apron, and then with an apron at 0, 2.5 and 5 cm from the primary field. Scatter from the tube was measured separately in air. The scatter contributions were separated and mathematically modelled. The protective efficiency of the apron was low, only 1.5% in scatter dose reduction on average. The apron at 0 cm from the beam lowered the dose by 7.5% at the phantom bottom but increased the dose by 2% at the top (backscatter) and did not affect the centre. When the apron was placed at 2.5 or 5 cm, the results were intermediate to the one obtained with the shielding at 0 cm and without shielding. The apron effectiveness is finally limited to the small fraction of external scattered radiation. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Dynamical coupled-channel analysis at EBAC. (Excited Baryon Analysis Center)

International Nuclear Information System (INIS)

Lee, T.-S.H.; Thomas Jefferson National Accelerator Facility, Newport News, VA

2008-01-01

In this contribution, the author reports on the dynamical coupled-channels analysis being pursued at the Excited Baryon Analysis Center (EBAC) of Jefferson Laboratory. EBAC was established in January 2006. Its objective is to extract the parameters associated with the excited states (N*) of the nucleon from the world data of meson production reactions, and to also develop theoretical interpretations of the extracted N* parameters

Analysis of Baryon Angular Correlations with Pythia

CERN Document Server

Mccune, Amara

2017-01-01

Our current understanding of baryon production is encompassed in the framework of the Lund String Fragmentation Model, which is then encoded in the Monte Carlo event generator program Pythia. In proton-proton collisions, daughter particles of the same baryon number produce an anti-correlation in $\\Delta\\eta\\Delta\\varphi$ space in ALICE data, while Pythia programs predict a correlation. To understand this unusual effect, where it comes from, and where our models of baryon production go wrong, correlation functions were systematically generated with Pythia. Effects of energy scaling, color reconnection, and popcorn parameters were investigated.

Study of ψ(3770 decaying to baryon anti-baryon pairs

Directory of Open Access Journals (Sweden)

Li-Gang Xia

2016-05-01

Full Text Available To study the decays of ψ(3770 going to baryon anti-baryon pairs (BB¯, all available experiments of measuring the cross sections of e+e−→BB¯ at center-of-mass energy ranging from 3.0 GeV to 3.9 GeV are combined. To relate the baryon octets, a model based on the SU(3 flavor symmetry is used and the SU(3 breaking effects are also considered. Assuming the electric and magnetic form factors are equal (|GE|=|GM|, a global fit including the interference between the QED process and the resonant process is performed. The branching fraction of ψ(3770→BB¯ is determined to be (2.4±0.8±0.3×10−5, (1.7±0.6±0.1×10−5, (4.5±0.9±0.1×10−5, (4.5±0.9±0.1×10−5, (2.0±0.7±0.1×10−5, and (2.0±0.7±0.1×10−5 for B=p,Λ,Σ+,Σ0,Ξ− and Ξ0, respectively, where the first uncertainty is from the global fit and the second uncertainty is the systematic uncertainty due to the assumption |GE|=|GM|. They are at least one order of magnitude larger than a simple scaling of the branching fraction of J/ψ/ψ(3686→BB¯.

On the proton exchange contribution to electron-hydrogen atom elastic scattering

International Nuclear Information System (INIS)

Mignaco, J.A.; Tort, A.C.

1979-05-01

It is shown that the exchange contribution to the electron-proton potential Born term in elastic electron-hydrogen atom scattering arises as the non relativistic limit from the exchange of a proton between the two participant electrons - calculated from quantum electrodynamics including properly bound states (as solution of Bethe - Salpeter equation). (Author) [pt

A topological model for baryon production in jets

International Nuclear Information System (INIS)

Ellis, J.; Kowalski, H.

1988-01-01

We present a conceptual model for baryon production in jets, inspired by the Skyrme picture of baryons as topological defects in a chiral quark-antiquark condensate. High energy collisions produce ''hot'' partons which split perturbatively into showers of ''cool'' partons which hadronize non-perturbatively. We visualize each of these as corresponding to a connected domain with a common orientation of the chiral condensate. Topological defects, namely baryons, are formed when there are mismatches in the orientations of adjacent field domains, rather as cosmic strings or monopoles are formed in the early Universe. Our model gives a good qualitative description of various salient features of baryon production in jets, which previously could be described only with a large number of free parameters. In particular, we give a qualitative explanation of the high baryon production rate in Υ decays compared to the e + e - continuum. When combined with a perturbative QCD parton shower Monte Carlo it could become a basis for a fully-fledged fragmentation model. (orig.)

Search for the doubly charmed baryon at LHCb

CERN Document Server

Zhong, Liang

The doubly charmed baryon $\\Xi_{cc}^+$, containing two charm quarks, is a baryon predicted by the SU(4) quark model. Experimentally its existence has not been established yet. Many Quantum Chromodynamics (QCD) based theoretical models have predicted its properties with a mass in the range 3500-3700 MeV/$c^2$ and a lifetime in the range 110-250 fs. The experimental searches for the $\\Xi_{cc}^+$ baryon and the measurements of its properties can test these models directly, providing an important input for the understanding of the non-perturbative aspect of QCD. The SELEX collaboration claimed the observation of the $\\Xi_{cc}^+$ baryon in the $\\Xi_{cc}^+ \\to \\Lambda_{c}^+K^-\\pi^+$ decay in 2003. However, the measured lifetime was much shorter than theoretical predictions. Searches for the $\\Xi_{cc}^+$ baryon in the same decay mode by FOCUS, Belle and BaBar experiments failed to reproduce the results. This does not mean that the SELEX result is excluded, however, since production environments at these experi...

QCD string in the baryon

International Nuclear Information System (INIS)

Kalashnikova, Yu.S.; Nefediev, A.V.

1997-01-01

The QCD-motivated constituent string model is extended to consider the baryon. The system of three quarks propagating in the confining background field is studied in the Wilson loop approach, and the effective action is obtained. The resulting Lagrangian at large interquark distances corresponds to the Mercedes Benz string configuration. Assuming the quarks to be heavy enough to allow the adiabatic separation of quark and string junction motion and using the hyperspherical expansion for the quark subsystem we write out and solve the classical equation of motion for the junction. We quantize the motion of the junction and demonstrate that the account of these modes leads to the effective swelling of baryon in comparison with standard potential picture. The effects of finite gluonic correlation length which do not affect the excited states but appear to be substantial for the baryonic ground state, reducing the swelling considerably is discussed

Study of the diffractive production of baryon states and search for cryptoexotic baryons with hidden strangeness

International Nuclear Information System (INIS)

Balatz, M.Ya.; Belyaev, I.M.; Dorofeev, V.A.

1993-01-01

The reactions of baryon diffractive production p + N → (pK + K - ) + N, p + N → (pφ) + N, p + N → [Λ(1520)K + ] + N and p + N → [Σ(1385) 0 K + ] + N in the 70 GeV proton beam were studied. Very sensitive upper limits for the production cross sections of heavy narrow cryptoexotic baryon resonances with hidden strangeness were obtained

Intriguing aspects in baryon production at relativistic heavy-ion collider

Indian Academy of Sciences (India)

nucleus collisions at RHIC. Outstanding physics issues include the mechanism for baryon–anti-baryon production from thermally equilibrated partons, the dynamics of baryon number transport and the evolution dynamics of baryons during ...

Exotic baryon resonances. Modern status. Possibilities to search and investigate

International Nuclear Information System (INIS)

Bagdasaryan, L.S.; Galumyan, P.I.; Grigoryan, A.A.; Kazaryan, S.P.; Khachatryan, G.N.; Oganesyan, A.G.; Vartapetyan, H.H.

1985-01-01

A possibility to investigate the exotic baryon resonances with qqqqq quark composition, in the systems pπ + π + , Λπ - π - , Σ - π - , etc. possessing exotic quantum numbers of isospin is considered. The most favourable reactions and kinematical regions where an effective search for the exotic baryons is possible are grounded. The contribution of the background subprocesses to the investigated systems is analyzed in various reactions and momenta configurations of the particles. The analysis shows that the search for the I=5/2 resonances in the system pπ + π + (Δ ++ π + ) is more reasonable in the π + p-interaction process, this system carrying the main portion of momentum in the lab. system. The exotic hyperons with S=-1 srangeness and I=2 isospin are to be searched in the fast-flying systems Λπ - π - (Σ* - (1385)π - ) and Σ - π - produced in the reactions on the K - beams. The cross sections of the production of the E 55 -baryon (J p =5/2 + , I=5/2) in the π + p → E 55 +++ π- and π + p → E 55 +++ x processes are theoretically estimated. The estimations show that in the experiments with the OMEGA spectometer at CERN one can get a substantial increase in the statistics as compared to that available, thus providing a detailed analysis of the pπ + π + system on the high confidence level. The question of investigation of the exotic baryon Regge trajectories in the processes of the inclusive production of ordinary (nonexotic) Δ ++ (1232), Σ* + (1385)- and Σ + -resonances in the π - -beam fragmentation region is also considered

Gauge theory for baryon and lepton numbers with leptoquarks.

Science.gov (United States)

Duerr, Michael; Fileviez Pérez, Pavel; Wise, Mark B

2013-06-07

Models where the baryon (B) and lepton (L) numbers are local gauge symmetries that are spontaneously broken at a low scale are revisited. We find new extensions of the standard model which predict the existence of fermions that carry both baryon and lepton numbers (i.e., leptoquarks). The local baryonic and leptonic symmetries can be broken at a scale close to the electroweak scale and we do not need to postulate the existence of a large desert to satisfy the experimental constraints on baryon number violating processes like proton decay.

Aharonov–Bohm protection of black hole's baryon/skyrmion hair

Directory of Open Access Journals (Sweden)

Gia Dvali

2017-05-01

Full Text Available The baryon/skyrmion correspondence implies that the baryon number is encoded into a topological surface integral. Under certain conditions that we clarify, this surface integral can be measured by an asymptotic observer in form of an Aharonov–Bohm phase-shift in an experiment in which the skyrmion passes through a loop of a probe string. In such a setup the baryon/skyrmion number must be respected by black holes, despite the fact that it produces no long-range classical field. If initially swallowed by a black hole, the baryon number must resurface in form of a classical skyrmion hair, after the black hole evaporates below a certain critical size. Needless to say, the respect of the baryon number by black holes is expected to have potentially-interesting astrophysical consequences.

Estimation of scattering contribution in the calibration of neutron devices with radionuclide sources in rooms of different sizes

Directory of Open Access Journals (Sweden)

Khabaz Rahim

2015-01-01

Full Text Available Calibrations of neutron devices used in area monitoring are often performed by radionuclide neutron sources. Device readings increase due to neutrons scattered by the surroundings and the air. The influence of said scattering effects have been investigated in this paper by performing Monte Carlo simulations for ten different radionuclide neutron sources inside several sizes of concrete wall spherical rooms (Rsp = 200 to 1500 cm. In order to obtain the parameters that relate the additional contribution from scattered neutrons, calculations using a polynomial fit model were evaluated. Obtained results show that the contribution of scattering is roughly independent of the geometric shape of the calibration room. The parameter that relates the room-return scattering has been fitted in terms of the spherical room radius, so as to reasonably accurately estimate the scattering value for each radionuclide neutron source in any geometry of the calibration room.

Baryonic dark matter and Machos

International Nuclear Information System (INIS)

Griest, K.

2000-01-01

A brief description of the status of baryons in the Universe is given, along with recent results from the MACHO collaboration and their meaning. A dark matter halo consisting of baryons in the form of Machos is ruled out, leaving an elementary particle as the prime candidate for the dark matter. The observed microlensing events may make up around 20% of the dark matter in the Milky Way, or may indicate an otherwise undetected component of the Large Magellanic Cloud

Study of the diffractive production of baryon states and search for cryptoexotic baryons with hidden strangeness

Energy Technology Data Exchange (ETDEWEB)

Balatz, M.Ya.; Belyaev, I.M.; Dorofeev, V.A.; Dzyubenko, G.B.; Filimonov, I.M.; Frolov, S.V.; Golovkin, S.V.; Grishkin, Yu.L.; Gritzuk, M.V.; Jilin, A.V.; Kamenskii, A.D.; Kliger, G.K.; Kolganov, V.Z.; Konstantinov, A.S.; Korchagin, Yu.V.; Kozhevnikov, A.P.; Kubarovskii, V.P.; Kulman, N.Yu.; Kulyavtsev, A.I.; Kurshetsov, V.F.; Kushnirenko, A.E.; Lakaev, V.S.; Landsberg, L.G.; Lebedev, A.A.; Lomkatzi, G.S.; Molchanov, V.V.; Mukhin, V.A.; Nilov, A.F.; Novoghilov, Yu.B.; Prutskoi, V.A.; Sitnikov, A.I.; Smolyankin, V.T.; Solyanik, V.I.; Vavilov, D.V.; Victorov, V.A.; Vishnyakov, V.E. (Inst. for High Energy Physics, Protvino (Russian Federation) Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation) Moscow State Univ. (Russian Federation)); SPHINX Collaboration

1994-02-01

The reactions of baryon diffractive production p + N [yields] (pK[sup +] K[sup -]) + N, p + N [yields] (p[Phi]) + N, p + N [yields] [Lambda](1520) K[sup +] + N and p + N [yields] [Sigma](1385) K[sup +] + N in the 70 GeV proton beam were studied. Very sensitive upper limits for the production cross sections of heavy narrow cryptoexotic baryon resonances with hidden strangeness were obtained. (orig.)

The Compressed Baryonic Matter experiment

Directory of Open Access Journals (Sweden)

Seddiki Sélim

2014-04-01

Full Text Available The Compressed Baryonic Matter (CBM experiment is a next-generation fixed-target detector which will operate at the future Facility for Antiproton and Ion Research (FAIR in Darmstadt. The goal of this experiment is to explore the QCD phase diagram in the region of high net baryon densities using high-energy nucleus-nucleus collisions. Its research program includes the study of the equation-of-state of nuclear matter at high baryon densities, the search for the deconfinement and chiral phase transitions and the search for the QCD critical point. The CBM detector is designed to measure both bulk observables with a large acceptance and rare diagnostic probes such as charm particles, multi-strange hyperons, and low mass vector mesons in their di-leptonic decay. The physics program of CBM will be summarized, followed by an overview of the detector concept, a selection of the expected physics performance, and the status of preparation of the experiment.

Search for CP violation in baryon decays at LHCb

CERN Multimedia

CERN. Geneva

2016-01-01

The phenomenon of CP violation has been observed in the K- and B-meson systems, but not yet with any baryonic particle. We report on searches for CP violation in baryon decays at LHCb using Run I data. We find evidence for CP violation in Lambda0b -> p pi- pi+ pi- decays with a statistical significance corresponding to 3.3 standard deviations, including systematic uncertainties. This represents the first evidence of CP violation in the baryon sector. An overview of other recent results of baryon decays will be presented, along with some highlights of the charmless B-decay programme.

Production of the superheavy baryon Λ{sub c} {sub anti} {sub c}{sup *}(4209) in kaon-induced reaction

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiao-Yun [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); University of Chinese Academy of Sciences, Beijing (China); Institute of Modern Physics of CAS and Lanzhou University, Research Center for Hadron and CSR Physics, Lanzhou (China); Chen, Xu-Rong [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Institute of Modern Physics of CAS and Lanzhou University, Research Center for Hadron and CSR Physics, Lanzhou (China)

2015-07-15

The production of superheavy Λ{sub c} {sub anti} {sub c}{sup *}(4209) baryon in the K{sup -}p → η{sub c}Λ process via s-channel is investigated with an effective Lagrangian approach and the isobar model. Moreover, the background from the K{sup -}p → η{sub c}Λ reaction through the t-channel with K* exchange and u-channel with nucleon exchange are also considered. The numerical results indicate it is feasible to search for the superheavy Λ{sub c} {sub anti} {sub c}{sup *}(4209) via K{sup -}p scattering. The relevant calculations not only shed light on the further experiment of searching for the Λ{sub c} {sub anti} {sub c}{sup *}(4209) through kaon-induced reaction, but also enable us to have a better understanding of the exotic baryons. (orig.)

Electromagnetic properties of baryons

Energy Technology Data Exchange (ETDEWEB)

Haupt, C.

2006-07-01

the charge radius and magnetic moment operators. The charge radii and magnetic moments of the baryon octet are thus obtained. A study on the dependence of the contributions of quark spins and orbital angular momenta to the total magnetic moment on the constituent quark mass reveals that at a quark mass of 330 MeV roughly ninety percent are due to spin. The calculated values for the hyperon radii and magnetic moments of selected excited states as well as mostly the baryon decuplet are predictions. (orig.)

Baryon-to-dark matter ratio from random angular fields

International Nuclear Information System (INIS)

McDonald, John

2013-01-01

We consider the baryon-to-dark matter ratio in models where the dark matter and baryon densities depend on angular fields θ d and θ b according to ρ d ∝θ d α and ρ b ∝θ b β , with all values of θ d and θ b being equally probable in a given randomly-selected domain. Under the assumption that anthropic selection depends primarily on the baryon density in galaxies at spherical collapse, we show that the probability density function for the baryon-to-dark matter ratio r = Ω B /Ω DM is purely statistical in nature and is independent of anthropic selection. We compute the probability density function for r as a function of α and β and show that the observed value of the baryon-to-dark matter ratio, r ≈ 1/5, is natural in this framework

Baryon symmetric big-bang cosmology

Energy Technology Data Exchange (ETDEWEB)

Stecker, F.W.

1978-04-01

The framework of baryon-symmetric big-bang cosmology offers the greatest potential for deducing the evolution of the universe as a consequence of physical laws and processes with the minimum number of arbitrary assumptions as to initial conditions in the big-bang. In addition, it offers the possibility of explaining the photon-baryon ratio in the universe and how galaxies and galaxy clusters are formed, and also provides the only acceptable explanation at present for the origin of the cosmic gamma ray background radiation.

Baryon symmetric big-bang cosmology

International Nuclear Information System (INIS)

Stecker, F.W.

1978-04-01

The framework of baryon-symmetric big-bang cosmology offers the greatest potential for deducing the evolution of the universe as a consequence of physical laws and processes with the minimum number of arbitrary assumptions as to initial conditions in the big-bang. In addition, it offers the possibility of explaining the photon-baryon ratio in the universe and how galaxies and galaxy clusters are formed, and also provides the only acceptable explanation at present for the origin of the cosmic gamma ray background radiation

Effect of Δ-isobar excitation on spin-dependent observables of elastic nucleon-deuteron scattering

International Nuclear Information System (INIS)

Nemoto, S.; Oryu, S.; Chmielewski, K.; Sauer, P.U.

2000-01-01

Δ-isobar excitation in the nuclear medium yields an effective three-nucleon force. A coupled-channel formulation with Δ-isobar excitation developed previously is used. The three-particle scattering equations are solved by a separable expansion of the two-baryon transition matrix for elastic nucleon-deuteron scattering. The effect of Δ-isobar excitation on the spin-dependent observables is studied at energies above 50 MeV nucleon lab energy. (author)

Baryon spectroscopy. Recent results from the CBELSA/TAPS experiment at ELSA

Energy Technology Data Exchange (ETDEWEB)

Hartmann, Jan [HISKP, Universitaet Bonn (Germany); Collaboration: CBELSA/TAPS-Collaboration

2016-07-01

One of the remaining challenges within the standard model is to gain a good understanding of QCD in the non-perturbative regime. A key step towards this aim is baryon spectroscopy, investigating the spectrum and the properties of baryon resonances. To gain access to resonances with small πN partial width, photoproduction experiments provide essential information. Partial wave analyses need to be performed to extract the contributing resonances. Here, a complete experiment is required to unambiguously determine the contributing amplitudes. This involves the measurement of carefully chosen single and double polarization observables. The CBELSA/TAPS experiment with a longitudinally or transversely polarized target and an energy tagged, linearly or circularly polarized photon beam allows the measurement of a large set of polarization observables. Due to its good energy resolution, high detection efficiency for photons, and the nearly complete solid angle coverage it is ideally suited for the measurement of photoproduction of neutral mesons decaying into photons. In this talk recent results for various double polarization observables in single- and multi-meson final states are presented, and their impact on the partial wave analysis are discussed.

Multi baryons with flavors in the Skyrme model

Energy Technology Data Exchange (ETDEWEB)

Schat, Carlos L. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Scoccola, Norberto N. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. of Physics

1999-07-01

We investigate the possible existence of multi baryons with heavy flavor quantum numbers using the bound state approach to the topological soliton model and the recently proposed approximation for multi skyrmion fields based on rational maps. We use an effective interaction Lagrangian which consistently incorporates both chiral symmetry and the heavy quark symmetry including the corrections up to order {omicron}(1/m{sub Q}). The model predicts some narrow heavy flavored multi baryon states with baryon number four and seven. (author)

Multi baryons with flavors in the Skyrme model

International Nuclear Information System (INIS)

Schat, Carlos L.; Scoccola, Norberto N.

1999-07-01

We investigate the possible existence of multi baryons with heavy flavor quantum numbers using the bound state approach to the topological soliton model and the recently proposed approximation for multi skyrmion fields based on rational maps. We use an effective interaction Lagrangian which consistently incorporates both chiral symmetry and the heavy quark symmetry including the corrections up to order ο(1/m Q ). The model predicts some narrow heavy flavored multi baryon states with baryon number four and seven. (author)

Determination of baryon and baryonic resonance masses from QCD sum rules. Strange baryons

International Nuclear Information System (INIS)

Belyaev, V.M.; Ioffe, B.L.

1982-01-01

The mass differences in baryonic octet Jsup(P)=1/2sup(+), decuplet Jsup(P)=3/2sup(+) and in octet Jsup(P)=3/2sup(-) are calculated basing on the QCD sum rules. The mass differences are expressed through two QCD parameters: the strange current qUark mass and the value of the quark condensate. At the properly chosen values of these parameters all of the mass differences are in a good agreement with experiment

Search for a narrow baryonic state decaying to pK{sup 0}{sub S} and anti pK{sup 0}{sub S} in deep inelastic scattering at HERA

Energy Technology Data Exchange (ETDEWEB)

Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max-Planck-Institute for Physics, Munich (Germany); Abt, I. [Max-Planck-Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science; Collaboration: ZEUS Collaboration; and others

2016-06-15

A search for a narrow baryonic state in the pK{sup 0}{sub S} and anti pK{sup 0}{sub S} system has been performed in ep collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb{sup -1} taken in 2003-2007. The search was performed with deep inelastic scattering events at an ep centre-of-mass energy of 318 GeV for exchanged photon virtuality, Q{sup 2}, between 20 and 100 GeV{sup 2}. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb{sup -1} taken in 1996-2000, no resonance peak was found in the p(anti p)K{sup 0}{sub S} invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.

A simple property of the contribution of double scattered radiation to the lidar returnes from homogeneous fogs

International Nuclear Information System (INIS)

Bruscaglioni, P.

1979-01-01

By using the formulas presented in a previous paper for the calculation of the ratio D/S between the contributions of doubly scattered and singly scattered radiation to lidar returns from homogeneous fogs, it is shown that the ratio D/S is proportional to the lidar range, indipendently from the particular model of fog, i.e. from the assumed phase scattering function

Baryons and ladders

International Nuclear Information System (INIS)

Ball, R.D.

1990-01-01

By formal manipulation of the QCD functional integral we arrive at a relativistic low energy effective theory of non-local color singlet mesons and baryons, which at tree level sums up ladders of effective glue exchange between constituent quarks. (orig.)

QCD at Zero Baryon Density and the Polyakov Loop Paradox

CERN Document Server

Kratochvila, S; Forcrand, Ph. de

2006-01-01

We compare the grand canonical partition function at fixed chemical potential mu with the canonical partition function at fixed baryon number B, formally and by numerical simulations at mu=0 and B=0 with four flavours of staggered quarks. We verify that the free energy densities are equal in the thermodynamic limit, and show that they can be well described by the hadron resonance gas at T T_c. Small differences between the two ensembles, for thermodynamic observables characterising the deconfinement phase transition, vanish with increasing lattice size. These differences are solely caused by contributions of non-zero baryon density sectors, which are exponentially suppressed with increasing volume. The Polyakov loop shows a different behaviour: for all temperatures and volumes, its expectation value is exactly zero in the canonical formulation, whereas it is always non-zero in the commonly used grand-canonical formulation. We clarify this paradoxical difference, and show that the non-vanishing Polyakov loop e...

Baryon symmetric big bang cosmology

International Nuclear Information System (INIS)

Stecker, F.W.

1978-01-01

It is stated that the framework of baryon symmetric big bang (BSBB) cosmology offers our greatest potential for deducting the evolution of the Universe because its physical laws and processes have the minimum number of arbitrary assumptions about initial conditions in the big-bang. In addition, it offers the possibility of explaining the photon-baryon ratio in the Universe and how galaxies and galaxy clusters are formed. BSBB cosmology also provides the only acceptable explanation at present for the origin of the cosmic γ-ray background radiation. (author)

Theoretical status of baryon magnetic moments

Science.gov (United States)

Franklin, Jerrold

1989-05-01

This talk given at the Eighth International Symposium on High-Energy Spin Physics in Minneapolis, Minnesota (September 12-17, 1988), is a short summary of theoretical results for baryon magnetic moments. Results from the static bag model and pion exchange effects are summarized and compared with experimental data. A list of references for various models and properties effecting the baryon magnetic moments is given at the end of the article. (AIP)

Theoretical status of baryon magnetic moments

International Nuclear Information System (INIS)

Franklin, J.

1989-01-01

This talk given at the Eighth International Symposium on High-Energy Spin Physics in Minneapolis, Minnesota (September 12--17, 1988), is a short summary of theoretical results for baryon magnetic moments. Results from the static bag model and pion exchange effects are summarized and compared with experimental data. A list of references for various models and properties effecting the baryon magnetic moments is given at the end of the article

Magnetic moments of the baryons: An experimental review

International Nuclear Information System (INIS)

Lach, J.

1990-11-01

Measurements of baryon magnetic moments have provided important insights into the composition of baryons as well as important constraints for model builders. These measurements show that a simple quark model describes most of the salient features. However, the significant discrepancies have raised fundamental questions about baryon structure and produced a steady stream of theoretical papers. I would like to briefly review the technology for making these measurements, the current state of the measurements, and the near term prospects for improvements. 14 refs., 5 figs., 1 tab

Dark matter, baryon asymmetry, and spontaneous B and L breaking

International Nuclear Information System (INIS)

Dulaney, Timothy R.; Wise, Mark B.; Perez, Pavel Fileviez

2011-01-01

We investigate the dark matter and the cosmological baryon asymmetry in a simple theory where baryon (B) and lepton (L) number are local gauge symmetries that are spontaneously broken. In this model, the cold dark matter candidate is the lightest new field with baryon number and its stability is an automatic consequence of the gauge symmetry. Dark matter annihilation is either through a leptophobic gauge boson whose mass must be below a TeV or through the Higgs boson. Since the mass of the leptophobic gauge boson has to be below the TeV scale, one finds that in the first scenario there is a lower bound on the elastic cross section of about 5x10 -46 cm 2 . Even though baryon number is gauged and not spontaneously broken until the weak scale, a cosmologically acceptable baryon excess is possible. There can be a tension between achieving both the measured baryon excess and the dark matter density.

Baryon resonances in pion- and photon-induced hadronic reactions

International Nuclear Information System (INIS)

Roenchen, Deborah

2014-01-01

The aim of the present work is the analysis of the baryon spectrum in the medium-energy regime. At those energies, a perturbative treatment of Quantum Chromodynamics, that is feasible in the high-energy regime, is not possible. Chiral perturbation theory, the low-energy effective theory of the strong interaction, is limited to the lowest excited states and does not allow to analyze the complete resonance region. For the latter purpose, dynamical coupled-channel approaches provide an especially suited framework. In the present study, we apply the Juelich model, a dynamical coupled-channel model developed over the years, to analyze pion- and photon-induced hadronic reactions in a combined approach. In the Juelich model, the interaction of the mesons and baryons is built of t- and u-channel exchange diagrams based on an effective Lagrangian. Genuine resonances are included as s-channel states. The scattering potential is unitarized in a Lippmann-Schwinger-type equation. Analyticity is preserved, which is a prerequisite for a reliable extraction of resonance parameters in terms of pole positions and residues in the complex energy plane. Upon giving an introduction to the subject in Chap. 1 and showing selected results in Chap. 2, we will describe the simultaneous analysis of elastic πN scattering and the reactions π - p → ηn, K 0 Λ, K + Σ - , K 0 Σ 0 and π + p→K + Σ + within the Juelich framework in Chap. 3. The free parameters of the model are adjusted to the GWU/SAID analysis of elastic πN scattering and, in case of the inelastic reactions, to experimental data. Partial waves up to J=9/2 are included and we consider the world data set from threshold up to E∝2.3 GeV. We show our fit results compared to differential and total cross sections, to polarizations and to measurements of the spin-rotation parameter. Finally, we present the results of a pole search in the complex energy plane of the scattering amplitude and discuss the extracted resonance

The origin of baryon number and related problems

International Nuclear Information System (INIS)

Schramm, D.N.; Turner, M.S.

1980-01-01

The possibility of cosmological baryon production, as motivated by grand unification, is discussed. It is postulated that the application of grand unified theories of particle interactions may explain the origin of baryons in the universe. (C.F.)

On gauged Baryon and Lepton numbers

International Nuclear Information System (INIS)

Rajpoot, S.

1990-01-01

The observation that Baryon number and Lepton number are conserved in nature provides strong motivation for associating gauge symmetries to these conserved numbers. This endeavor requires that the gauge group of electroweak interactions be extended from SU(2) L X U(1) Y to SU(2) L X U(1) R X U(1) Lepton where U(1) R couples only to the right-handed quarks and leptons. If it furthur postulated that right-handed currents exist on par with the left-handed ones, then the full electroweak symmetry is SU(2) L X SU(2) R X U(1) Baryon X U(1) Lepton . The SU(2) L X SU(2) R X U(1) Baryon X U(1) Lepton model is described in some detail. The triangle anomalies of the three families of quarks and leptons in the model are cancelled invoking leptoquark matter which is new fermionic matter that carries baryon as well as lepton numbers. In addition to the standard neutral boson (Z degree), the theory predicts two neutral gauge bosons with mass lower bounds of 120 GeV and 210 GeV which makes these particles prospective candidates for production at LEP, the TEVATRON and the SSC

Determination of the average lifetime of b-baryons

International Nuclear Information System (INIS)

Abreu, P.; Adam, W.

1996-01-01

The average lifetime of b-baryons has been studied using 3.10 6 hadronic Z 0 decays collected by the DELPHI detector at LEP. Three methods have been used, based on the measurement of different observables: the proper decay time distribution of 206 vertices reconstructed with a Λ, a lepton and an oppositely charged pion; the impact parameter distribution of 441 muons with high transverse momentum accompanied by a Λ in the same jet; and the proper decay time distribution of 125 Λ c -lepton decay vertices with the Λ c exclusively reconstructed through its pKπ, pK 0 and Λ3π decay modes. The combined result is: τ(b-baryon)=(1.254 +0.121 -0.109 (stat) ±0.04(syst) +0.03 -0.05 (syst)) ps where the first systematic error is due to experimental uncertainties and the second to the uncertainties in the modelling of the b-baryon production and semi-leptonic decay. Including the measurement recently published by DELPHI based on a sample of proton-muon vertices, the average b-baryon lifetime is: τ(b-baryon)=(1.255 +0.115 -0.102 (stat) ±0.05) ps. (orig.)

Brane-induced Skyrmion on S3: Baryonic matter in holographic QCD

International Nuclear Information System (INIS)

Nawa, Kanabu; Suganuma, Hideo; Kojo, Toru

2009-01-01

We study baryonic matter in holographic QCD with D4/D8/D8 multi-D brane system in type IIA superstring theory. The baryon is described as the 'brane-induced Skyrmion', which is a topologically nontrivial chiral soliton in the four-dimensional meson effective action induced by holographic QCD. We employ the ''truncated-resonance model'' approach for the baryon analysis, including pion and ρ meson fields below the ultraviolet cutoff scale M KK ∼1 GeV, to keep the holographic duality with QCD. We describe the baryonic matter in large N c as single brane-induced Skyrmion on the three-dimensional closed manifold S 3 with finite radius R. The interactions between baryons are simulated by the curvature of the closed manifold S 3 , and the decrease of the size of S 3 represents the increase of the total baryon-number density in the medium in this modeling. We investigate the energy density, the field configuration, the mass and the root-mean-square radius of single baryon on S 3 as the function of its radius R. We find a new picture of 'pion dominance' near the critical density in the baryonic matter, where all the (axial) vector meson fields disappear and only the pion fields survive. We also find the swelling phenomena of the baryons as the precursor of the deconfinement, and propose the mechanism of the swelling in the general context of QCD. The properties of the deconfinement and the chiral symmetry restoration in the baryonic matter are examined by taking the proper order parameters. We also compare our truncated-resonance model with another instanton description of the baryon in holographic QCD, considering the role of cutoff scale M KK .

Strong coupling QCD at finite baryon-number density

International Nuclear Information System (INIS)

Karsch, F.; Muetter, K.H.

1989-01-01

We present a new representation of the partition function for strong-coupling QCD which is suitable also for finite baryon-number-density simulations. This enables us to study the phase structure in the canonical formulation (with fixed baryon number B) as well as the grand canonical one (with fixed chemical potential μ). We find a clear signal for a first-order chiral phase transition at μ c a=0.63. The critical baryon-number density n c a 3 =0.045 is only slightly higher than the density of nuclear matter. (orig.)

Baryon number transfer in hadronic interactions

International Nuclear Information System (INIS)

Arakelyan, G.H.; Capella, A.; Kaidalov, A.B.; Shabelski, Yu.M.

2002-01-01

The process of baryon number transfer due to string junction propagation in rapidity space is analyzed. It has a significant effect on the net baryon production in pp collisions at mid-rapidities and an even larger effect in the forward hemisphere in the cases of πp and γp interactions. The results of numerical calculations in the framework of the quark-gluon string model are in reasonable agreement with the data. (orig.)

Hadronic light-by-light scattering contribution to the muon g - 2 on the lattice

Science.gov (United States)

Asmussen, Nils; Gérardin, Antoine; Green, Jeremy; Gryniuk, Oleksii; von Hippel, Georg; Meyer, Harvey B.; Nyffeler, Andreas; Pascalutsa, Vladimir; Wittig, Hartmut

2018-05-01

We briefly review several activities at Mainz related to hadronic light-by-light scattering (HLbL) using lattice QCD. First we present a position-space approach to the HLbL contribution in the muon g̅2, where we focus on exploratory studies of the pion-pole contribution in a simple model and the lepton loop in QED in the continuum and in infinite volume. The second part describes a lattice calculation of the double-virtual pion transition form factor Fπ0γ*γ* (q21; q21) in the spacelike region with photon virtualities up to 1.5 GeV2 which paves the way for a lattice calculation of the pion-pole contribution to HLbL. The third topic involves HLbL forward scattering amplitudes calculated in lattice QCD which can be described, using dispersion relations (HLbL sum rules), by γ*γ* → hadrons fusion cross sections and then compared with phenomenological models.

Heavy baryons in the relativistic quark model

International Nuclear Information System (INIS)

Ebert, D.; Faustov, R.N.; Galkin, V.O.; Martynenko, A.P.; Saleev, V.A.

1996-07-01

In the framework of the relativistic quasipotential quark model the mass spectrum of baryons with two heavy quarks is calculated. The quasipotentials for interactions of two quarks and of a quark with a scalar and axial vector diquark are evaluated. The bound state masses of baryons with J P =1/2 + , 3/2 + are computed. (orig.)

Strange baryon production in Z hadronic decays

CERN Document Server

Abreu, P; Adye, T; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Allport, P P; Almehed, S; Alvsvaag, S J; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Anykeyev, V B; Apel, W D; Arnoud, Y; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barate, R; Bardin, Dimitri Yuri; Barker, G J; Baroncelli, A; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bocci, V; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brunet, J M; Brückman, P; Bugge, L; Buran, T; Buys, A; Bärring, O; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carrilho, P; Carroll, L; Caso, Carlo; Cassio, V; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chikilev, O G; Chliapnikov, P V; Chochula, P; Chorowicz, V; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; D'Almagne, B; Da Silva, W; Dahl-Jensen, Erik; Dahm, J; Dam, M; Damgaard, G; Daum, A; Dauncey, P D; Davenport, Martyn; De Angelis, A; De Boeck, H; De Brabandere, S; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Defoix, C; Della Ricca, G; Delpierre, P A; Demaria, N; Di Ciaccio, Lucia; Dijkstra, H; Djama, F; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Dupont, F; Dönszelmann, M; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Filippas-Tassos, A; Firestone, A; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Föth, H; Fürstenau, H; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gillespie, D; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Gracco, Valerio; Grard, F; Graziani, E; Grosdidier, G; Gunnarsson, P; Guy, J; Guz, Yu; Górski, M; Günther, M; Haedinger, U; Hahn, F; Hahn, M; Hahn, S; Haider, S; Hajduk, Z; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Ioannou, P; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Joram, Christian; Juillot, P; Jönsson, L B; Jönsson, P E; Kaiser, M; Kalmus, George Ernest; Kapusta, F; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Królikowski, J; Kubinec, P; Kucewicz, W; Kurvinen, K L; Kuznetsov, O; Köhne, J H; Köne, B; La Vaissière, C de; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lokajícek, M; Loken, J G; Loukas, D; Lutz, P; Lyons, L; López, J M; López-Aguera, M A; López-Fernandez, A; Lörstad, B; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martí i García, S; Martínez-Rivero, C; Martínez-Vidal, F; Maréchal, B; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Meroni, C; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Monge, M R; Morettini, P; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Mönig, K; Møller, R; Müller, H; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Némécek, S; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Pape, L; Parodi, F; Passeri, A; Pegoraro, M; Pennanen, J; Peralta, L; Pernegger, H; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ruiz, A; Rídky, J; Rückstuhl, W; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sannino, M; Schneider, H; Schyns, M A E; Sciolla, G; Scuri, F; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stepaniak, K; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Stäck, H; Szczekowski, M; Szeptycka, M; Sánchez, J; Tabarelli de Fatis, T; Tavernet, J P; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tuuva, T; Tyapkin, I A; Tyndel, M; Tzamarias, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van Doninck, W K; Van Eldik, J; Van der Velde, C; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Voutilainen, M; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Wehr, A; Weierstall, M; Weilhammer, Peter; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Wormser, G; Woschnagg, K; Yip, K; Yu, L; Yushchenko, O P; Zach, F; Zacharatou-Jarlskog, C; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zhigunov, V P; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G; de Boer, Wim; van Apeldoorn, G W; van Dam, P; Åsman, B; Österberg, K; Überschär, B; Überschär, S

1995-01-01

A study of the production of strange octet and decuplet baryons in hadronic decays of the Z recorded by the DELPHI detector at LEP is presented. This includes the first measurement of the \\Sigma^\\pm average multiplicity. The total and differential cross sections, the event topology and the baryon-antibaryon correlations are compared with current hadronization models.

Baryonic Dark Matter

OpenAIRE

De Paolis, F.; Jetzer, Ph.; Ingrosso, G.; Roncadelli, M.

1997-01-01

Reasons supporting the idea that most of the dark matter in galaxies and clusters of galaxies is baryonic are discussed. Moreover, it is argued that most of the dark matter in galactic halos should be in the form of MACHOs and cold molecular clouds.

J/ψ -pair production at large momenta: Indications for double parton scatterings and large α$_s^5$ contributions

CERN Document Server

Lansberg, Jean-Philippe

2015-01-01

The recent observations of prompt J/psi-pair production by CMS at the LHC and by D0 at the Tevatron reveal the presence of different production mechanisms in different kinematical regions. We find out that next-to-leading-order single-parton-scattering contributions at alpha_s^5 dominate the yield at large transverse momenta of the pair. Our analysis further emphasises the importance of double-parton-scatterings --which are expected to dominate the yield at large rapidity differences-- at large invariant masses of the pair in the CMS acceptance. In addition, we provide the first exact --gauge-invariant and infrared-safe-- evaluation of a class of leading-P_T next-to-next-to-leading-order contributions, which are dominant in the region of large sub-leading transverse momenta, precisely where the colour-octet contributions can be non-negligible. Finally, we discuss the contribution from decays of excited charmonium states within both single- and double-parton scatterings and suggest measurements to distinguish ...

New paradigm for baryon and lepton number violation

International Nuclear Information System (INIS)

Fileviez Pérez, Pavel

2015-01-01

The possible discovery of proton decay, neutron–antineutron oscillation, neutrinoless double beta decay in low energy experiments, and exotic signals related to the violation of the baryon and lepton numbers at collider experiments will change our understanding of the conservation of fundamental symmetries in nature. In this review we discuss the rare processes due to the existence of baryon and lepton number violating interactions. The simplest grand unified theories and the neutrino mass generation mechanisms are discussed. The theories where the baryon and lepton numbers are defined as local gauge symmetries spontaneously broken at the low scale are discussed in detail. The simplest supersymmetric gauge theory which predicts the existence of lepton number violating processes at the low scale is investigated. The main goal of this review is to discuss the main implications of baryon and lepton number violation in physics beyond the Standard Model.

Quark interchange model of baryon interactions

Energy Technology Data Exchange (ETDEWEB)

Maslow, J.N.

1983-01-01

The strong interactions at low energy are traditionally described by meson field theories treating hadrons as point-like particles. Here a mesonic quark interchange model (QIM) is presented which takes into account the finite size of the baryons and the internal quark structure of hadrons. The model incorporates the basic quark-gluon coupling of quantum chromodynamics (QCD) and the MIT bag model for color confinement. Because the quark-gluon coupling constant is large and it is assumed that confinement excludes overlap of hadronic quark bags except at high momenta, a non-perturbative method of nuclear interactions is presented. The QIM allows for exchange of quark quantum numbers at the bag boundary between colliding hadrons mediated at short distances by a gluon exchange between two quarks within the hadronic interior. This generates, via a Fierz transformation, an effective space-like t channel exchange of color singlet (q anti-q) states that can be identified with the low lying meson multiplets. Thus, a one boson exchange (OBE) model is obtained that allows for comparison with traditional phenomenological models of nuclear scattering. Inclusion of strange quarks enables calculation of YN scattering. The NN and YN coupling constants and the nucleon form factors show good agreement with experimental values as do the deuteron low energy data and the NN low energy phase shifts. Thus, the QIM provides a simple model of strong interactions that is chirally invariant, includes confinement and allows for an OBE form of hadronic interaction at low energies and momentum transfers.

Quark interchange model of baryon interactions

International Nuclear Information System (INIS)

Maslow, J.N.

1983-01-01

The strong interactions at low energy are traditionally described by meson field theories treating hadrons as point-like particles. Here a mesonic quark interchange model (QIM) is presented which takes into account the finite size of the baryons and the internal quark structure of hadrons. The model incorporates the basic quark-gluon coupling of quantum chromodynamics (QCD) and the MIT bag model for color confinement. Because the quark-gluon coupling constant is large and it is assumed that confinement excludes overlap of hadronic quark bags except at high momenta, a non-perturbative method of nuclear interactions is presented. The QIM allows for exchange of quark quantum numbers at the bag boundary between colliding hadrons mediated at short distances by a gluon exchange between two quarks within the hadronic interior. This generates, via a Fierz transformation, an effective space-like t channel exchange of color singlet (q anti-q) states that can be identified with the low lying meson multiplets. Thus, a one boson exchange (OBE) model is obtained that allows for comparison with traditional phenomenological models of nuclear scattering. Inclusion of strange quarks enables calculation of YN scattering. The NN and YN coupling constants and the nucleon form factors show good agreement with experimental values as do the deuteron low energy data and the NN low energy phase shifts. Thus, the QIM provides a simple model of strong interactions that is chirally invariant, includes confinement and allows for an OBE form of hadronic interaction at low energies and momentum transfers

Isospin Splittings in the Light-Baryon Octet from Lattice QCD and QED

Science.gov (United States)

Borsanyi, Sz.; Dürr, S.; Fodor, Z.; Frison, J.; Hoelbling, C.; Katz, S. D.; Krieg, S.; Kurth, Th.; Lellouch, L.; Lippert, Th.; Portelli, A.; Ramos, A.; Sastre, A.; Szabo, K.; Budapest-Marseille-Wuppertal Collaboration

2013-12-01

While electromagnetic and up-down quark mass difference effects on octet baryon masses are very small, they have important consequences. The stability of the hydrogen atom against beta decay is a prominent example. Here, we include these effects by adding them to valence quarks in a lattice QCD calculation based on Nf=2+1 simulations with five lattice spacings down to 0.054 fm, lattice sizes up to 6 fm, and average up-down quark masses all the way down to their physical value. This allows us to gain control over all systematic errors, except for the one associated with neglecting electromagnetism in the sea. We compute the octet baryon isomultiplet mass splittings, as well as the individual contributions from electromagnetism and the up-down quark mass difference. Our results for the total splittings are in good agreement with experiment.

On the quark-mass dependence of baryon ground-state masses

International Nuclear Information System (INIS)

Semke, Alexander

2010-01-01

Baryon masses of the flavour SU(3) octet and decuplet baryons are calculated in the framework of the Chiral Perturbations Theory - the effective field theory of the strong interaction. The chiral extrapolation to the higher meson (quark) masses is carried out. The comparison with the recent results on the baryon masses from lattice calculations are presented. (orig.)

On the quark-mass dependence of baryon ground-state masses

Energy Technology Data Exchange (ETDEWEB)

Semke, Alexander

2010-02-17

Baryon masses of the flavour SU(3) octet and decuplet baryons are calculated in the framework of the Chiral Perturbations Theory - the effective field theory of the strong interaction. The chiral extrapolation to the higher meson (quark) masses is carried out. The comparison with the recent results on the baryon masses from lattice calculations are presented. (orig.)

Excited baryons

International Nuclear Information System (INIS)

Mukhopadhyay, N.C.

1986-01-01

The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for excited baryon research at CFBAF are suggested

Excited baryons

Energy Technology Data Exchange (ETDEWEB)

Mukhopadhyay, N.C.

1986-01-01

The status of the theory of the low-energy approach to hadron structure is reviewed briefly by surveying a few relevant models. A few examples of tests needed to sort out the predictions of different models pertaining to the quark-gluon structure of hadrons are discussed, and given the resulting physics objectives, a few experimental options for excited baryon research at CFBAF are suggested. (LEW)

Hadronic production of baryons containing two heavy quarks

International Nuclear Information System (INIS)

Berezhnoj, A.V.; Kiselev, V.V.; Likhoded, A.K.

1995-01-01

In the framework of the QCD perturbation theory, total and differential cross sections of the Ξ bc ' , Ξ bc ( * ) and Ξ cc ( * ) baryons production in gluon collisions are calculated in the leading order over α s for the doubly heavy (bc) and (cc) diquarks. At both small and large transverse momenta of baryons, a use of the mechanism of the heavy quark fragmentation into the heavy diquark is shown to underestimate the cross section values in comparison with the exact numerical calculations of a complete set of diagrams. The expected in Tevatron experiments yield of baryons with two heavy quarks is evaluated [ru

Examination of higher-order twist contributions in parity-violating deep-inelastic electron-deuteron scattering

International Nuclear Information System (INIS)

Mantry, Sonny; Ramsey-Musolf, Michael J.; Sacco, Gian Franco

2010-01-01

We show that parity-violating deep-inelastic scattering (PVDIS) of longitudinally polarized electrons from deuterium can in principle be a relatively clean probe of higher twist quark-quark correlations beyond the parton model. As first observed by Bjorken and Wolfenstein, the dominant contribution to the electron polarization asymmetry, proportional to the axial vector electron coupling, receives corrections at twist four from the matrix element of a single four-quark operator. We reformulate the Bjorken-Wolfenstein argument in a matter suitable for the interpretation of experiments planned at the Thomas Jefferson National Accelerator Facility (JLab). In particular, we observe that because the contribution of the relevant twist-four operator satisfies the Callan-Gross relation, the ratio of parity-violating longitudinal and transverse cross sections, R γZ , is identical to that for purely electromagnetic scattering, R γ , up to perturbative and power-suppressed contributions. This result simplifies the interpretation of the asymmetry in terms of other possible novel hadronic and electroweak contributions. We use the results of MIT Bag Model calculations to estimate contributions of the relevant twist-four operator to the leading term in the asymmetry as a function of Bjorken x and Q 2 . We compare these estimates with possible leading twist corrections from violation of charge symmetry in the parton distribution functions.

The good, the bad, and the baryon

International Nuclear Information System (INIS)

Ball, R.D.

1990-01-01

We describe the incorporation of baryons into an effective theory of QCD at low energies. The baryon is not a Skyrmion, rather it consists of three valence quarks bound by effective gluon exchanges, enveloped in a meson cloud, which may possibly take the form of a chiral soliton. Some of the physical implications of these results are also discussed. (orig.)

Spectroscopy of doubly charmed baryons from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Padmanath, M. [Univ. of Graz, Graz (Austria); Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Mathur, Nilmani [Tata Inst. of Fundamental Research, Mumbai (India); Peardon, Michael [Trinity College, Dublin (Ireland)

2015-05-06

This study presents the ground and excited state spectra of doubly charmed baryons from lattice QCD with dynamical quark fields. Calculations are performed on anisotropic lattices of size 16³ × 128, with inverse spacing in temporal direction a_t⁻¹=5.67(4) GeV and with a pion mass of about 390 MeV. A large set of baryonic operators that respect the symmetries of the lattice yet which retain a memory of their continuum analogues are used. These operators transform as irreducible representations of SU(3)_F symmetry for flavor, SU(4) symmetry for Dirac spins of quarks and O(3) for spatial symmetry. The distillation method is utilized to generate baryon correlation functions which are analyzed using the variational fitting method to extract excited states. The lattice spectra obtained have baryonic states with well-defined total spins up to 7/2 and the pattern of low-lying states does not support the diquark picture for doubly charmed baryons. On the contrary the calculated spectra are remarkably similar to the expectations from models with an SU(6)×O(3) symmetry. Various spin-dependent energy splittings between the extracted states are also evaluated.

Excited state mass spectra of singly charmed baryons

Energy Technology Data Exchange (ETDEWEB)

Shah, Zalak; Kumar Rai, Ajay [Sardar Vallabhbhai National Institute of Technology, Department of Applied Physics, Surat, Gujarat (India); Thakkar, Kaushal [GIDC Degree Engineering College, Department of Applied Sciences and Humanities, Abrama (India); Vinodkumar, P.C. [Sardar Patel University, Department of Physics, V.V. Nagar (India)

2016-10-15

Mass spectra of excited states of the singly charmed baryons are calculated using the hypercentral description of the three-body system. The baryons consist of a charm quark and light quarks (u, d and s) are studied in the framework of QCD motivated constituent quark model. The form of the confinement potential is hyper-Coloumb plus power potential with potential index ν, varying from 0.5 to 2.0. The first-order correction to the confinement potential is also incorporated in this approach. The radial as well as orbital excited state masses of Σ{sub c}{sup ++}, Σ{sub c}{sup +}, Σ{sub c}{sup 0}, Ξ{sub c}{sup +}, Ξ{sub c}{sup 0}, Λ{sub c}{sup +}, Ω{sub c}{sup 0} baryons, are reported in this paper. We have incorporated spin-spin, spin-orbit and tensor interactions perturbatively in the present study. The semi-electronic decay of Ω{sub c} and Ξ{sub c} are also calculated using the spectroscopic parameters of these baryons. The computed results are compared with other theoretical predictions as well as with the available experimental observations. We also construct the Regge trajectory in (n{sub r},M{sup 2}) and (J,M{sup 2}) planes for these baryons. (orig.)

CP asymmetries in Strange Baryon Decays

Science.gov (United States)

Bigi, I. I.; Kang, Xian-Wei; Li, Hai-Bo

2018-01-01

While indirect and direct CP violation (CPV) has been established in the decays of strange and beauty mesons, no CPV has yet been found for baryons. There are different paths to finding CP asymmetry in the decays of strange baryons; they are all highly non-trivial. The HyperCP Collaboration has probed CPV in the decays of single Ξ and Λ [1]. We discuss future lessons from {{{e}}}+{{{e}}}- collisions at BESIII/BEPCII: probing decays of pairs of strange baryons, namely Λ, Σ and Ξ. Realistic goals are to learn about non-perturbative QCD. One can hope to find CPV in the decays of strange baryons; one can also dream of finding the impact of New Dynamics. We point out that an important new era will start with the BESIII/BEPCII data accumulated by the end of 2018. This also supports new ideas to trigger {{J}}/{{\\psi }}\\to \\bar{{{Λ }}}{{Λ }} at the LHCb collaboration. Supported by National Science Foundation (PHY-1520966), National Natural Science Foundation of China (11335009, 11125525), Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1532257), the National Key Basic Research Program of China (2015CB856700), Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH003), XWK’s work is also supported by MOST (Taiwan) (104-2112-M-001-022)

Baryon electromagnetic form factors at BESIII

Directory of Open Access Journals (Sweden)

Dbeyssi Alaa

2017-01-01

Full Text Available Electromagnetic form factors are fundamental quantities which parameterize the electric and magnetic structure of hadrons. This contribution reports on the measurements of baryon electromagnetic form factors at the BESIII experiment in Beijing. The Beijing e+e− collider BEPCII is a double-ring symmetric collider running at √s between 2.0 and 4.6 GeV. Baryon electromagnetic form factors can be measured at BESIII in direct e+e−-annihilation and in initial state radiation processes. Based on the data collected by the BESIII detector at 12 center of mass energies between 2.23 and 3.67 GeV, the e+e− → p̄p cross section and the time-like proton form factor is measured. Preliminary results from the analysis of the initial state radiation process e+e− → p̄pγ using a data set of 7.408 fb−1 collected at center-of-mass energies between 3.773 and 4.6 GeV, are also presented. The cross section for e+e−→Λ¯Λ${e^ + }{e^ - } \\to \\bar \\Lambda \\Lambda $ is measured based on 40.5 pb−1 data collected at 4 energy points from the threshold up to 3.08 GeV. Preliminary results on the total cross section and the Λ effective form factor are shown. Ongoing analysis based on the high luminosity energy scan from 2015 and from radiative return at different √s are also described.

A Monte Carlo model to produce baryons in e+e- annihilation

International Nuclear Information System (INIS)

Meyer, T.

1981-08-01

A simple model is described extending the Field-Feynman model to baryon production in quark fragmentation. The model predicts baryon baryon correlations within jets and in opposite jets produced in electron-positron annihilation. Existing data is well described by the model. (orig.)

New predictions for generalized spin polarizabilities from heavy baryon chiral perturbation theory

International Nuclear Information System (INIS)

Chung-Wen Kao; Barbara Pasquini; Marc Vanderhaeghen

2004-01-01

We extract the next-to-next-to-leading order results for spin-flip generalized polarizabilities (GPs) of the nucleon from the spin-dependent amplitudes for virtual Compton scattering (VCS) at Ο(p 4 ) in heavy baryon chiral perturbation theory. At this order, no unknown low energy constants enter the theory, allowing us to make absolute predictions for all spin-flip GPs. Furthermore, by using constraint equations between the GPs due to nucleon crossing combined with charge conjugation symmetry of the VCS amplitudes, we get a next-to-next-to-next-to-leading order prediction for one of the GPs. We provide estimates for forthcoming double polarization experiments which allow to access these spin-flip GPs of the nucleon

Strangeness as a probe to baryon-rich QCD matter at NICA

Energy Technology Data Exchange (ETDEWEB)

Fukushima, Kenji [The University of Tokyo, Department of Physics, Bunkyo-ku, Tokyo (Japan)

2016-08-15

We elucidate a prospect of strangeness fluctuation measurements in the heavy-ion collision at NICA energies. The strangeness fluctuation is sensitive to quark deconfinement. At the same time strangeness has a strong correlation with the baryon number under the condition of vanishing net strangeness, which leads to an enhancement of Λ{sup 0}, Ξ{sup 0}, Ξ{sup -}, and K{sup +} at high baryon density. The baryon density is maximized around the NICA energies, and strangeness should be an ideal probe to investigate quark deconfinement phenomena of baryon-rich QCD matter created at NICA. We also utilize the hadron resonance gas model to estimate a mixed fluctuation of strangeness and baryon number. (orig.)

Masses and sigma terms of doubly charmed baryons up to O (p4) in manifestly Lorentz-invariant baryon chiral perturbation theory

Science.gov (United States)

Yao, De-Liang

2018-02-01

We calculate the masses and sigma terms of the doubly charmed baryons up to next-to-next-to-next-to-leading order [i.e., O (p4) ] in a covariant baryon chiral perturbation theory by using the extended-on-mass-shell renormalization scheme. Their expressions both in infinite and finite volumes are provided for chiral extrapolation in lattice QCD. As a first application, our chiral results of the masses are confronted with the existing lattice QCD data in the presence of finite-volume corrections. Up to O (p3) , all relevant low-energy constants can be well determined. As a consequence, we obtain the physical values for the masses of Ξc c and Ωc c baryons by extrapolating to the physical limit. Our determination of the Ξc c mass is consistent with the recent experimental value by LHCb Collaboration, however, larger than the one by SELEX Collaboration. In addition, we predict the pion-baryon and strangeness-baryon sigma terms, as well as the mass splitting between the Ξc c and Ωc c states. Their quark mass dependences are also discussed. The numerical procedure can be applied to the chiral results of O (p4) order, where more unknown constants are involved, when more data are available for unphysical pion masses.

Layers of deformed instantons in holographic baryonic matter

Energy Technology Data Exchange (ETDEWEB)

Preis, Florian [Institut für Theoretische Physik, Technische Universität Wien,1040 Vienna (Austria); Schmitt, Andreas [Mathematical Sciences and STAG Research Centre, University of Southampton,Southampton SO17 1BJ (United Kingdom)

2016-07-01

We discuss homogeneous baryonic matter in the decompactified limit of the Sakai-Sugimoto model, improving existing approximations based on flat-space instantons. We allow for an anisotropic deformation of the instantons in the holographic and spatial directions and for a density-dependent distribution of arbitrarily many instanton layers in the bulk. Within our approximation, the baryon onset turns out to be a second-order phase transition, at odds with nature, and there is no transition to quark matter at high densities, at odds with expectations from QCD. This changes when we impose certain constraints on the shape of single instantons, motivated by known features of holographic baryons in the vacuum. Then, a first-order baryon onset and chiral restoration at high density are possible, and at sufficiently large densities two instanton layers are formed dynamically. Our results are a further step towards describing realistic, strongly interacting matter over a large density regime within a single model, desirable for studies of compact stars.

The baryonic self similarity of dark matter

International Nuclear Information System (INIS)

Alard, C.

2014-01-01

The cosmological simulations indicates that dark matter halos have specific self-similar properties. However, the halo similarity is affected by the baryonic feedback. By using momentum-driven winds as a model to represent the baryon feedback, an equilibrium condition is derived which directly implies the emergence of a new type of similarity. The new self-similar solution has constant acceleration at a reference radius for both dark matter and baryons. This model receives strong support from the observations of galaxies. The new self-similar properties imply that the total acceleration at larger distances is scale-free, the transition between the dark matter and baryons dominated regime occurs at a constant acceleration, and the maximum amplitude of the velocity curve at larger distances is proportional to M 1/4 . These results demonstrate that this self-similar model is consistent with the basics of modified Newtonian dynamics (MOND) phenomenology. In agreement with the observations, the coincidence between the self-similar model and MOND breaks at the scale of clusters of galaxies. Some numerical experiments show that the behavior of the density near the origin is closely approximated by a Einasto profile.

Phenomenological aspects of theories for baryon and lepton number violation

International Nuclear Information System (INIS)

Duerr, Michael

2013-01-01

The renormalizable couplings of the Standard Model are invariant under two accidental global symmetries, which correspond to conserved baryon and lepton numbers. In this thesis, we discuss possible roles of these symmetries in extension of the Standard Model. Two approaches are considered: explicit violation of lepton number by two units in the renormalizable couplings of the Lagrangian, and promotion of the global symmetries to local gauge symmetries that are spontaneously broken. The former approach directly leads to Majorana neutrino masses and neutrinoless double beta decay. We discuss the interplay of the contributions to this decay in a one-loop neutrino mass model, the colored seesaw mechanism. We find that, depending on the parameters of the model, both the light Majorana neutrino exchange and the contribution of the new colored particles may be dominant. Additionally, an experimental test is presented, which allows for a discrimination of neutrinoless double beta decay from unknown nuclear background using only one isotope. In the latter approach, fascinating implications originate from the attempt to write down an anomaly-free and spontaneously broken gauge theory for baryon and lepton numbers, such as an automatically stable dark matter candidate. When gauging the symmetries in a left-right symmetric setup, the same fields that allow for an anomaly-free theory generate neutrino masses via the type III seesaw mechanism.

Mass and scattering length inequalities in QCD and QCD-like theories

International Nuclear Information System (INIS)

Nussinov, S.; Pennsylvania Univ., Philadelphia; Sathiapalan, B.

1985-01-01

Some observations about mass scattering length inequalities in QCD-like theories are presented. It is shown that the Weingarten mass inequality can be used to argue that global vector symmetries are unbroken in such theories. For QCD, in the limit Nsub(c)->infinite, it is shown that Msub(baryon)>=1/2Nsub(c)Msub(meson), provided there are at least Nsub(c) degenerate flavors of quarks. It is argued that when there are not bound states in a scattering channel, the mass inequalities can be used to derive inequalities beteen scattering lengths. Some rigorous inequalities for two and higher point functions for operators bilinear in currents are derived, and used to extract inequalities between quartic coupling constants. (orig.)

Helioseismology with long-range dark matter-baryon interactions

Energy Technology Data Exchange (ETDEWEB)

Lopes, Ilídio [Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Panci, Paolo [CP3-Origins and DIAS, University of Southern Denmark, DK-5230 Odense (Denmark); Silk, Joseph, E-mail: ilidio.lopes@tecnico.ulisboa.pt, E-mail: panci@iap.fr, E-mail: silk@astro.ox.ac.uk [Institut d' Astrophysique, UMR 7095 CNRS, Université Pierre et Marie Curie, 98bis Blvd Arago, F-75014 Paris (France)

2014-11-10

Assuming the existence of a primordial asymmetry in the dark sector, we study how long-range dark matter (DM)-baryon interactions, induced by the kinetic mixing of a new U(1) gauge boson and a photon, affect the evolution of the Sun and, in turn, the sound speed the profile obtained from helioseismology. Thanks to the explicit dependence on the exchanged momenta in the differential cross section (Rutherford-like scattering), we find that DM particles with a mass of ∼10 GeV, kinetic mixing parameter of the order of 10{sup –9}, and a mediator with a mass smaller than a few MeV improve the agreement between the best solar model and the helioseismic data without being excluded by direct detection experiments. In particular, the LUX detector will soon be able to either constrain or confirm our best-fit solar model in the presence of a dark sector with long-range interactions that reconcile helioseismology with thermal neutrino results.

Baryons with functional methods

International Nuclear Information System (INIS)

Fischer, Christian S.

2017-01-01

We summarise recent results on the spectrum of ground-state and excited baryons and their form factors in the framework of functional methods. As an improvement upon similar approaches we explicitly take into account the underlying momentum-dependent dynamics of the quark-gluon interaction that leads to dynamical chiral symmetry breaking. For light octet and decuplet baryons we find a spectrum in very good agreement with experiment, including the level ordering between the positive- and negative-parity nucleon states. Comparing the three-body framework with the quark-diquark approximation, we do not find significant differences in the spectrum for those states that have been calculated in both frameworks. This situation is different in the electromagnetic form factor of the Δ, which may serve to distinguish both pictures by comparison with experiment and lattice QCD.

Baryon form factors in chiral perturbation theory

Energy Technology Data Exchange (ETDEWEB)

Kubis, B.; Meissner, U.G. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik

2001-01-01

We analyze the electromagnetic form factors of the ground state baryon octet to fourth order in relativistic baryon chiral perturbation theory. Predictions for the {sigma}{sup -} charge radius and the {lambda}-{sigma}{sup 0} transition moment are found to be in excellent agreement with the available experimental information. Furthermore, the convergence behavior of the hyperon charge radii is shown to be more than satisfactory. (orig.)

The question of baryon conservation

International Nuclear Information System (INIS)

Goldhaber, M.

1983-01-01

A modern version of the law of baryon conservation might read: the net number of baryons (ΣB-ΣB-bar) does not change spontaneously or in any known interactions. For a long time it was believed that protons are absolutely stable, and neutrons sufficiently strongly bound by nuclei were also considered absolutely stable. Then a few years ago the grand unified theories were proposed in which strong, weak and electromagnetic interactions are combined, leading to the possibility that protons decay. Their lifetime is predictable in some of these theories. An experiment by the Irvine-Michigan-Brookhaven Collaboration to detect proton decays is described. (UK)

Understanding WIMP-baryon interactions with direct detection: a roadmap

International Nuclear Information System (INIS)

Gluscevic, Vera; Peter, Annika H.G.

2014-01-01

We study prospects of dark-matter direct-detection searches for probing non-relativistic effective theory for WIMP-baryon scattering. We simulate a large set of noisy recoil-energy spectra for different scattering scenarios (beyond the standard momentum-independent contact interaction), for Generation 2 and futuristic experiments. We analyze these simulations and quantify the probability of successfully identifying the operator governing the scattering, if a WIMP signal is observed. We find that the success rate depends on a combination of factors: the WIMP mass, the mediator mass, the type of interaction, and the experimental energy window. For example, for a 20 GeV WIMP, Generation 2 is only likely to identify the right operator if the interaction is Coulomb-like, and is unlikely to do so in any other case. For a WIMP with a mass of 200 GeV or higher, success is almost guaranteed. We also find that, regardless of the scattering model and the WIMP parameters, a single Generation 2 experiment is unlikely to successfully discern the momentum dependence of the underlying operator on its own, but prospects improve drastically when experiments with different target materials and energy windows are analyzed jointly. Furthermore, we examine the quality of parameter estimation and degeneracies in the multi-dimensional parameter space of the effective theory. We find in particular that the resulting WIMP mass estimates can be severely biased if data are analyzed assuming the standard (momentum-independent) operator while the actual operator has momentum-dependence. Finally, we evaluate the ultimate reach of direct detection, finding that the prospects for successful operator selection prior to reaching the irreducible backgrounds are excellent, if the signal is just below the current limits, but slim if Generation 2 does not report WIMP detection

Baryons and QCD

International Nuclear Information System (INIS)

Nathan Isgur

1997-01-01

The author presents an idiosyncratic view of baryons which calls for a marriage between quark-based and hadronic models of QCD. He advocates a treatment based on valence quark plus glue dominance of hadron structure, with the sea of q pairs (in the form of virtual hadron pairs) as important corrections

Beth-Uhlenbeck approach for repulsive interactions between baryons in a hadron gas

Science.gov (United States)

Vovchenko, Volodymyr; Motornenko, Anton; Gorenstein, Mark I.; Stoecker, Horst

2018-03-01

The quantum mechanical Beth-Uhlenbeck (BU) approach for repulsive hard-core interactions between baryons is applied to the thermodynamics of a hadron gas. The second virial coefficient a2—the "excluded volume" parameter—calculated within the BU approach is found to be temperature dependent, and it differs dramatically from the classical excluded volume (EV) model result. At temperatures T =100 -200 MeV, the widely used classical EV model underestimates the EV parameter for nucleons at a given value of the nucleon hard-core radius by large factors of 3-4. Previous studies, which employed the hard-core radii of hadrons as an input into the classical EV model, have to be re-evaluated using the appropriately rescaled EV parameters. The BU approach is used to model the repulsive baryonic interactions in the hadron resonance gas (HRG) model. Lattice data for the second- and fourth-order net baryon susceptibilities are described fairly well when the temperature dependent BU baryonic excluded volume parameter corresponds to nucleon hard-core radii of rc=0.25 -0.3 fm. Role of the attractive baryonic interactions is also considered. It is argued that HRG model with a constant baryon-baryon EV parameter vN N≃1 fm3 provides a simple yet efficient description of baryon-baryon interaction in the crossover temperature region.

Entropy per baryon in a 'many-worlds' cosmology

International Nuclear Information System (INIS)

Clutton-Brock, M.

1977-01-01

The universe is imagined split into infinitely many branches, or 'worlds', only one of which can be observed. The world has an entropy per baryon xi approximately 10 9 : other worlds can have all possible values of entropy per baryon. High-entropy worlds with xi > 5x10 11 do not form galaxies, but only giant black holes. Low entropy worlds with xi 5 do form galaxies, but only metal-poor dwarf galaxies with no planets. Life can evolve only in worlds with entropy per baryon in the range 3x10 5 11 , and life is abundant only in a much narrower range. (Auth.)

Modelling baryonic effects on galaxy cluster mass profiles

Science.gov (United States)

Shirasaki, Masato; Lau, Erwin T.; Nagai, Daisuke

2018-06-01

Gravitational lensing is a powerful probe of the mass distribution of galaxy clusters and cosmology. However, accurate measurements of the cluster mass profiles are limited by uncertainties in cluster astrophysics. In this work, we present a physically motivated model of baryonic effects on the cluster mass profiles, which self-consistently takes into account the impact of baryons on the concentration as well as mass accretion histories of galaxy clusters. We calibrate this model using the Omega500 hydrodynamical cosmological simulations of galaxy clusters with varying baryonic physics. Our model will enable us to simultaneously constrain cluster mass, concentration, and cosmological parameters using stacked weak lensing measurements from upcoming optical cluster surveys.

Modelling Baryonic Effects on Galaxy Cluster Mass Profiles

Science.gov (United States)

Shirasaki, Masato; Lau, Erwin T.; Nagai, Daisuke

2018-03-01

Gravitational lensing is a powerful probe of the mass distribution of galaxy clusters and cosmology. However, accurate measurements of the cluster mass profiles are limited by uncertainties in cluster astrophysics. In this work, we present a physically motivated model of baryonic effects on the cluster mass profiles, which self-consistently takes into account the impact of baryons on the concentration as well as mass accretion histories of galaxy clusters. We calibrate this model using the Omega500 hydrodynamical cosmological simulations of galaxy clusters with varying baryonic physics. Our model will enable us to simultaneously constrain cluster mass, concentration, and cosmological parameters using stacked weak lensing measurements from upcoming optical cluster surveys.

Measurement of inclusive B meson decays into baryons

International Nuclear Information System (INIS)

Albrecht, H.; Boeckmann, P.; Glaeser, R.; Harder, G.; Krueger, A.; Nippe, A.; Reidenbach, M.; Schaefer, M.; Schmidt-Parzefall, W.; Schroeder, H.; Schulz, H.D.; Sefkow, F.; Spengler, J.; Wurth, R.; Yagil, A.; Appuhn, R.D.; Drescher, A.; Hast, C.; Kamp, D.; Kolanoski, H.; Lindner, A.; Mankel, R.; Matthiesen, U.; Scheck, H.; Schweda, G.; Spaan, B.; Walther, A.; Wegener, D.; Frisken, W.R.; Kutschke, R.; Orr, R.S.; Parsons, J.A.; Prentice, J.D.; Seidel, S.C.; Swain, J.D.; Yoon, T.S.; MacFarlane, D.B.; McLean, K.W.; Nilsson, A.W.; Patel, P.M.; Tsipolitis, G.; Ammar, R.; Ball, S.; Coppage, D.; Davis, R.; Kanekal, S.; Kwak, N.; Ruf, T.; Schael, S.; Schubert, K.R.; Strahl, K.; Waldi, R.

1989-01-01

The decay of B mesons into the baryons p, Λ and Ξ - has been studied. The measured inclusive branching ratios for these decays are Br(B → pX) = (8.2±0.5 +1.3 -1.0 )%, Br(B → ΛX) = (4.2±0.5±0.6)% and Br(B → Ξ - X) < 0.51% at the 90% confidence level. In addition investigations on panti p, Λanti p and Λanti Λ correlations were performed, yielding an approximately equal rate of protons and neutrons. From this one can derive a total baryonic branching ratio Br(B → baryons) of (7.6±1.4)%. (orig.)

Chiral-symmetry restoration in baryon-rich environments

International Nuclear Information System (INIS)

Kogut, J.; Matsuoka, H.; Stone, M.; Wyld, H.W.; Shenker, S.; Shigemitsu, J.; Sinclair, D.K.

1983-04-01

Chiral symmetry restoration in an environment rich in baryons is studied by computer simulation methods in SU(2) and SU(3) gauge theories in the quenched approximation. The basic theory of symmetry restoration as a function of chemical potential is illustrated and the implementation of the ideas on a lattice is made explicit. A simple mean field model is presented to guide one's expectations. The second order conjugate-gradient iterative method and the pseudo-fermion Monte Carlo procedure are convergent methods of calculating the fermion propagator in an environment rich in baryons. Computer simulations of SU(3) gauge theory show an abrupt chiral symmetry restoring transition and the critical chemical potential and induced baryon density are estimated crudely. A smoother transition is observed for the color group SU(2)

Doubly-scattered-radiation contribution to Lidar returns from fog, evaluated by means of a simple geometrical approach

International Nuclear Information System (INIS)

Bruscaglioni, P.; Ismaelli, A.

1978-01-01

The contribution of doubly scattered radiation to the return of a monostatic Lidar, used for measurement of atmospheric visibility, is evaluated by means of a simple geometrical scheme. A very narrow laser beam is considered, to obtain an expression of the ratio D/S of doubly scattered power to singly scattered power. This assumption allows an easy consideration of any angle of scattering and the introduction of time into the calculations. Numerical computations are performed for several models of fog. Our results are similar, though a little lower, than the results of other theoretical treatments of this problem based on different assumptions. (author)

Magnetic moments of J{sup P} = (3)/(2){sup +} decuplet baryons using the statistical model

Energy Technology Data Exchange (ETDEWEB)

Kaur, Amanpreet; Upadhyay, Alka [Thapar University, School of Physics and Materials Science, Patiala (India)

2016-04-15

A suitable wave function for the baryon decuplet is framed with the inclusion of the sea containing quark-gluon Fock states. Relevant operator formalism is applied to calculate the magnetic moments of J{sup P} = (3)/(2){sup +} baryon decuplet. The statistical model assumes the decomposition of the baryonic state in various quark-gluon Fock states and is used in combination with the detailed balance principle to find the relative probabilities of these Fock states in flavor, spin and color space. The upper limit to the gluon is restricted to three with the possibility of emission of quark-antiquark pairs. We study the importance of strangeness in the sea (scalar, vector and tensor) and its contribution to the magnetic moments. Our approach has confirmed the scalar-tensor sea dominancy over the vector sea. Various modifications in the model are used to check the validity of the statistical approach. The results are matched with the available theoretical data. A good consistency with the experimental data has been achieved for Δ{sup ++}, Δ{sup +} and Ω{sup -}. (orig.)

Derivation of sum rules for quark and baryon fields

International Nuclear Information System (INIS)

Bongardt, K.

1978-01-01

In an analogous way to the Weinberg sum rules, two spectral-function sum rules for quark and baryon fields are derived by means of the concept of lightlike charges. The baryon sum rules are valid for the case of SU 3 as well as for SU 4 and the one-particle approximation yields a linear mass relation. This relation is not in disagreement with the normal linear GMO formula for the baryons. The calculated masses of the first resonance states agree very well with the experimental data

Simultaneous Generation of WIMP Miracle-like Densities of Baryons and Dark Matter

International Nuclear Information System (INIS)

McDonald, John

2012-01-01

The observed density of dark matter is of the magnitude expected for a thermal relic weakly-interacting massive particle (WIMP). In addition, the observed baryon density is within an order of magnitude of the dark matter density. This suggests that the baryon density is physically related to a typical thermal relic WIMP dark matter density. We present a model which simultaneously generates thermal relic WIMP-like densities for both baryons and dark matter by modifying a large initial baryon asymmetry. Production of unstable scalars carrying baryon number at the LHC would be a clear signature of the model.

Dispersion relation for hadronic light-by-light scattering: two-pion contributions

Energy Technology Data Exchange (ETDEWEB)

Colangelo, Gilberto [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, 3012 Bern (Switzerland); Hoferichter, Martin [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195-1550 (United States); Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA 93106 (United States); Procura, Massimiliano [Theoretical Physics Department, CERN, Geneva (Switzerland); Stoffer, Peter [Helmholtz-Institut für Strahlen- und Kernphysik (Theory)and Bethe Center for Theoretical Physics, University of Bonn, 53115 Bonn (Germany); Department of Physics, University of California at San Diego, La Jolla, CA 92093 (United States)

2017-04-27

In this third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in the HLbL contribution to the anomalous magnetic moment of the muon (g−2){sub μ}, including a detailed discussion of the unitarity relation for arbitrary partial waves. We show that obtaining a final expression free from unphysical helicity partial waves is a subtle issue, which we thoroughly clarify. As a by-product, we obtain a set of sum rules that could be used to constrain future calculations of γ{sup ∗}γ{sup ∗}→ππ. We validate the formalism extensively using the pion-box contribution, defined by two-pion intermediate states with a pion-pole left-hand cut, and demonstrate how the full known result is reproduced when resumming the partial waves. Using dispersive fits to high-statistics data for the pion vector form factor, we provide an evaluation of the full pion box, a{sub μ}{sup π-box}=−15.9(2)×10{sup −11}. As an application of the partial-wave formalism, we present a first calculation of ππ-rescattering effects in HLbL scattering, with γ{sup ∗}γ{sup ∗}→ππ helicity partial waves constructed dispersively using ππ phase shifts derived from the inverse-amplitude method. In this way, the isospin-0 part of our calculation can be interpreted as the contribution of the f{sub 0}(500) to HLbL scattering in (g−2){sub μ}. We argue that the contribution due to charged-pion rescattering implements corrections related to the corresponding pion polarizability and show that these are moderate. Our final result for the sum of pion-box contribution and its S-wave rescattering corrections reads a{sub μ}{sup π-box}+a{sub μ,J=0}{sup ππ,π-pole} {sup LHC}=−24(1)×10{sup −11}.

Streaming Velocities and the Baryon Acoustic Oscillation Scale.

Science.gov (United States)

Blazek, Jonathan A; McEwen, Joseph E; Hirata, Christopher M

2016-03-25

At the epoch of decoupling, cosmic baryons had supersonic velocities relative to the dark matter that were coherent on large scales. These velocities subsequently slow the growth of small-scale structure and, via feedback processes, can influence the formation of larger galaxies. We examine the effect of streaming velocities on the galaxy correlation function, including all leading-order contributions for the first time. We find that the impact on the baryon acoustic oscillation (BAO) peak is dramatically enhanced (by a factor of ∼5) over the results of previous investigations, with the primary new effect due to advection: if a galaxy retains memory of the primordial streaming velocity, it does so at its Lagrangian, rather than Eulerian, position. Since correlations in the streaming velocity change rapidly at the BAO scale, this advection term can cause a significant shift in the observed BAO position. If streaming velocities impact tracer density at the 1% level, compared to the linear bias, the recovered BAO scale is shifted by approximately 0.5%. This new effect, which is required to preserve Galilean invariance, greatly increases the importance of including streaming velocities in the analysis of upcoming BAO measurements and opens a new window to the astrophysics of galaxy formation.

Brightest group galaxies - II: the relative contribution of BGGs to the total baryon content of groups at z < 1.3

Science.gov (United States)

Gozaliasl, Ghassem; Finoguenov, Alexis; Khosroshahi, Habib G.; Henriques, Bruno M. B.; Tanaka, Masayuki; Ilbert, Olivier; Wuyts, Stijn; McCracken, Henry J.; Montanari, Francesco

2018-04-01

We performed a detailed study of the evolution of the star formation rate (SFR) and stellar mass of the brightest group galaxies (BGGs) and their relative contribution to the total baryon budget within R200 (f^{BGG}_{b,200}). The sample comprises 407 BGGs selected from X-ray groups (M200 = 1012.8-1014 M⊙) out to z ˜ 1.3 identified in the Cosmic Evolution Survey (COSMOS), XMM Large-Scale Structure survey (XMM-LSS), and the All-Wavelength Extended Groth strip International Survey (AEGIS) fields. We find that BGGs constitute two distinct populations of quiescent and star-forming galaxies and their mean SFR is ˜2 dex higher than the median SFR at z 2 dex. We take into account the halo mass growth of groups in selecting the sample of BGGs and find that the mean (median) stellar mass of BGGs has grown by 0.3 dex since z = 1.3 to the present day. We show that up to ˜ 45 per cent of the stellar mass growth in a star-forming BGG can be due to its star formation activity. With respect to f^{BGG}_{b,200}, we find it to increase with decreasing redshift by ˜0.35 dex, while decreasing with halo mass in a redshift-dependent manner. We show that the slope of the relation between f^{BGG}_{b,200} and halo mass increases negatively with decreasing redshift. This trend is driven by an insufficient star formation in BGGs, compared to the halo growth rate. We separately show the BGGs with the 20 per cent highest f^{BGG}_{b,200} are generally non-star-forming galaxies and grow in mass by processes not related to star formation (e.g. dry mergers and tidal striping). We present the M⋆-Mh and M⋆/Mh-Mh relations and compare them with semi-analytic model predictions and a number of results from the literature. We quantify the intrinsic scatter in stellar mass of BGGs at fixed halo mass (σ _{log M_{\\star}}) and find that σ _{{log }M_{\\star}} increases from 0.3 dex at z ˜ 0.2-0.5 dex at z ˜ 1.0 due to the bimodal distribution of stellar mass.

Dark matter-baryon segregation in the nonlinear evolution of coupled dark energy models

International Nuclear Information System (INIS)

Mainini, Roberto

2005-01-01

The growth and virialization of spherical top-hat fluctuations, in coupled dark energy models, causes segregation between dark matter (DM) and baryons, as the gravitational infall into the potential well proceeds more slowly for the baryons than for DM. As a consequence, after attaining their turnaround and before full virialization, halos have outer layers rich of baryons. Accordingly, a natural ambiguity exists on the definition of the virial density contrast. In fact, when the outer baryon layers infall onto the DM-richer core, they carry with them DM materials outside the original fluctuation; hence, no time exists when all materials originally belonging to the fluctuation--and only they--have virialized. Baryon-DM segregation can have various astrophysical consequences on different length scales. The smallest halos may loose up to 50% of the original baryonic contents and become hardly visible. Subhalos in cluster-size halos may loose much baryonic materials, which could then be observed as intracluster light. Isolated halos, in general, can be expected to have a baryon component richer than the cosmological proportions, due to the cosmic enrichement of baryons lost in small halo encounters

The Evolution of Galaxies by the Incompatibility between Dark Matter and Baryonic Matter

OpenAIRE

Chung, Ding-Yu

2001-01-01

In this paper, the evolution of galaxies is by the incompatibility between dark matter and baryonic matter. Due to the structural difference, baryonic matter and dark matter are incompatible to each other as oil droplet and water in emulsion. In the interfacial zone between dark matter and baryonic matter, this incompatibility generates the modification of Newtonian dynamics to keep dark matter and baryonic matter apart. The five periods of baryonic structure development in the order of incre...

P-odd two-pion potentials and asymmetry of pp scattering at low energies

International Nuclear Information System (INIS)

Musakhanov, M.M.; Podgornov, Y.Y.

1986-01-01

The asymmetry of pp scattering A/sub p//sub p/ is calculated using the potential approach for incident proton energies of 15 and 45 MeV taking into account the isovector P-odd two-pion interaction. The corresponding 2π potentials are obtained in the static approximation of the noncovariant technique taking into account Δ-isobar configurations. The pion-baryon cutoff form factors are taken from chiral bag models. Owing to the lack of reliable information on the nucleon bag radius R, the contribution of 2π exchange to A/sub p//sub p/ is given for the fairly wide range R = 0.4--1.0 F. The strong interaction is taken into account by the introduction of the phenomenological Reid soft-core and Paris potentials. It is shown that most of the 2π-exchange contribution comes from the region where the internucleon separations are larger than they are where the contribution of rho 0 - and ω-meson exchange dominates and that the former contribution must be included in A/sub p//sub p/. The resulting contribution of the 2π potential to A/sub p//sub p/ is of the same order as the contribution of the rho 0 and ω potentials

Weak form factors of beauty baryons

International Nuclear Information System (INIS)

Ivanov, M.A.; Lyubovitskij, V.E.

1992-01-01

Full analysis of semileptonic decays of beauty baryons with J p =1/2 2 and J p =3/2 2 into charmed ones within the Quark Confinement Model is reported. Weak form factors and decay rates are calculated. Also the heavy quark limit m Q →∞ (Isgur-Wise symmetry) is examined. The weak heavy-baryon form factors in the Isgur-Wise limit and 1/m Q -corrections to them are computered. The Ademollo-Gatto theorem is spin-flavour symmetry of heavy quarks is checked. 33 refs.; 1 fig.; 9 tabs

Heavy flavor baryons in hypercentral model

International Nuclear Information System (INIS)

Patel, Bhavin; Vinodkumar, P.C.; Rai, Ajay Kumar

2008-01-01

Heavy flavor baryons containing single and double charm (beauty) quarks with light flavor combinations are studied using the hypercentral description of the three- body problem. The confinement potential is assumed as hypercentral Coulomb plus power potential with power index υ. The ground state masses of the heavy flavor, J P = 1/2 + and 3/2 + baryons are computed for different power indices, υ starting from 0.5 to 2.0. The predicted masses are found to attain a saturated value in each case of quark combinations beyond the power index υ = 1.0. (author)

Non-baryonic dark matter

International Nuclear Information System (INIS)

Berkes, I.

1996-01-01

This article discusses the nature of the dark matter and the possibility of the detection of non-baryonic dark matter in an underground experiment. Among the useful detectors the low temperature bolometers are considered in some detail. (author)

Aharonov–Bohm protection of black hole's baryon/skyrmion hair

Energy Technology Data Exchange (ETDEWEB)

Dvali, Gia [Arnold-Sommerfeld-Center for Theoretical Physics, Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Gußmann, Alexander, E-mail: alexander.gussmann@physik.uni-muenchen.de [Arnold-Sommerfeld-Center for Theoretical Physics, Ludwig-Maximilians-Universität, 80333 München (Germany)

2017-05-10

The baryon/skyrmion correspondence implies that the baryon number is encoded into a topological surface integral. Under certain conditions that we clarify, this surface integral can be measured by an asymptotic observer in form of an Aharonov–Bohm phase-shift in an experiment in which the skyrmion passes through a loop of a probe string. In such a setup the baryon/skyrmion number must be respected by black holes, despite the fact that it produces no long-range classical field. If initially swallowed by a black hole, the baryon number must resurface in form of a classical skyrmion hair, after the black hole evaporates below a certain critical size. Needless to say, the respect of the baryon number by black holes is expected to have potentially-interesting astrophysical consequences.

Photoproduction of charmed baryons

International Nuclear Information System (INIS)

Russell, J.J.

1980-01-01

The results of a search for the photoproduction of charmed baryons in the broad-band neutral beam at Fermi National Accelerator Laboratory are reported. The lowest lying charmed baryon (Λ/sub c/ + ) is observed through its decay to p-anti K 0 . The cross section times branching ratio of γ + C → Λ/sub c/ + + X, γ + C → p + anti K 0 is measured to be sigma B = 3 nanobarns/nucleon. The total error on this measurement is estimated to be -20% to +40%. The mass of the Λ/sub c/ + is found to be 2.284 +- 0.001 GeV/c 2 , in good agreement with the Mark II result from SPEAR. Upper limits (90% confidence level) are set on sigma B for the modes Λ 0 π, Λ 0 πππ, pKπ

Simultaneous generation of WIMP miracle-like densities of baryons and dark matter

International Nuclear Information System (INIS)

McDonald, John

2011-01-01

The observed density of dark matter is of the magnitude expected for a thermal relic weakly-interacting massive particle (WIMP). In addition, the observed baryon density is within an order of magnitude of the dark matter density. This suggests that the baryon density is physically related to a typical thermal relic WIMP dark matter density. We present a model which simultaneously generates thermal relic WIMP-like densities for both baryons and dark matter by modifying a large initial baryon asymmetry. Dark matter is due to O(100) GeV gauge singlet scalars produced in the annihilation of the O(TeV) colored scalars which are responsible for the final thermal WIMP-like baryon asymmetry. The requirement of no baryon washout implies that there are two gauge singlet scalars. The low-temperature transfer of the asymmetry to conventional baryons can be understood if the long-lived O(TeV) colored scalars have large hypercharge, |Y|>4/3. Production of such scalars at the LHC would be a clear signature of the model.

Baryon considered as a soliton in loop space

International Nuclear Information System (INIS)

Kazakov, V.A.; Migdal, A.A.

1981-01-01

The baryon mass for large N is expressed in QCD in terms of the collective field in loop space, which satisfies the nonlinear functional-integral equation. This collective loop field is a relativistic generalization of the self-consistent Witten field. Our approach confirms Witten's idea that a baryon is a soliton in 1/N expansion

Massive pions, anomalies and baryons in holographic QCD

Energy Technology Data Exchange (ETDEWEB)

Domenech, O. [Departament de Fisica and IFAE, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Panico, G., E-mail: panico@phys.ethz.c [Institute for Theoretical Physics, ETH Zurich, 8093 Zurich (Switzerland); Wulzer, A. [Institut de Theorie des Phenomenes Physiques, EPFL, CH-1015 Lausanne (Switzerland)

2011-03-01

We consider a holographic model of QCD, obtained by a very simple modification of the original construction, which describes at the same time the pion mass, the QCD anomalies and the baryons as topological solitons. We study in detail its phenomenological implications in both the mesonic and baryonic sectors and compare with the observations.

Measurement of baryon production in B-meson decay

International Nuclear Information System (INIS)

Crawford, G.; Fulton, R.; Jensen, T.; Johnson, D.R.; Kagan, H.; Kass, R.; Malchow, R.; Morrow, F.; Whitmore, J.; Wilson, P.; Bortoletto, D.; Brown, D.; Dominick, J.; McIlwain, R.L.; Miller, D.H.; Modesitt, M.; Ng, C.R.; Schaffner, S.F.; Shibata, E.I.; Shipsey, I.P.J.; Battle, M.; Kroha, H.; Sparks, K.; Thorndike, E.H.; Wang, C.; Alam, M.S.; Kim, I.J.; Li, W.C.; Lou, X.C.; Nemati, B.; Romero, V.; Sun, C.R.; Wang, P.; Zoeller, M.M.; Goldberg, M.; Haupt, T.; Horwitz, N.; Jain, V.; Kennett, R.; Mestayer, M.D.; Moneti, G.C.; Rozen, Y.; Rubin, P.; Skwarnicki, T.; Stone, S.; Thusalidas, M.; Yao, W.; Zhu, G.; Barnes, A.V.; Bartelt, J.; Csorna, S.E.; Letson, T.; Alexander, J.; Artuso, M.; Bebek, C.; Berkelman, K.; Besson, D.; Browder, T.; Cassel, D.G.; Cheu, E.; Coffman, D.M.; Drell, P.S.; Ehrlich, R.; Galik, R.S.; Garcia-Sciveres, M.; Geiser, B.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Honscheid, K.; Kandaswamy, J.; Katayama, N.; Kreinick, D.L.; Lewis, J.D.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Nandi, S.; Nordberg, E.; O'Grady, C.; Patterson, J.R.; Peterson, D.; Pisharody, M.; Riley, D.; Sapper, M.; Selen, M.; Silverman, A.; Worden, H.; Worris, M.; Sadoff, A.J.; Avery, P.; Freyberger, A.; Rodriguez, J.; Yelton, J.; Henderson, S.; Kinoshita, K.; Pipkin, F.; Procario, M.; Saulnier, M.; Wilson, R.; Wolinski, J.; Xiao, D.; Yamamoto, H.; Ammar, R.; Baringer, P.; Coppage, D.; Davis, R.; Haas, P.; Kelly, M.; Kwak, N.; Lam, H.; Ro, S.; Kubota, Y.; Nelson, J.K.; Perticone, D.; Poling, R.; Schrenk, S.

1992-01-01

Using the CLEO detector at the Cornell Electron Storage Ring, we observe B-meson decays to Λ c + and report on improved measurements of inclusive branching fractions and momentum spectra of other baryons. For the inclusive decay bar B→Λ c + X with Λ c + →pK - π + , we find that the product branching fraction B(bar B→Λ c + X)B(Λ c + →pK - π + )=(0.273±0.051± 0.039)%. Our measured inclusive branching fractions to noncharmed baryons are B(B→pX)=(8.0±0.5±0.3)%, B(B→ΛX)=(3.8±0.4±0.6)%, and B(B→Ξ - X)=(0.27±0.05±0.04)%. From these rates and studies of baryon-lepton and baryon-antibaryon correlations in B decays, we have estimated the branching fraction B(bar B→Λ c + X) to be (6.4±0.8±0.8)%. Combining these results, we calculate B(Λ c + →pK - π + ) to be (4.3±1.0±0.8)%

Entropy per baryon in a 'many-worlds' cosmology

Energy Technology Data Exchange (ETDEWEB)

Clutton-Brock, M [Manitoba Univ., Winnipeg (Canada)

1977-04-01

The universe is imagined split into infinitely many branches, or 'worlds', only one of which can be observed. The world has an entropy per baryon xi approximately 10/sup 9/: other worlds can have all possible values of entropy per baryon. High-entropy worlds with xi > 5x10/sup 11/ do not form galaxies, but only giant black holes. Low entropy worlds with xi < 3x10/sup 5/ do form galaxies, but only metal-poor dwarf galaxies with no planets. Life can evolve only in worlds with entropy per baryon in the range 3x10/sup 5/ < xi < 5x10/sup 11/, and life is abundant only in a much narrower range.

Baryon Content in a Sample of 91 Galaxy Clusters Selected by the South Pole Telescope at 0.2 < z < 1.25

Science.gov (United States)

Chiu, I.; Mohr, J. J.; McDonald, M.; Bocquet, S.; Desai, S.; Klein, M.; Israel, H.; Ashby, M. L. N.; Stanford, A.; Benson, B. A.; Brodwin, M.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Bayliss, M.; Benoit-Lévy, A.; Bertin, E.; Bleem, L.; Brooks, D.; Buckley-Geer, E.; Bulbul, E.; Capasso, R.; Carlstrom, J. E.; Rosell, A. Carnero; Carretero, J.; Castander, F. J.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Davis, C.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Drlica-Wagner, A.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; García-Bellido, J.; Garmire, G.; Gaztanaga, E.; Gerdes, D. W.; Gonzalez, A.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gupta, N.; Gutierrez, G.; Hlavacek-L, J.; Honscheid, K.; James, D. J.; Jeltema, T.; Kraft, R.; Krause, E.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; Lahav, O.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Menanteau, F.; Miquel, R.; Murray, S.; Nord, B.; Ogando, R. L. C.; Plazas, A. A.; Rapetti, D.; Reichardt, C. L.; Romer, A. K.; Roodman, A.; Sanchez, E.; Saro, A.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sharon, K.; Smith, R. C.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Stalder, B.; Stern, C.; Strazzullo, V.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Vikram, V.; Walker, A. R.; Weller, J.; Zhang, Y.

2018-05-01

We estimate total mass (M500), intracluster medium (ICM) mass (MICM) and stellar mass (M⋆) in a Sunyaev-Zel'dovich effect (SZE) selected sample of 91 galaxy clusters with masses M500 ≳ 2.5 × 1014M⊙ and redshift 0.2 baryonic mass and the cold baryonic fraction with cluster halo mass and redshift. We find significant departures from self-similarity in the mass scaling for all quantities, while the redshift trends are all statistically consistent with zero, indicating that the baryon content of clusters at fixed mass has changed remarkably little over the past ≈9 Gyr. We compare our results to the mean baryon fraction (and the stellar mass fraction) in the field, finding that these values lie above (below) those in cluster virial regions in all but the most massive clusters at low redshift. Using a simple model of the matter assembly of clusters from infalling groups with lower masses and from infalling material from the low density environment or field surrounding the parent halos, we show that the measured mass trends without strong redshift trends in the stellar mass scaling relation could be explained by a mass and redshift dependent fractional contribution from field material. Similar analyses of the ICM and baryon mass scaling relations provide evidence for the so-called "missing baryons" outside cluster virial regions.

The effective baryon-lepton coupling constant and the parity of leptons

International Nuclear Information System (INIS)

Lucha, W.; Stremnitzer, H.

1981-01-01

Using a phenomenological ansatz for the Lagrangian of baryon- and lepton-number violating interactions the effective baryon-lepton coupling constant is calculated within the framework of a relativistic quark model. Apart from a calculation of B-number violating cross-sections and decays this ansatz allows for a definition of the parity of leptons relative to baryons. (Auth.)

Excited state mass spectra of doubly heavy Ξ baryons

Energy Technology Data Exchange (ETDEWEB)

Shah, Zalak; Rai, Ajay Kumar [Sardar Vallabhbhai National Institute of Technology, Department of Applied Physics, Surat, Gujarat (India)

2017-02-15

In this paper, the mass spectra are obtained for doubly heavy Ξ baryons, namely, Ξ{sub cc}{sup +}, Ξ{sub cc}{sup ++}, Ξ{sub bb}{sup -}, Ξ{sub bb}{sup 0}, Ξ{sub bc}{sup 0} and Ξ{sub bc}{sup +}. These baryons consist of two heavy quarks (cc, bb, and bc) with a light (d or u) quark. The ground, radial, and orbital states are calculated in the framework of the hypercentral constituent quark model with Coulomb plus linear potential. Our results are also compared with other predictions, thus, the average possible range of excited states masses of these Ξ baryons can be determined. The study of the Regge trajectories is performed in (n, M{sup 2}) and (J, M{sup 2}) planes and their slopes and intercepts are also determined. Lastly, the ground state magnetic moments of these doubly heavy baryons are also calculated. (orig.)

Search for Baryon-Number Violating Ξ_{b}^{0} Oscillations.

Science.gov (United States)

Aaij, R; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Alfonso Albero, A; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Archilli, F; d'Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Babuschkin, I; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baker, S; Balagura, V; Baldini, W; Baranov, A; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Baryshnikov, F; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Beiter, A; Bel, L J; Beliy, N; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Beranek, S; Berezhnoy, A; Bernet, R; Berninghoff, D; Bertholet, E; Bertolin, A; Betancourt, C; Betti, F; Bettler, M-O; van Beuzekom, M; Bezshyiko, Ia; Bifani, S; Billoir, P; Birnkraut, A; Bitadze, A; Bizzeti, A; Bjørn, M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N; Bonivento, W; Bordyuzhin, I; Borgheresi, A; Borghi, S; Borisyak, M; Borsato, M; Bossu, F; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britton, T; Brodzicka, J; Brundu, D; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Byczynski, W; Cadeddu, S; Cai, H; Calabrese, R; Calladine, R; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D H; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cavallero, G; Cenci, R; Chamont, D; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S F; Chitic, S-G; Chobanova, V; Chrzaszcz, M; Chubykin, A; Ciambrone, P; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collins, P; Colombo, T; Comerma-Montells, A; Contu, A; Cook, A; Coombs, G; Coquereau, S; Corti, G; Corvo, M; Costa Sobral, C M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Currie, R; D'Ambrosio, C; Da Cunha Marinho, F; Dall'Occo, E; Dalseno, J; Davis, A; De Aguiar Francisco, O; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Serio, M; De Simone, P; Dean, C T; Decamp, D; Del Buono, L; Dembinski, H-P; Demmer, M; Dendek, A; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Di Nezza, P; Dijkstra, H; Dordei, F; Dorigo, M; Dosil Suárez, A; Douglas, L; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Durante, P; Dzhelyadin, R; Dziewiecki, M; Dziurda, A; Dzyuba, A; Easo, S; Ebert, M; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Farley, N; Farry, S; Fazzini, D; Federici, L; Ferguson, D; Fernandez, G; Fernandez Declara, P; Fernandez Prieto, A; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fini, R A; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fleuret, F; Fohl, K; Fontana, M; Fontanelli, F; Forshaw, D C; Forty, R; Franco Lima, V; Frank, M; Frei, C; Fu, J; Funk, W; Furfaro, E; Färber, C; Gabriel, E; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; Garcia Martin, L M; García Pardiñas, J; Garra Tico, J; Garrido, L; Garsed, P J; Gascon, D; Gaspar, C; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gizdov, K; Gligorov, V V; Golubkov, D; Golutvin, A; Gomes, A; Gorelov, I V; Gotti, C; Govorkova, E; Grabowski, J P; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Greim, R; Griffith, P; Grillo, L; Gruber, L; Gruberg Cazon, B R; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Göbel, C; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hamilton, B; Han, X; Hancock, T H; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hasse, C; Hatch, M; He, J; Hecker, M; Heinicke, K; Heister, A; Hennessy, K; Henrard, P; Henry, L; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hombach, C; Hopchev, P H; Huard, Z C; Hulsbergen, W; Humair, T; Hushchyn, M; Hutchcroft, D; Ibis, P; Idzik, M; Ilten, P; Jacobsson, R; Jalocha, J; Jans, E; Jawahery, A; Jiang, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Karacson, M; Kariuki, J M; Karodia, S; Kazeev, N; Kecke, M; Kelsey, M; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Klimkovich, T; Koliiev, S; Kolpin, M; Komarov, I; Kopecna, R; Koppenburg, P; Kosmyntseva, A; Kotriakhova, S; Kozeiha, M; Kravchuk, L; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; Leflat, A; Lefrançois, J; Lefèvre, R; Lemaitre, F; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, P-R; Li, T; Li, Y; Li, Z; Likhomanenko, T; Lindner, R; Lionetto, F; Lisovskyi, V; Liu, X; Loh, D; Loi, A; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Macko, V; Mackowiak, P; Maddrell-Mander, S; Maev, O; Maguire, K; Maisuzenko, D; Majewski, M W; Malde, S; Malinin, A; Maltsev, T; Manca, G; Mancinelli, G; Manning, P; Marangotto, D; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marinangeli, M; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurice, E; Maurin, B; Mazurov, A; McCann, M; McNab, A; McNulty, R; Mead, J V; Meadows, B; Meaux, C; Meier, F; Meinert, N; Melnychuk, D; Merk, M; Merli, A; Michielin, E; Milanes, D A; Millard, E; Minard, M-N; Minzoni, L; Mitzel, D S; Mogini, A; Molina Rodriguez, J; Mombacher, T; Monroy, I A; Monteil, S; Morandin, M; Morello, M J; Morgunova, O; Moron, J; Morris, A B; Mountain, R; Muheim, F; Mulder, M; Müller, D; Müller, J; Müller, K; Müller, V; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, T D; Nguyen-Mau, C; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Nogay, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Oldeman, R; Onderwater, C J G; Ossowska, A; Otalora Goicochea, J M; Owen, P; Oyanguren, A; Pais, P R; Palano, A; Palutan, M; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parker, W; Parkes, C; Passaleva, G; Pastore, A; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petrov, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Placinta, V; Playfer, S; Plo Casasus, M; Polci, F; Poli Lener, M; Poluektov, A; Polyakov, I; Polycarpo, E; Pomery, G J; Ponce, S; Popov, A; Popov, D; Poslavskii, S; Potterat, C; Price, E; Prisciandaro, J; Prouve, C; Pugatch, V; Puig Navarro, A; Pullen, H; Punzi, G; Qian, W; Quagliani, R; Quintana, B; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Ratnikov, F; Raven, G; Ravonel Salzgeber, M; Reboud, M; Redi, F; Reichert, S; Dos Reis, A C; Remon Alepuz, C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Robert, A; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Rollings, A; Romanovskiy, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Rudolph, M S; Ruf, T; Ruiz Valls, P; Ruiz Vidal, J; Saborido Silva, J J; Sadykhov, E; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarpis, G; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schellenberg, M; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schreiner, H F; Schubert, K; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sepulveda, E S; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Simone, S; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Soares Lavra, L; Sokoloff, M D; Soler, F J P; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefko, P; Stefkova, S; Steinkamp, O; Stemmle, S; Stenyakin, O; Stepanova, M; Stevens, H; Stone, S; Storaci, B; Stracka, S; Stramaglia, M E; Straticiuc, M; Straumann, U; Sun, J; Sun, L; Sutcliffe, W; Swientek, K; Syropoulos, V; Szczekowski, M; Szumlak, T; Szymanski, M; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, E; van Tilburg, J; Tilley, M J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Toriello, F; Tourinho Jadallah Aoude, R; Tournefier, E; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tully, A; Tuning, N; Ukleja, A; Usachov, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagner, A; Vagnoni, V; Valassi, A; Valat, S; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Venkateswaran, A; Verlage, T A; Vernet, M; Vesterinen, M; Viana Barbosa, J V; Viaud, B; Vieira, D; Vieites Diaz, M; Viemann, H; Vilasis-Cardona, X; Vitti, M; Volkov, V; Vollhardt, A; Voneki, B; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Vázquez Sierra, C; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Wark, H M; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Winn, M; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wyllie, K; Xie, Y; Xu, Z; Yang, Z; Yang, Z; Yao, Y; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zarebski, K A; Zavertyaev, M; Zhang, L; Zhang, Y; Zhelezov, A; Zheng, Y; Zhu, X; Zhukov, V; Zonneveld, J B; Zucchelli, S

2017-11-03

A search for baryon-number violating Ξ_{b}^{0} oscillations is performed with a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 3  fb^{-1}. The baryon number at the moment of production is identified by requiring that the Ξ_{b}^{0} come from the decay of a resonance Ξ_{b}^{*-}→Ξ_{b}^{0}π^{-} or Ξ_{b}^{'-}→Ξ_{b}^{0}π^{-}, and the baryon number at the moment of decay is identified from the final state using the decays Ξ_{b}^{0}→Ξ_{c}^{+}π^{-},Ξ_{c}^{+}→pK^{-}π^{+}. No evidence of baryon-number violation is found, and an upper limit at the 95% confidence level is set on the oscillation rate of ω<0.08  ps^{-1}, where ω is the associated angular frequency.

Spontaneous violation of chiral symmetry in QCD vacuum is the origin of baryon masses and determines baryon magnetic moments and their other static properties

International Nuclear Information System (INIS)

Ioffe, B. L.

2009-01-01

A short review is presented of the spontaneous violation of chiral symmetry in QCD vacuum. It is demonstrated that this phenomenon is the origin of baryon masses in QCD. The value of nucleon mass is calculated, as well as the masses of hyperons and some baryonic resonances, and expressed mainly through the values of quark condensates - , q = u, d, s,-the vacuum expectation values (v.e.v.) of quark field. The concept of v.e.v. induced by external fields is introduced. It is demonstrated that such v.e.v. induced by static electromagnetic field results in quark condensate magnetic susceptibility, which plays the main role in determination of baryon magnetic moments. The magnetic moments of proton, neutron, and hyperons are calculated. The results of calculation of baryon octet β-decay constants are also presented.

Investigation of the leading and subleading high-energy behavior of hadron-hadron total cross sections using a best-fit analysis of hadronic scattering data

Science.gov (United States)

Giordano, M.; Meggiolaro, E.; Silva, P. V. R. G.

2017-08-01

In the present investigation we study the leading and subleading high-energy behavior of hadron-hadron total cross sections using a best-fit analysis of hadronic scattering data. The parametrization used for the hadron-hadron total cross sections at high energy is inspired by recent results obtained by Giordano and Meggiolaro [J. High Energy Phys. 03 (2014) 002, 10.1007/JHEP03(2014)002] using a nonperturbative approach in the framework of QCD, and it reads σtot˜B ln2s +C ln s ln ln s . We critically investigate if B and C can be obtained by means of best-fits to data for proton-proton and antiproton-proton scattering, including recent data obtained at the LHC, and also to data for other meson-baryon and baryon-baryon scattering processes. In particular, following the above-mentioned nonperturbative QCD approach, we also consider fits where the parameters B and C are set to B =κ Bth and C =κ Cth, where Bth and Cth are universal quantities related to the QCD stable spectrum, while κ (treated as an extra free parameter) is related to the asymptotic value of the ratio σel/σtot. Different possible scenarios are then considered and compared.

Polarized heavy baryon production in quark-diquark model considering two different scenarios

Energy Technology Data Exchange (ETDEWEB)

Moosavi Nejad, S.M. [Yazd University, Faculty of Physics, Yazd (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, Tehran (Iran, Islamic Republic of); Delpasand, M. [Yazd University, Faculty of Physics, Yazd (Iran, Islamic Republic of)

2017-09-15

At sufficiently large transverse momentum, the dominant production mechanism for heavy baryons is actually the fragmentation. In this work, we first study the direct fragmentation of a heavy quark into the unpolarized triply heavy baryons in the leading order of perturbative QCD. In a completely different approach, we also analyze the two-stage fragmentation of a heavy quark into a scalar diquark followed by the fragmentation of such a scalar diquark into a triply heavy baryon: quark-diquark model of baryons. The results of this model are in acceptable agreement with those obtained through a full perturbative regime. Relying on the quark-diquark model and considering two different scenarios we determine the spin-dependent fragmentation functions of polarized heavy baryons in such a way that a vector or a pseudoscalar heavy diquark is an intermediate particle between the initial heavy quark and the final state baryon. (orig.)

Entropy and baryon number conservation in the deconfinement phase transition

International Nuclear Information System (INIS)

Leonidov, A.; Redlich, K.; Satz, H.; Suhonen, E.; Weber, G.

1994-01-01

The conservation of entropy and baryon number in the deconfinement phase transition is studied in the framework of the bag model. In the standard construction of the equilibrium phase transition from a quark-gluon plasma into a hadron gas a subsequent dilution and reheating of the system on the phase boundary is necessary to preserve the entropy and baryon number conservation. We propose modifying the bag pressure to depend explicitly on temperature and baryon chemical potential. It is shown that this modification is sufficient to construct a model in agreement with the Gibbs equilibrium criteria for a phase transition, while simultaneously assuring entropy and baryon number conservation on the phase boundary. Within this model the quark-gluon plasma hadronizes at a fixed temperature and chemical potential

1/M corrections to baryonic form factors in the quark model

International Nuclear Information System (INIS)

Cheng, H.; Tseng, B.

1996-01-01

Weak current-induced baryonic form factors at zero recoil are evaluated in the rest frame of the heavy parent baryon using the nonrelativistic quark model. Contrary to previous similar work in the literature, our quark model results do satisfy the constraints imposed by heavy quark symmetry for heavy-heavy baryon transitions at the symmetric point v·v'=1 and are in agreement with the predictions of the heavy quark effective theory for antitriplet-antitriplet heavy baryon form factors at zero recoil evaluated to order 1/m Q . Furthermore, the quark model approach has the merit that it is applicable to any heavy-heavy and heavy-light baryonic transitions at maximum q 2 . Assuming a dipole q 2 behavior, we have applied the quark model form factors to nonleptonic, semileptonic, and weak radiative decays of the heavy baryons. It is emphasized that the flavor suppression factor occurring in many heavy-light baryonic transitions, which is unfortunately overlooked in most literature, is very crucial towards an agreement between theory and experiment for the semileptonic decay Λ c →Λe + ν e . Predictions for the decay modes Λ b →J/ψΛ, Λ c →pφ, Λ b →Λγ, Ξ b →Ξγ, and for the semileptonic decays of Λ b , Ξ b, c, and Ω b are presented. copyright 1996 The American Physical Society

Baryon inhomogeneity from the cosmic quark-hadron phase transition

International Nuclear Information System (INIS)

Kurki-Suonio, H.

1991-01-01

We discuss the generation of inhomogeneity in the baryon-number density during the cosmic quark-hadron phase transition. We use a simple model with thin-wall phase boundaries and ideal-gas equations of state. The nucleation of the phase transition introduces a new distance scale into the universe which will be the scale of the generated inhomogeneity. We review the estimate of this scale. During the transition baryon number is likely to collect onto a layer at the phase boundary. These layers may in the end be deposited as small regions of very high baryon density. 21 refs., 1 fig

Observational constraints on dark matter-dark energy scattering cross section

Energy Technology Data Exchange (ETDEWEB)

Kumar, Suresh [BITS Pilani, Department of Mathematics, Rajasthan (India); Nunes, Rafael C. [Universidade Federal de Juiz de Fora, Departamento de Fisica, Juiz de Fora, MG (Brazil)

2017-11-15

In this letter, we report precise and robust observational constraints on the dark matter-dark energy scattering cross section, using the latest data from cosmic microwave background (CMB) Planck temperature and polarization, baryon acoustic oscillations (BAO) measurements and weak gravitational lensing data from Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). The scattering scenario consists of a pure momentum exchange between the dark components, and we find σ{sub d} < 10{sup -29} cm{sup 2} (m{sub dm}c{sup 2}/GeV) at 95% CL from the joint analysis (CMB + BAO + CFHTLenS), where m{sub dm} is a typical dark matter particle mass. We notice that the scattering among the dark components may influence the growth of large scale structure in the Universe, leaving the background cosmology unaltered. (orig.)

Baryon resonances in nuclei

International Nuclear Information System (INIS)

Arenhoevel, H.

1977-01-01

The field of baryon resonances in nuclei is reviewed. Theoretical developments and experimental evidence as well are discussed. Special emphasis is laid on electromagnetic processes for the two nucleon system. Some aspects of real isobars in nuclei are touched upon. (orig.) [de

White noise from dark matter: 21 cm observations of early baryon collapse

International Nuclear Information System (INIS)

Zurek, Kathryn M.; Hogan, Craig J.

2007-01-01

In concordance cosmology, dark matter density perturbations generated by inflation lead to nonlinear, virialized minihalos, into which baryons collapse at redshift z∼20. We survey here novel baryon evolution produced by a modification of the power spectrum from white noise density perturbations at scales below k∼10h Mpc -1 (the smallest scales currently measured with the Lyman-α forest). Exotic dark matter dynamics, such as would arise from scalar dark matter with a late phase transition (similar to an axion, but with lower mass), or primordial black hole dark matter, create such an amplification of small scale power. The dark matter produced in such a phase transition collapses into minihalos, with a size given by the dark matter mass within the horizon at the phase transition. If the mass of the initial minihalos is larger than ∼10 -3 M · , the modified power spectrum is found to cause widespread baryon collapse earlier than standard ΛCDM, leading to earlier gas heating. It also results in higher spin temperature of the baryons in the 21 cm line relative to ΛCDM at redshifts z>20 if the mass of the minihalo is larger than 1M · . It is estimated that experiments probing 21 cm radiation at high redshift will contribute a significant constraint on dark matter models of this type for initial minihalos larger than ∼10M · . These experiments may also detect (or rule out) primordial black holes as the dark matter in the window 30M · H 3 M · still left open by strong microlensing experiments and other astrophysical constraints. Early experiments reaching to z≅15 will constrain minihalos down to ∼10 3 M ·

COUPLED-CHANNELS FADDEEV CALCULATION OF THE K(-) d SCATTERING LENGTH

Czech Academy of Sciences Publication Activity Database

Shevchenko, Nina V.

2011-01-01

Roč. 26, 3-4 (2011), s. 558-560 ISSN 0217-751X. [11th International Workshop on Meson Production , Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA AV ČR KJB100480801 Institutional research plan: CEZ:AV0Z10480505 Keywords : Few-body systems * multichannel scattering * antikaon-baryon interaction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.053, year: 2011

Dark matter assimilation into the baryon asymmetry

International Nuclear Information System (INIS)

D'Eramo, Francesco; Fei, Lin; Thaler, Jesse

2012-01-01

Pure singlets are typically disfavored as dark matter candidates, since they generically have a thermal relic abundance larger than the observed value. In this paper, we propose a new dark matter mechanism called a ssimilation , which takes advantage of the baryon asymmetry of the universe to generate the correct relic abundance of singlet dark matter. Through assimilation, dark matter itself is efficiently destroyed, but dark matter number is stored in new quasi-stable heavy states which carry the baryon asymmetry. The subsequent annihilation and late-time decay of these heavy states yields (symmetric) dark matter as well as (asymmetric) standard model baryons. We study in detail the case of pure bino dark matter by augmenting the minimal supersymmetric standard model with vector-like chiral multiplets. In the parameter range where this mechanism is effective, the LHC can discover long-lived charged particles which were responsible for assimilating dark matter

Heavy baryon transitions and the heavy quark effective theory

International Nuclear Information System (INIS)

Hussain, F.

1992-01-01

Heavy baryon decays are studied in the context of the Bethe-Salpeter approach to the heavy quark effective theory. A drastic reduction, in the number of independent form factors, is found. Results are presented both for heavy to heavy and heavy to light baryon decays. (orig.)

Search for strange baryon electric dipole moment at LHCb

CERN Document Server

Lewis, Daniel James

2017-01-01

A search for the EDM of $\\Lambda$ baryons using the LHCb detector is proposed. In order to perform this search, the reconstruction of $\\Lambda$ baryons using T tracks must be possible. This note presents the reconstruction techniques and resolution studies that demonstrate that this is indeed feasible.

Recent soft-core baryon-baryon interactions

International Nuclear Information System (INIS)

Rijken, Th.A.; Yamamoto, Y.

2005-01-01

We present recent results obtained with the extended soft-core (ESC) interactions. This ESC-model, henceforth called ESC03, describes nucleon-nucleon (NN), hyperon-nucleon (YN), and hyperon-hyperon (YY), in a unified manner using (broken) SUf(3)-symmetry. Novel ingredients are the inclusion of (i) the axial-vector meson potentials (ii) a zero in the scalar-meson form-factors. With these innovations, it proved possible for the first time to keep the parameters of the model closely to the predictions of the P03 quark-pair-creation model (QPC). This is the case for the meson-baryon coupling constants and F/(F+D)-ratio's as well. Also, the YN and YY results for this model are rather excellent

The contribution of neutron scattering to molecular biology

International Nuclear Information System (INIS)

Stuhrmann, H.B.

1983-01-01

About half of the atoms of living cells are hydrogens, and nearly all biological applications of neutron scattering rely on the well-known difference in the scattering lengths of the proton and the deuteron. This introduces us to a wide variety of biological problems, which are related with hydrogen in water, proteins, nucleic acids and lipids. Neutron scattering gives an answer to both structural and dynamical aspects of the system in question. With deuterium labelled samples unambiguous information about molecular structure and motion becomes accessible. The architecture of viruses, cell membranes and gene expressing molecules has become a lot clearer with neutron scattering. (author)

Electromagnetic properties of baryons in the constituent quark model

International Nuclear Information System (INIS)

Warns, M.

1992-01-01

The electromagnetic properties of baryons are investigated in the framework of a relativized quark model. The model includes beyond the usual single quark transition ansatz relativistic effects due to the strong interaction and confinement forces between the quarks. Furthermore the center-of-mass motion of the three-quark system is separated off in a Lorentz-invariant way. All relativistic correction terms are obtained by expanding the corresponding relativistic expressions in powers of the quark velocity. In this way recoil effects on the electromagnetic interaction between the photon and the baryon could be explicitly studied. Using the harmonic oscillator wavefunctions with the configuration mixing from the Isgur-Karl model, the form factors of the nucleon and the electromagnetic transition amplitudes both for longitudinally and transversely polarized photons are calculated for the most important baryon resonances. An extension to baryons involving strange quarks is also considered. Comparisons are made with the results of the nonrelativistic quark model and with some other approaches. (orig.)

Factorization of heavy-to-light baryonic transitions in SCET

International Nuclear Information System (INIS)

Wang Wei

2012-01-01

In the framework of the soft-collinear effective theory, we demonstrate that the leading-power heavy-to-light baryonic form factors at large recoil obey the heavy quark and large energy symmetries. Symmetry breaking effects are suppressed by Λ/m b or Λ/E, where Λ is the hadronic scale, m b is the b quark mass and E∼m b is the energy of light baryon in the final state. At leading order, the leading power baryonic form factor ξ Λ,p (E), in which two hard-collinear gluons are exchanged in the baryon constituents, can factorize into the soft and collinear matrix elements convoluted with a hard-kernel of order α s 2 . Including the energy release dependence, we derive the scaling law ξ Λ,p (E)∼Λ 2 /E 2 . We also find that this form factor ξ Λ (E) is numerically smaller than the form factor governed by soft processes, although the latter is formally power-suppressed.

Baryon Regge trajectories from the area-law of Wilson loop

International Nuclear Information System (INIS)

Simonov, Yu.A.

1989-01-01

In the proper-time path integral representation of the three-quark Green function, baryon masses are calculated for large angular momenta L. Dynamics is given by vacuum background fields in the Wilson loop. Assuming an area law for large Wilson loops one obtains linear baryon Regge trajectories with the same slope as for mesons. For large L the baryon has an asymmetric structure of the quark-diquark type. Dynamic masses of the quark and diquark are generated, which grow with L. 8 refs

Note on the two inequivalent spin 1/2 baryon field operators

International Nuclear Information System (INIS)

Christos, G.A.

1985-01-01

There are two inequivalent spin 1/2 local baryon field operators that can be constructed from 3 quarks. A priori the Jsup(P)=1/2 + baryons can couple to any linear combination of these operators. We show however that the coupling of the 1/2 + baryons to these operators is determined by the value of the SU(3) ratio of F to D type peudoscalar-baryon couplings. The experimental value of this ratio implies, for example, that the proton couples strongly to (usup(T)Cγ 5 d)u and weakly to (usup(T)Cd)γ 5 u. This is of interest in QCD sum rule applications. (orig.)

Baryon acoustic signature in the clustering of density maxima

International Nuclear Information System (INIS)

Desjacques, Vincent

2008-01-01

We reexamine the two-point correlation of density maxima in Gaussian initial conditions. Spatial derivatives of the linear density correlation, which were ignored in the calculation of Bardeen et al.[Astrophys. J. 304, 15 (1986)], are included in our analysis. These functions exhibit large oscillations around the sound horizon scale for generic cold dark matter (CDM) power spectra. We derive the exact leading-order expression for the correlation of density peaks and demonstrate the contribution of those spatial derivatives. In particular, we show that these functions can modify significantly the baryon acoustic signature of density maxima relative to that of the linear density field. The effect depends upon the exact value of the peak height, the filter shape and size, and the small-scale behavior of the transfer function. In the ΛCDM cosmology, for maxima identified in the density field smoothed at mass scale M≅10 12 -10 14 M · /h and with linear threshold height ν=1.673/σ(M), the contrast of the baryon acoustic oscillations (BAO) can be a few tens of percent larger than in the linear matter correlation. Overall, the BAO is amplified for ν > or approx. 1 and damped for ν < or approx. l 1. Density maxima thus behave quite differently than linearly biased tracers of the density field, whose acoustic signature is a simple scaled version of the linear baryon acoustic oscillation. We also calculate the mean streaming of peak pairs in the quasilinear regime. We show that the leading-order 2-point correlation and pairwise velocity of density peaks are consistent with a nonlinear, local biasing relation involving gradients of the density field. Biasing will be an important issue in ascertaining how much of the enhancement of the BAO in the primeval correlation of density maxima propagates into the late-time clustering of galaxies.

SU-E-I-55: The Contribution to Skin Dose Due to Scatter From the Patient Table and the Head Holder During Fluoroscopy

International Nuclear Information System (INIS)

Islam, N; Xiong, Z; Vijayan, S; Rudin, S; Bednarek, D

2015-01-01

Purpose: To determine contributions to skin dose due to scatter from the table and head holder used during fluoroscopy, and also to explore alternative design material to reduce the scatter dose. Methods: Measurements were made of the primary and scatter components of the xray beam exiting the patient table and a cylindrical head holder used on a Toshiba Infinix c-arm unit as a function of kVp for the various beam filters on the machine and for various field sizes. The primary component of the beam was measured in air with the object placed close to the x-ray tube with an air gap between it and a 6 cc parallel-plate ionization chamber and with the beam collimated to a size just larger than the chamber. The primary plus scatter radiation components were measured with the object moved to a position in the beam next to the chamber for larger field sizes. Both sets of measurements were preformed while keeping the source-to-chamber distance fixed. The scatter fraction was estimated by taking the ratio of the difference between the two measurements and the reading that included both primary and scatter. Similar measurements were also made for a 2.3 cm thick Styrofoam block which could substitute for the patient support. Results: The measured scatter fractions indicate that the patient table as well as the head holder contributes an additional 10–16% to the patient entrance dose depending on field size. Forward scatter was reduced with the Styrofoam block so that the scatter fraction was about 4–5%. Conclusion: The results of this investigation demonstrated that scatter from the table and head holder used in clinical fluoroscopy contribute substantially to the skin dose. The lower contribution of scatter from Styrofoam suggests that there is an opportunity to redesign patient support accessories to reduce the skin dose. Partial support from NIH grant R01EB002873 and Toshiba Medical Systems Corporation Equipment Grant

SU-E-I-55: The Contribution to Skin Dose Due to Scatter From the Patient Table and the Head Holder During Fluoroscopy

Energy Technology Data Exchange (ETDEWEB)

Islam, N; Xiong, Z; Vijayan, S; Rudin, S; Bednarek, D [Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY (United States)

2015-06-15

Purpose: To determine contributions to skin dose due to scatter from the table and head holder used during fluoroscopy, and also to explore alternative design material to reduce the scatter dose. Methods: Measurements were made of the primary and scatter components of the xray beam exiting the patient table and a cylindrical head holder used on a Toshiba Infinix c-arm unit as a function of kVp for the various beam filters on the machine and for various field sizes. The primary component of the beam was measured in air with the object placed close to the x-ray tube with an air gap between it and a 6 cc parallel-plate ionization chamber and with the beam collimated to a size just larger than the chamber. The primary plus scatter radiation components were measured with the object moved to a position in the beam next to the chamber for larger field sizes. Both sets of measurements were preformed while keeping the source-to-chamber distance fixed. The scatter fraction was estimated by taking the ratio of the difference between the two measurements and the reading that included both primary and scatter. Similar measurements were also made for a 2.3 cm thick Styrofoam block which could substitute for the patient support. Results: The measured scatter fractions indicate that the patient table as well as the head holder contributes an additional 10–16% to the patient entrance dose depending on field size. Forward scatter was reduced with the Styrofoam block so that the scatter fraction was about 4–5%. Conclusion: The results of this investigation demonstrated that scatter from the table and head holder used in clinical fluoroscopy contribute substantially to the skin dose. The lower contribution of scatter from Styrofoam suggests that there is an opportunity to redesign patient support accessories to reduce the skin dose. Partial support from NIH grant R01EB002873 and Toshiba Medical Systems Corporation Equipment Grant.

Fragmentation production of Ωccc baryons at LHC energies

International Nuclear Information System (INIS)

Saleev, V.A.

2000-01-01

Within the nonrelativistic quark-diquark model for heavy baryons, the fragmentation functions for the transitions of a c-quark and a doubly charmed vector diquark into an Ω ccc baryon are calculated in the leading order of perturbative QCD. The cross section for Ω ccc production in high-energy hadron interactions is estimated. It is assumed that Ω ccc baryons are formed via the fragmentation of a c quark or a vector (cc) diquark produced in the partonic subprocesses gg → cc-bar, qq-bar → cc-bar, gg → (cc) + c-bar + c-bar, and qq-bar → (cc) + c-bar + c-bar

Exotic charmed baryon production in ultrarelativistic heavy ion collisions

International Nuclear Information System (INIS)

Zimanyi, J.; Biro, T.S.; Levai, P.

1993-01-01

The authors investigate multi-heavy baryon formation in Au + Au collision using an extended version of the combinatoric break up model for rehadronization. A penalty factor, p, is introduced to characterize the coalescence probability of a light quark with a heavy one. At LHC energy large production rate is found for certain multi-heavy baryons and mesons such as Ω ccc , Ξ cc , J/Ψ and suppression for Λ c , D. They speculate also on the possible existence of a heavy bottom-charm six-quark baryon. A semiclassical and a gaussian estimate reveal that the octet-octet bbb-cc configuration can be energetically favored with respect to the singlet-singlet one

Finite Volume Effect of Baryons in Strange Hadronic Matter

Institute of Scientific and Technical Information of China (English)

SUN Bao-Xi; LI Lei; NING Ping-Zhi; ZHAO En-Guang

2001-01-01

The finite volume effect of baryons in strange hadronic matter (SHM) is studied within the framework of relativistic mean-field theory. As this effect is concerned, the saturation density of SHM turns lower, and the binding energy per baryon decreases. Its influence to the compression modulus of SHM is also discussed.

Decays of J/psi (3100) to baryon final states

International Nuclear Information System (INIS)

Eaton, M.W.

1982-05-01

We present results for the decays of psi(3100) into baryon and hyperon final states. The sample studied here consists of 1.3 million produced psi decays. The decays into nonstrange baryons agree well with currently established results, but with better statistics. In addition, significant resonance formation in multibody final states is observed. The decay psi → anti ppγ, the first direct photon decay of the psi involving baryons in the final state, is presented and the theoretical implications of the decays are briefly explored. Several new decays of the psi involving strange baryons are explored, including the first observations of three body final states involving hyperons. The I-spin symmetry of the strong decay psi → baryons has clearly been observed. The reduced matrix elements for psi → B anti B are presented for final states of different SU(3) content. The B 8 anti B 8 results are in excellent agreement with the psi being an SU(3) singlet as are the results for psi → B 10 anti B 10 . We present the first evidence for the SU(3) violating decays of the type psi → B 8 anti B 10 + c.c.. Angular distributions for psi → B 8 anti B 8 are presented and compared with theoretical predictions. Statistics are limited, but the data tends to prefer other than a 1 + Cos 2 theta distribution

Charmed baryon production in hadronic collisions

International Nuclear Information System (INIS)

Boreskov, K.G.; Kaidalov, A.B.

1982-01-01

Quantitative description of charmed baryon production in pp and πp collisions is obtained in the framework of the soft, peripheral quark-gluon approach. The quark-gluon model, based on the topological expansion, is used for determination of the planar part of the multiperipheral diagrams. The parameters of the D*-D** Regge trajectories and residues are estimated in this model. The total contribution of the peripheral mechanism is calculated by substitution of this planar part to the cylinder-type multiperipheral diagram with π-meson exchange. The energy dependence, absolute value of the inclusive cross section for #betta#sub(c) production and its xsub(F) and psub(perpendicular)-distributions (where xsub(F) is the Feynman variable and psub(perpendicular) is transverse momentum) are calculated and found to be in an agreement with experimental data. Connection with orher models of charm production is discussed

Baryon-number generation in supersymmetric unified models: the effect of supermassive fermions

International Nuclear Information System (INIS)

Kolb, E.W.; Raby, S.

1983-01-01

In supersymmetric unified models, baryon-number-violating reactions may be mediated by supermassive fermions in addition to the usual supermassive bosons. The effective low-energy baryon-number-violating cross section for fermion-mediated reactions is sigma/sub DeltaB/approx.g 4 /m 2 , where g is a coupling constant and m is the supermassive fermion mass, as opposed to sigma/sub DeltaB/approx.g 4 s/m 4 for scalar- or vector-mediated reactions (√s is the center-of-mass energy). Since the fermion-mediated cross section is larger at low energy, it is more effective at damping the baryon number produced in decay of the supermassive particles. In this paper we calculate baryon-number generation in models with fermion-mediated baryon-number-violating reactions, and discuss implications for supersymmetric model building

Theoretical perspective for baryon number violation

International Nuclear Information System (INIS)

Langacker, P.

1982-01-01

In this talk I describe the theoretical predictions for proton decay and other baryon number violating processes, emphasizing that there are many models and theories involving baryon number violation and that it is an experimental problem to distinguish between them. I first review the the theoretical predictions for the unification mass M/sub X/ and for the weak angle sin 2 theta/sub W/. It will be seen that the class of models involving an Su 3 x SU 2 x U 1 invariant desert between M/sub W/ and M/sub X/ are strongly favored. I then turn to baryon number violation. The proton lifetime and branching ratio predictions for the SU 5 and other 3-2-1 desert models are reviewed, with emphasis on distinguishing between models and on the implications of the small value of the QCD parameter lambda/sub anti MS/ that seems to be favored by the data. I then discuss the consequences of low energy supersymmetry for proton decay, nuclear effects, and models with low mass scales. Finally, I mention possible implications of the anomalously large flux of cosmic ray antiprotons that has recently been reported

A Higgs at 125.1 GeV and baryon mass spectra derived from a Common U(3) Lie group framework

DEFF Research Database (Denmark)

Trinhammer, Ole; Bohr, Henrik; Jensen, Mogens O Stibius

2015-01-01

Baryons are described by a Hamiltonian on an intrinsic U(3) Lie group configuration space with electroweak degrees of freedom originating in specific Bloch wave factors. By opening the Bloch degrees of freedom pairwise via a U(2) Higgs mechanism, the strong and electroweak energy scales become...... related to yield the Higgs mass 125.085+/-0.017 GeV and the usual gauge boson masses. From the same Hamiltonian we derive both the relative neutron to proton mass ratio and the N and Delta mass spectra. All compare rather well with the experimental values. We predict neutral flavour baryon singlets...... to be sought for in negative pions scattering on protons or in photoproduction on neutrons and in invariant mass like Σ+c(2455)D- from various decays above the open charm threshold, e.g. at 4499, 4652 and 4723 MeV. The fundamental predictions are based on just one length scale and the fine structure coupling...

Search for narrow four-baryon states

International Nuclear Information System (INIS)

Badelek, B.

1981-01-01

Highly excited (4.10 2 ) four-baryon resonances have been searched for in the missing-mass spectrum of the reaction π - + 4 He → π - + X at 5 GeV/c in the region of small four-momentum transfer (0.005 2 ), where one of the decay products of the X is either proton or deuteron or triton. No resonance signal is seen in the mass spectrum of X. Within our limited acceptance, the cross section for the production of a narrow (GAMMA approx. 20 MeV/c 2 ) four-baryon state with mass 4.9 GeV/c 2 is estimated to be smaller than approx. 100 nb. (orig.)

Are narrow mesons, baryons and dibaryons evidence for multiquark states?

International Nuclear Information System (INIS)

Tatischeff, B.; Yonnet, J.

2000-01-01

Several narrow structures have been progressively observed since the last fifteen years, in di-baryonic invariant mass spectra or in missing mass spectra. More recently, narrow structures were observed in baryonic and now in mesonic mass spectra. Since these small peaks appear at fixed masses, independently of the experiment, they are associated with real states. There is no room to explain these states within classical nuclear physics taking into account baryonic and mesonic degrees of freedom. An interpretation is proposed, which associate these narrow structures with two coloured quark clusters. (authors)

Cloudy bag model calculation of P11 πN scattering

International Nuclear Information System (INIS)

Rinat, A.S.

1981-05-01

πN, πΔ scattering in the cloudy bag model (CBM) is considered using an elementary π field and bare bag states for N, Δ, Nsup(*)(1470). The resulting 2-channel problem is solved neglecting intermediate states with anti-baryons and states with more than a single pion. It is shown that delta 11 may be reproduced for parameters close to their theoretical values. The fit thus provides a test for the CBM. (author)

Baryonic dark matter

Science.gov (United States)

Silk, Joseph

1991-01-01

Both canonical primordial nucleosynthesis constraints and large-scale structure measurements, as well as observations of the fundamental cosmological parameters, appear to be consistent with the hypothesis that the universe predominantly consists of baryonic dark matter (BDM). The arguments for BDM to consist of compact objects that are either stellar relics or substellar objects are reviewed. Several techniques for searching for halo BDM are described.

Baryon structure from lattice QCD

International Nuclear Information System (INIS)

Alexandrou, C.

2009-01-01

We present recent lattice results on the baryon spectrum, nucleon electromagnetic and axial form factors, nucleon to Δ transition form factors as well as the Δ electromagnetic form factors. The masses of the low lying baryons and the nucleon form factors are calculated using two degenerate flavors of twisted mass fermions down to pion mass of about 270 MeV. We compare to the results of other collaborations. The nucleon to Δ transition and Δ form factors are calculated in a hybrid scheme, which uses staggered sea quarks and domain wall valence quarks. The dominant magnetic dipole nucleon to Δ transition form factor is also evaluated using dynamical domain wall fermions. The transverse density distributions of the Δ in the infinite momentum frame are extracted using the form factors determined from lattice QCD. (author)

Baryons on the lattice

International Nuclear Information System (INIS)

Bali, G.S.

2005-01-01

I comment on progress of lattice QCD techniques and calculations. Recent results on pentaquark masses as well as of the spectrum of excited baryons are summarized and interpreted. The present state of calculations of quantities related to the nucleon structure and of electromagnetic transition form factors is surveyed

Dilepton as a signature for the baryon-rich quark-gluon matter

International Nuclear Information System (INIS)

Zejun He; Jiaju Zhang

1995-01-01

From the full stopping scenario, we study dilepton production in a baryon rich quark-gluon fireball on the basis of a relativistic hydrodynamic model, and find that with increasing initial baryon density a characteristic valley and a subsequent peak, which more uniquely signal the formation of the baryon-rich quark-gluon matter, appear in the total dilepton yield. Such characteristics can be tested in future experiments at CERN and Brookhaven. (author). Letter-to-the-editor

Missing baryonic resonances in the Hagedorn spectrum

Energy Technology Data Exchange (ETDEWEB)

Man Lo, Pok [University of Wroclaw, Institute of Theoretical Physics, Wroclaw (Poland); GSI, Extreme Matter Institute EMMI, Darmstadt (Germany); Marczenko, Michal; Sasaki, Chihiro [University of Wroclaw, Institute of Theoretical Physics, Wroclaw (Poland); Redlich, Krzysztof [University of Wroclaw, Institute of Theoretical Physics, Wroclaw (Poland); GSI, Extreme Matter Institute EMMI, Darmstadt (Germany); Duke University, Department of Physics, Durham, NC (United States)

2016-08-15

The hadronic medium of QCD is modeled as a gas of point-like hadrons, with its composition determined by the Hagedorn mass spectrum. The spectrum consists of a discrete and a continuous part. The former is determined by the experimentally confirmed resonances tabulated by the Particle Data Group (PDG), while the latter can be extracted from the existing lattice data. This formulation of the hadron resonance gas (HRG) provides a transparent framework to relate the fluctuation of conserved charges as calculated in the lattice QCD approach to the particle content of the medium. A comparison of the two approaches shows that the equation of state is well described by the standard HRG model, which includes only a discrete spectrum of known hadrons. The corresponding description in the strange sector, however, shows clear discrepancies, thus a continuous spectrum is added to incorporate the effect of missing resonances. We propose a method to extract the strange-baryon spectrum from the lattice data. The result is consistent with the trend set by the unconfirmed strange baryons resonances listed by the PDG, suggesting that most of the missing interaction strength for the strange baryons reside in the S = 1 sector. This scenario is also supported by recent lattice calculations, and might be important in the energy region covered by the NICA accelerator in Dubna, where in the heavy-ion collisions, baryons are the dominating degrees of freedom in the final state. (orig.)

Factorization of heavy-to-light baryonic transitions in SCET

Energy Technology Data Exchange (ETDEWEB)

Wang, Wei

2011-12-15

In the framework of the soft-collinear effective theory, we demonstrate that the leading-power heavy-to-light baryonic form factors at large recoil obey the heavy quark and large energy symmetries. Symmetry breaking effects have several origins but all of them are suppressed by {lambda}/m{sub b} or {lambda}/E, where {lambda} is the hadronic scale, m{sub b} is the b quark mass and E{proportional_to}m{sub b} is the energy of light baryon in the final state. Including the energy release dependence, we derive the scaling law for form factors {xi}{sub {lambda}}{sub ,p}{proportional_to}{lambda}{sup 2} /E{sup 2}, which is in accordance with the implication from the experimental measurement on the branching ratio of {lambda}{sub b} {yields} p{pi}{sup -}. At leading order in {alpha}{sub s}, the leading-power baryonic form factors can factorize into the soft and collinear matrix elements without encountering any divergence. A leading-power factorization formula for nonleptonic b-baryon decays is also established. (orig.)

Insight into the baryon-gravity relation in galaxies

International Nuclear Information System (INIS)

Famaey, Benoit; Gentile, Gianfranco; Bruneton, Jean-Philippe; Zhao Hongsheng

2007-01-01

Observations of spiral galaxies strongly support a one-to-one analytical relation between the inferred gravity of dark matter at any radius and the enclosed baryonic mass. It is baffling that baryons manage to settle the dark matter gravitational potential in such a precise way, leaving no 'messy' fingerprints of the merging events and 'gastrophysical' feedbacks expected in the history of a galaxy in a concordance Universe. This correlation of gravity with baryonic mass can be interpreted from several nonstandard angles, especially as a modification of gravity called TeVeS, in which no galactic dark matter is needed. In this theory, the baryon-gravity relation is captured by the dieletric-like function μ of modified Newtonian dynamics (MOND), controlling the transition from 1/r 2 attraction in the strong gravity regime to 1/r attraction in the weak regime. Here, we study this μ-function in detail. We investigate the observational constraints upon it from fitting galaxy rotation curves, unveiling the degeneracy between the stellar mass-to-light ratio and the μ-function as well as the importance of the sharpness of transition from the strong to weak gravity regimes. We also numerically address the effects of nonspherical baryon geometry in the framework of nonlinear TeVeS, and exhaustively examine how the μ-function connects with the free function of that theory. In that regard, we exhibit the subtle effects and wide implications of renormalizing the gravitational constant. We finally present a discontinuity-free transition between quasistatic galaxies and the evolving Universe for the free function of TeVeS, inevitably leading to a return to 1/r 2 attraction at very low accelerations in isolated galaxies

Quantization State of Baryonic Mass in Clusters of Galaxies

Directory of Open Access Journals (Sweden)

Potter F.

2007-01-01

Full Text Available The rotational velocity curves for clusters of galaxies cannot be explained by Newtonian gravitation using the baryonic mass nor does MOND succeed in reducing this discrepancy to acceptable differences. The dark matter hypothesis appears to offer a solution; however, non-baryonic dark matter has never been detected. As an alternative approach, quantum celestial mechanics (QCM predicts that galactic clusters are in quantization states determined solely by the total baryonic mass of the cluster and its total angular momentum. We find excellent agreement with QCM for ten galactic clusters, demonstrating that dark matter is not needed to explain the rotation velocities and providing further support to the hypothesis that all gravitationally bound systems have QCM quantization states.

Physical properties of the chiral quantum baryon

International Nuclear Information System (INIS)

Mignaco, A.J.; Wulck, S.

1989-01-01

It is presented an account to understand the quantum chiral baryon, which a stable chiral soliton with baryon number one obtained after first quantization by collective coordinates. Starting from the exact series solution to the non-linear sigma model with the hedge-hog configuration, the values of several physical quantities (mass, axial weak coupling, gyromagnetic ratios and radii) as a function of the order of Pade approximants used as approximanted representations of the solution, are calculated. It turns out that consistent results may be obtained, but a better approximation should be developed. (author) [pt

Non-baryonic dark matter

OpenAIRE

Berezinsky, Veniamin Sergeevich; Bottino, A; Mignola, G

1996-01-01

The best particle candidates for non--baryonic cold dark matter are reviewed, namely, neutralino, axion, axino and Majoron. These particles are considered in the context of cosmological models with the restrictions given by the observed mass spectrum of large scale structures, data on clusters of galaxies, age of the Universe etc.

Some topics in grand unified models and the cosmological baryon asymmetry

International Nuclear Information System (INIS)

Reiss, D.B.

1981-01-01

In part I of this thesis some of the parameters relevant to the production of a cosmological baryon number asymmetry are considered in the context of grand unified models. General expressions for the average baryon number generated in the free decays of bosons are derived. The CP violation necessary for the generation of a baryon excess is discussed for a variety of SU(5) models. The kinematics of baryon number production in an illustrative SO(10) model is discussed in detail. In part II a viable SO(10) model is constructed which reproduces the phenomenological fermion mass and mixing angle values. A detailed discussion of the beta function for this model is presented. This analysis includes the effects of scalars

The search for exotic baryons at the HERMES experiment

International Nuclear Information System (INIS)

Deconinck, Wouter

2008-07-01

One of the interesting questions of Quantum Chromodynamics, the theory that governs the interactions between quarks and gluons, has been whether it is possible to observe hadrons which can not be explained as a combination of only two or three valence quarks. In numerous searches the existence of these exotic hadrons could not be confirmed. Recently, calculations based on the quark soliton model predicted the narrow exotic baryons Θ + and Ξ -- . A narrow resonance identified as the Θ + was observed by several experiments at the predicted mass of 1540 MeV, but later followed by several dedicated experiments that could not confirm these positive results. At the HERMES experiment a search for the quasi-real photoproduction of the exotic baryon Θ + on a deuterium target and the subsequent decay through pK 0 S → pπ + π - revealed a narrow resonance in the pK 0 S invariant mass distribution at 1528 MeV. In the search for the corresponding antiparticle Ξ -- the result is consistent with zero events. In this thesis we present the search for the exotic baryon Ξ -- on a deuterium target in the data sample used for the observation of the Θ + . An upper limit on the cross section of the exotic baryon Ξ -- is determined. The search for the exotic baryon Θ + on hydrogen and deuterium targets at the HERMES experiment is extensively discussed. The event mixing method can be used to estimate the distribution of background events. Several difficulties with this method were addressed, but the background description in the case of the exotic baryon Θ + remains unconvincing. Between the years 2002 and 2005 the HERMES experiment operated with a magnetic holding field around the hydrogen target. A method for the reconstruction of displaced vertices in this field was developed. The data collected during the years 2006 and 2007 offer an integrated luminosity that is several times higher than in previous data sets. After investigating all data sets collected with the HERMES

Mass spectrum of low-lying baryons in the ground state in a relativistic potential model of independent quarks with chiral symmetry

International Nuclear Information System (INIS)

Barik, N.; Dash, B.K.

1986-01-01

Under the assumption that baryons are an assembly of independent quarks, confined in a first approximation by an effective potential U(r) = 1/2(1+γ 0 )(ar 2 +V 0 ) which presumably represents the nonperturbative gluon interactions, the mass spectrum of the low-lying ground-state baryons has been calculated by considering perturbatively the contributions of the residual quark-pion coupling arising out of the requirement of chiral symmetry and that of the quark-gluon coupling due to one-gluon exchange over and above the necessary center-of-mass correction. The physical masses of the baryons so obtained agree quite well with the corresponding experimental value. The strong coupling constant α/sub c/ = 0.58 required here to describe the QCD mass splittings is quite consistent with the idea of treating one-gluon-exchange effects in lowest-order perturbation theory

Baryonic pinching of galactic dark matter halos

International Nuclear Information System (INIS)

Gustafsson, Michael; Fairbairn, Malcolm; Sommer-Larsen, Jesper

2006-01-01

High resolution cosmological N-body simulations of four galaxy-scale dark matter halos are compared to corresponding N-body/hydrodynamical simulations containing dark matter, stars and gas. The simulations without baryons share features with others described in the literature in that the dark matter density slope continuously decreases towards the center, with a density ρ DM ∝r -1.3±0.2 , at about 1% of the virial radius for our Milky Way sized galaxies. The central cusps in the simulations which also contain baryons steepen significantly, to ρ DM ∝r -1.9±0.2 , with an indication of the inner logarithmic slope converging. Models of adiabatic contraction of dark matter halos due to the central buildup of stellar/gaseous galaxies are examined. The simplest and most commonly used model, by Blumenthal et al., is shown to overestimate the central dark matter density considerably. A modified model proposed by Gnedin et al. is tested and it is shown that, while it is a considerable improvement, it is not perfect. Moreover, it is found that the contraction parameters in their model not only depend on the orbital structure of the dark-matter-only halos but also on the stellar feedback prescription which is most relevant for the baryonic distribution. Implications for dark matter annihilation at the galactic center are discussed and it is found that, although our simulations show a considerable reduced dark matter halo contraction as compared to the Blumenthal et al. model, the fluxes from dark matter annihilation are still expected to be enhanced by at least a factor of a hundred, as compared to dark-matter-only halos. Finally, it is shown that, while dark-matter-only halos are typically prolate, the dark matter halos containing baryons are mildly oblate with minor-to-major axis ratios of c/a=0.73±0.11, with their flattening aligned with the central baryonic disks

The contribution to surface dose form air scatter in mega voltage photon beams

International Nuclear Information System (INIS)

Carolan, M.G.; Butson, M.; Metcalfe, P.

1996-01-01

Full text: The minimisation of surface dose is an important requirement in radiotherapy in order to avoid undesirable skin reactions. For this reason significant effort has been expended to avoid and understand photon and electron scatter in the heads of linear accelerators which may contribute to surface dose. In this study we have examined the contribution to surface dose which arises due to scatter in the air above the patient. Experimental investigations of air contributions are difficult to design and execute. Therefore we have used Monte Carlo calculations to determine the effect that the presence of air has on surface dose. Methods: The Los Alamos Monte Carlo Neutron and Photon transport code, MCNP4A which incorporates the ETRAN electron transport code from the Integrated TIGER Series of codes was used for our simulations. The geometry used in the model was a 30 cm cube of water. The dose was tallied in cylindrical elements of 7 cm diameter along the axis of the photon beam. For the first millimetre along the beam axis in the phantom, the dose was determined at 0.1 mm increments in 0.1 mm thick volumes. For depths between 1.0 mm and 15.0 mm the dose was determined every 1 mm in 1 mm cylindrical volumes. This yields a depth dose profile with fine spatial resolution near the phantom surface. Dose was also tallied at depths of 5.0, 10.0, 15.0 and 20.0 cm. The simulations were done assuming a 6 MV photon source with a diameter of 1.5 cm, a gaussian intensity profile and a photon energy spectrum based on Mohan et al. (Med. Phys. 12 (1985) 592). No accelerator head geometry was modelled. The field size was defined by virtual collimators which were simply thin regions of zero photon importance and therefore do not contribute to photon or electron scatter. All simulations were run for sufficient particle histories (∼2x10 7 - 5x10 7 source photons) to give statistical uncertainties of ≤ 10% and in most cases ≤ 5%. Fields of size 10, 15, 20 and 25 cm were used

Heavy baryons in the heavy quark effective theory

International Nuclear Information System (INIS)

Koerner, J.G.; Thompson, G.

1991-10-01

We give a mini-review of recent results on current-induced transitions between heavy baryons (and between heavy and light baryons) in the light of the new spin and flavour symmetries of the Heavy Quark Effective Theory (HQET). We discuss the structure of the 1/m corrections to the heavy mass limit and outline a diagrammatic proof that there are no 0(1/m) correction to the Voloshin-Shifman normalization condition at zero recoil. (orig.)

Charmed and beauty baryon in hyper central model

International Nuclear Information System (INIS)

Patel, Bhavin; Vinodkumar, P.C.; Rai, Ajay Kumar

2006-01-01

For the present study the hyper central description of the three-body problem has been employed for the baryons constituting one or more charm and beauty quarks. The confinement potential is assumed in the hyper central co-ordinates as hyper central coulomb plus power potential. The charm and beauty baryons under this potential has been studied for different power indices starting from 0.5 to 2.0. The methods and results are briefly described

Charm baryon production in pp and p-Pb collisions with ALICE

CERN Multimedia

CERN. Geneva

2018-01-01

The measurement of inclusive open heavy-flavour production in pp collisions is an important test of perturbative QCD calculations, and also offers a direct way to study non-perturbative QCD processes. Charmed baryon production measurements, in particular, are useful to address the hadronisation of charm quarks. Measurements in pp and p-Pb collisions also provide a baseline for Pb-Pb collisions, where the baryon-to-meson ratios will offer a unique probe of charm thermalisation and hadronisation mechanisms in the Quark-Gluon Plasma. The production of D0, D+, D*+ and Ds mesons has been measured with ALICE in pp collisions at the LHC at several collision energies, and was found to be compatible with expectations from theory. In this talk, recent measurements of Λc+ and Ξc0 baryon production in pp collisions at a centre-of-mass energy of 7 TeV and Λc+ baryon production in p-Pb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV will be presented. The reconstruction of charmed baryons at central ...

Search for low mass exotic baryons in one pion electroproduction data measured at JLAB

International Nuclear Information System (INIS)

Tatischeff, B.; Tomasi-Gustafsson, E.

2007-02-01

This paper aims to give further evidence for the existence of low mass exotic baryons. Narrow structures in baryonic missing mass or baryonic invariant mass were previously observed during the last ten years. Since their existence is sometimes questionable, the structure functions of one pion electroproduction cross sections, measured at JLAB, are studied to add information on the possible existence of these narrow exotic baryonic resonances. (authors)

Galaxy Formation by Cosmic Strings and Cooling of Baryonic Matter

OpenAIRE

Mizuo, IZAWA; Humitaka, SATO; Department of Physics, University of Tokyo; Department of Physics, Kyoto University

1987-01-01

Cooling and contraction of baryonic matter are investigated ina galaxy formation scenario by string loops. It is found that ～3% of virialized baryonic matter has cooled down and contracted. This virialized object may have a disk-halo structure and be considered a galaxy.

An investigation of triply heavy baryon production at hadron colliders

CERN Document Server

Gomshi Nobary, M A

2006-01-01

The triply heavy baryons have a rather diverse mass range. While some of them possess considerable production rates at existing facilities, others need to be produced at future high energy colliders. Here we study the direct fragmentation production of the Ωccc and Ωbbb baryons as the prototypes of triply heavy baryons at the hadron colliders with different . We present and compare the transverse momentum distributions of the differential cross sections, distributions of total cross sections and the integrated total cross sections of these states at the RHIC, the Tevatron Run II and the CERN LHC.

A new baryonic equation of state at sub-nuclear densities for core-collapse simulations

International Nuclear Information System (INIS)

Furusawa, Shun; Yamada, Shoichi; Sumiyoshi, Kohsuke; Suzuki, Hideyuki

2012-01-01

We construct a new equation of state for baryons at sub-nuclear densities for the use in core-collapse simulations of massive stars. The formulation is based on the nuclear statistical equilibrium description and the liquid drop approximation of nuclei. The model free energy to minimize is calculated by using relativistic mean field theory for nucleons and the mass formula for nuclei with atomic number up to ∼ 1000. We have also taken into account the pasta phase. We find that the free energy and other thermodynamical quantities are not very different from those given in the standard EOSs that adopt the single nucleus approximation. On the other hand, the average mass is systematically different, which may have an important effect to the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. It is also interesting that the root mean square of the mass number is not very different from the average mass number, since the former is important for the evaluation of coherent scattering rates on nuclei but has been unavailable so far.

A new baryonic equation of state at sub-nuclear densities for core-collapse simulations

Science.gov (United States)

Furusawa, Shun; Yamada, Shoichi; Sumiyoshi, Kohsuke; Suzuki, Hideyuki

2012-11-01

We construct a new equation of state for baryons at sub-nuclear densities for the use in core-collapse simulations of massive stars. The formulation is based on the nuclear statistical equilibrium description and the liquid drop approximation of nuclei. The model free energy to minimize is calculated by using relativistic mean field theory for nucleons and the mass formula for nuclei with atomic number up to ~ 1000. We have also taken into account the pasta phase. We find that the free energy and other thermodynamical quantities are not very different from those given in the standard EOSs that adopt the single nucleus approximation. On the other hand, the average mass is systematically different, which may have an important effect to the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. It is also interesting that the root mean square of the mass number is not very different from the average mass number, since the former is important for the evaluation of coherent scattering rates on nuclei but has been unavailable so far.

A new baryonic equation of state at sub-nuclear densities for core-collapse simulations

Energy Technology Data Exchange (ETDEWEB)

Furusawa, Shun; Yamada, Shoichi; Sumiyoshi, Kohsuke; Suzuki, Hideyuki [Department of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Department of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan) and Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan); Faculty of Science and Technology, Tokyo University of Science, Yamazaki 2641, Noda, Chiba 278-8510 (Japan)

2012-11-12

We construct a new equation of state for baryons at sub-nuclear densities for the use in core-collapse simulations of massive stars. The formulation is based on the nuclear statistical equilibrium description and the liquid drop approximation of nuclei. The model free energy to minimize is calculated by using relativistic mean field theory for nucleons and the mass formula for nuclei with atomic number up to {approx} 1000. We have also taken into account the pasta phase. We find that the free energy and other thermodynamical quantities are not very different from those given in the standard EOSs that adopt the single nucleus approximation. On the other hand, the average mass is systematically different, which may have an important effect to the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. It is also interesting that the root mean square of the mass number is not very different from the average mass number, since the former is important for the evaluation of coherent scattering rates on nuclei but has been unavailable so far.

Baryonic Force for Accelerated Cosmic Expansion and Generalized U1b Gauge Symmetry in Particle-Cosmology

Directory of Open Access Journals (Sweden)

Khan Mehbub

2018-01-01

Full Text Available Based on baryon charge conservation and a generalized Yang-Mills symmetry for Abelian (and non-Abelian groups, we discuss a new baryonic gauge field and its linear potential for two point-like baryon charges. The force between two point-like baryons is repulsive, extremely weak and independent of distance. However, for two extended baryonic systems, we have a dominant linear force α r. Thus, only in the later stage of the cosmic evolution, when two baryonic galaxies are separated by an extremely large distance, the new repulsive baryonic force can overcome the gravitational attractive force. Such a model provides a gauge-field-theoretic understanding of the late-time accelerated cosmic expansion. The baryonic force can be tested by measuring the accelerated Wu-Doppler frequency shifts of supernovae at different distances.

Extracting $p\\Lambda$ scattering lengths from heavy ion collisions

CERN Document Server

Shapoval, V M; Lednicky, R; Sinyukov, Yu M

2015-01-01

The $p-\\Lambda \\oplus \\bar{p}-\\bar{\\Lambda}$ and $\\bar{p}-\\Lambda \\oplus p-\\bar{\\Lambda}$ correlation functions for 10% most central Au+Au collisions at top RHIC energy $\\sqrt{s_{NN}}=200$ GeV are modeled with Lednicky and Lyuboshitz analytical formula using the source radii extracted from the hydrokinetic model (HKM) simulations. For the baryon-antibaryon case the corresponding spin-averaged strong interaction scattering length is obtained by fitting the STAR correlation function. In contrast to the experimental results, where extracted $p\\bar{\\Lambda}$ source radius value was found $\\sim 2$ times smaller than the corresponding $p\\Lambda$ one, the calculations in HKM show both $p\\Lambda$ and $p\\bar{\\Lambda}$ effective source radii to be quite close, as expected from theoretical considerations. To obtain the satisfactory fit to the measured baryon-antibaryon correlation function at this large source radius value, the modified analytical approximation to the correlation function, effectively accounting for the...

Repulsive baryonic interactions and lattice QCD observables at imaginary chemical potential

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Volodymyr Vovchenko

2017-12-01

Full Text Available The first principle lattice QCD methods allow to calculate the thermodynamic observables at finite temperature and imaginary chemical potential. These can be compared to the predictions of various phenomenological models. We argue that Fourier coefficients with respect to imaginary baryochemical potential are sensitive to modeling of baryonic interactions. As a first application of this sensitivity, we consider the hadron resonance gas (HRG model with repulsive baryonic interactions, which are modeled by means of the excluded volume correction. The Fourier coefficients of the imaginary part of the net-baryon density at imaginary baryochemical potential – corresponding to the fugacity or virial expansion at real chemical potential – are calculated within this model, and compared with the Nt=12 lattice data. The lattice QCD behavior of the first four Fourier coefficients up to T≃185 MeV is described fairly well by an interacting HRG with a single baryon–baryon eigenvolume interaction parameter b≃1 fm3, while the available lattice data on the difference χ2B−χ4B of baryon number susceptibilities is reproduced up to T≃175 MeV. Keywords: Hadron resonance gas, Excluded volume, Imaginary chemical potential

Baryon magnetic moments: Symmetries and relations

Energy Technology Data Exchange (ETDEWEB)

Parreno, Assumpta [University of Barcelona; Savage, Martin [Univ. of Washington, Seattle, WA (United States); Tiburzi, Brian [City College of New York, NY (United States); City Univ. (CUNY), NY (United States); Wilhelm, Jonas [Justus-Liebig-Universitat Giessen, Giessen, Germany; Univ. of Washington, Seattle, WA (United States); Chang, Emmanuel [Univ. of Washington, Seattle, WA (United States); Detmold, William [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Orginos, Kostas [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2018-04-01

Magnetic moments of the octet baryons are computed using lattice QCD in background magnetic fields, including the first treatment of the magnetically coupled Σ0- Λ system. Although the computations are performed for relatively large values of the up and down quark masses, we gain new insight into the symmetries and relations between magnetic moments by working at a three-flavor mass-symmetric point. While the spinflavor symmetry in the large Nc limit of QCD is shared by the naïve constituent quark model, we find instances where quark model predictions are considerably favored over those emerging in the large Nc limit. We suggest further calculations that would shed light on the curious patterns of baryon magnetic moments.

Baryon physics in holographic QCD

Directory of Open Access Journals (Sweden)

Alex Pomarol

2009-03-01

Full Text Available In a simple holographic model for QCD in which the Chern–Simons term is incorporated to take into account the QCD chiral anomaly, we show that baryons arise as stable solitons which are the 5D analogs of 4D skyrmions. Contrary to 4D skyrmions and previously considered holographic scenarios, these solitons have sizes larger than the inverse cut-off of the model, and therefore they are predictable within our effective field theory approach. We perform a numerical determination of several static properties of the nucleons and find a satisfactory agreement with data. We also calculate the amplitudes of “anomalous” processes induced by the Chern–Simons term in the meson sector, such as ω→πγ and ω→3π. A combined fit to baryonic and mesonic observables leads to an agreement with experiments within 16%.

What can we learn from unpolarized and polarized electroproduction of fast baryons

International Nuclear Information System (INIS)

Artru, X.

1991-01-01

Two applications of semi-inclusive electroproduction of fast baryons are presented: (i) The steepness of the baryon spectrum at medium rapidity can give information about the general mechanisms of baryon production in soft and hard processes. (ii) With a polarized target and a detector which analyses the polarization of final Λ's, the aptitude of quarks to carry transverse polarization can be tested for the first time

Isgur-Wise Function and Polarization Characteristics of Λb-Baryon

International Nuclear Information System (INIS)

Ivanov, M.A.; Lyubovitskij, V.E.

1994-01-01

In connection with planned experiments devoted to investigation of semileptonic decays of beauty baryons Isgur-Wise function and polarization characteristics of Λ b baryon are calculated in the framework of diquark model with taking into account of infrared behaviour of heavy quark. (author). 4 figs., 3 tabs

Elucidating the contribution of Rayleigh scattering to the bluish appearance of veins

Science.gov (United States)

Van Leeuwen, Spencer R.; Baranoski, Gladimir V. G.

2018-02-01

The bluish appearance of veins located immediately beneath the skin has long been a topic of interest for biomedical optics researchers. Despite this interest, a thorough identification of the specific optical processes responsible for this phenomenon remains to be achieved. We employ controlled in silico experiments to address this enduring open problem. Our experiments, which are supported by measured data available in the scientific literature, are performed using first-principles models of light interaction with human skin and blood. Using this investigation approach, we quantitatively demonstrate that Rayleigh scattering caused by collagen fibrils present in the papillary dermis, a sublayer of the skin, can play a pivotal role in the bluish appearance of veins as suggested by previous works in this area. Moreover, also taking color perception aspects into account, we systematically assess the effects of variations in fibril radius and papillary dermis thickness on the coloration of veins under different illuminants. Notably, this assessment indicates that Rayleigh scattering elicited by reticulin fibrils, another type of fibril found in the papillary dermis, is unlikely to significantly contribute to the bluish appearance of veins. By strengthening the current understanding of light attenuation mechanisms affecting the appearance of skin and blood, our investigation contributes to the development of more effective technologies aimed at the noninvasive measurement of the physiological properties of these tissues.

The dark-baryonic matter mass relation for observational verification in Verlinde's emergent gravity

Science.gov (United States)

Shen, Jian Qi

2018-06-01

Recently, a new interesting idea of origin of gravity has been developed by Verlinde. In this scheme of emergent gravity, where horizon entropy, microscopic de Sitter states and relevant contribution to gravity are involved, an entropy displacement resulting from matter behaves as a memory effect and can be exhibited at sub-Hubble scales, namely, the entropy displacement and its "elastic" response would lead to emergent gravity, which gives rise to an extra gravitational force. Then galactic dark matter effects may origin from such extra emergent gravity. We discuss some concepts in Verlinde's theory of emergent gravity and point out some possible problems or issues, e.g., the gravitational potential caused by Verlinde's emergent apparent dark matter may no longer be continuous in spatial distribution at ordinary matter boundary (such as a massive sphere surface). In order to avoid the unnatural discontinuity of the extra emergent gravity of Verlinde's apparent dark matter, we suggest a modified dark-baryonic mass relation (a formula relating Verlinde's apparent dark matter mass to ordinary baryonic matter mass) within this framework of emergent gravity. The modified mass relation is consistent with Verlinde's result at relatively small scales (e.g., R3h_{70}^{-1} Mpc), the modified dark-baryonic mass relation presented here might be in better agreement with the experimental curves of weak lensing analysis in the recent work of Brouwer et al. Galactic rotation curves are compared between Verlinde's emergent gravity and McGaugh's recent model of MOND (Modified Newtonian Dynamics established based on recent galaxy observations). It can be found that Verlinde rotational curves deviate far from those of McGaugh MOND model when the MOND effect (or emergent dark matter) dominates. Some applications of the modified dark-baryonic mass relation inspired by Verlinde's emergent gravity will be addressed for galactic and solar scales. Potential possibilities to test this dark-baryonic

Tidal Dwarf Galaxies and Missing Baryons

Directory of Open Access Journals (Sweden)

Frederic Bournaud

2010-01-01

Full Text Available Tidal dwarf galaxies form during the interaction, collision, or merger of massive spiral galaxies. They can resemble “normal” dwarf galaxies in terms of mass, size, and become dwarf satellites orbiting around their massive progenitor. They nevertheless keep some signatures from their origin, making them interesting targets for cosmological studies. In particular, they should be free from dark matter from a spheroidal halo. Flat rotation curves and high dynamical masses may then indicate the presence of an unseen component, and constrain the properties of the “missing baryons,” known to exist but not directly observed. The number of dwarf galaxies in the Universe is another cosmological problem for which it is important to ascertain if tidal dwarf galaxies formed frequently at high redshift, when the merger rate was high, and many of them survived until today. In this paper, “dark matter” is used to refer to the nonbaryonic matter, mostly located in large dark halos, that is, CDM in the standard paradigm, and “missing baryons” or “dark baryons” is used to refer to the baryons known to exist but hardly observed at redshift zero, and are a baryonic dark component that is additional to “dark matter”.

arXiv Search for baryon-number-violating $\\Xi_b^0$ oscillations

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Aaij, Roel; LHCb Collaboration; Adinolfi, Marco; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Alfonso Albero, Alejandro; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Archilli, Flavio; d'Argent, Philippe; Arnau Romeu, Joan; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Babuschkin, Igor; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baker, Sophie; Balagura, Vladislav; Baldini, Wander; Baranov, Alexander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Baryshnikov, Fedor; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Beiter, Andrew; Bel, Lennaert; Beliy, Nikita; Bellee, Violaine; Belloli, Nicoletta; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Beranek, Sarah; Berezhnoy, Alexander; Bernet, Roland; Berninghoff, Daniel; Bertholet, Emilie; Bertolin, Alessandro; Betancourt, Christopher; Betti, Federico; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bezshyiko, Iaroslava; Bifani, Simone; Billoir, Pierre; Birnkraut, Alex; Bitadze, Alexander; Bizzeti, Andrea; Bjørn, Mikkel; Blake, Thomas; Blanc, Frederic; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Boettcher, Thomas; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Bordyuzhin, Igor; Borgheresi, Alessio; Borghi, Silvia; Borisyak, Maxim; Borsato, Martino; Bossu, Francesco; Boubdir, Meriem; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Britton, Thomas; Brodzicka, Jolanta; Brundu, Davide; Buchanan, Emma; Burr, Christopher; Bursche, Albert; Buytaert, Jan; Byczynski, Wiktor; Cadeddu, Sandro; Cai, Hao; Calabrese, Roberto; Calladine, Ryan; Calvi, Marta; Calvo Gomez, Miriam; Camboni, Alessandro; Campana, Pierluigi; Campora Perez, Daniel Hugo; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cavallero, Giovanni; Cenci, Riccardo; Chamont, David; Charles, Matthew; Charpentier, Philippe; Chatzikonstantinidis, Georgios; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu Faye; Chitic, Stefan-Gabriel; Chobanova, Veronika; Chrzaszcz, Marcin; Chubykin, Alexsei; Ciambrone, Paolo; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collins, Paula; Colombo, Tommaso; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombs, George; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Costa Sobral, Cayo Mar; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Currie, Robert; D'Ambrosio, Carmelo; Da Cunha Marinho, Franciole; Dall'Occo, Elena; Dalseno, Jeremy; Davis, Adam; De Aguiar Francisco, Oscar; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Serio, Marilisa; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Del Buono, Luigi; Dembinski, Hans Peter; Demmer, Moritz; Dendek, Adam; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Nezza, Pasquale; Dijkstra, Hans; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Douglas, Lauren; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Durante, Paolo; Dzhelyadin, Rustem; Dziewiecki, Michal; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Ebert, Marcus; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Farley, Nathanael; Farry, Stephen; Fazzini, Davide; Federici, Luca; Ferguson, Dianne; Fernandez, Gerard; Fernandez Declara, Placido; Fernandez Prieto, Antonio; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fini, Rosa Anna; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fleuret, Frederic; Fohl, Klaus; Fontana, Marianna; Fontanelli, Flavio; Forshaw, Dean Charles; Forty, Roger; Franco Lima, Vinicius; Frank, Markus; Frei, Christoph; Fu, Jinlin; Funk, Wolfgang; Furfaro, Emiliano; Färber, Christian; Gabriel, Emmy; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; Garcia Martin, Luis Miguel; García Pardiñas, Julián; Garra Tico, Jordi; Garrido, Lluis; Garsed, Philip John; Gascon, David; Gaspar, Clara; Gavardi, Laura; Gazzoni, Giulio; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianì, Sebastiana; Gibson, Valerie; Girard, Olivier Göran; Giubega, Lavinia-Helena; Gizdov, Konstantin; Gligorov, Vladimir; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gorelov, Igor Vladimirovich; Gotti, Claudio; Govorkova, Ekaterina; Grabowski, Jascha Peter; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graverini, Elena; Graziani, Giacomo; Grecu, Alexandru; Greim, Roman; Griffith, Peter; Grillo, Lucia; Gruber, Lukas; Gruberg Cazon, Barak Raimond; Grünberg, Oliver; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Göbel, Carla; Hadavizadeh, Thomas; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hamilton, Brian; Han, Xiaoxue; Hancock, Thomas Henry; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; Hasse, Christoph; Hatch, Mark; He, Jibo; Hecker, Malte; Heinicke, Kevin; Heister, Arno; Hennessy, Karol; Henrard, Pierre; Henry, Louis; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hombach, Christoph; Hopchev, Plamen Hristov; Huard, Zachary; Hulsbergen, Wouter; Humair, Thibaud; Hushchyn, Mikhail; Hutchcroft, David; Ibis, Philipp; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jalocha, Pawel; Jans, Eddy; Jawahery, Abolhassan; Jiang, Feng; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kandybei, Sergii; Karacson, Matthias; Kariuki, James Mwangi; Karodia, Sarah; Kazeev, Nikita; Kecke, Matthieu; Kelsey, Matthew; Kenzie, Matthew; Ketel, Tjeerd; Khairullin, Egor; Khanji, Basem; Khurewathanakul, Chitsanu; Kirn, Thomas; Klaver, Suzanne; Klimaszewski, Konrad; Klimkovich, Tatsiana; Koliiev, Serhii; Kolpin, Michael; Komarov, Ilya; Kopecna, Renata; Koppenburg, Patrick; Kosmyntseva, Alena; Kotriakhova, Sofia; Kozeiha, Mohamad; Kravchuk, Leonid; Kreps, Michal; Krokovny, Pavel; Kruse, Florian; Krzemien, Wojciech; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kuonen, Axel Kevin; Kurek, Krzysztof; Kvaratskheliya, Tengiz; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lanfranchi, Gaia; Langenbruch, Christoph; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; Leflat, Alexander; Lefrançois, Jacques; Lefèvre, Regis; Lemaitre, Florian; Lemos Cid, Edgar; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Pei-Rong; Li, Tenglin; Li, Yiming; Li, Zhuoming; Likhomanenko, Tatiana; Lindner, Rolf; Lionetto, Federica; Lisovskyi, Vitalii; Liu, Xuesong; Loh, David; Loi, Angelo; Longstaff, Iain; Lopes, Jose; Lucchesi, Donatella; Lucio Martinez, Miriam; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Lusiani, Alberto; Lyu, Xiao-Rui; Machefert, Frederic; Maciuc, Florin; Macko, Vladimir; Mackowiak, Patrick; Maddrell-Mander, Samuel; Maev, Oleg; Maguire, Kevin; Maisuzenko, Dmitrii; Majewski, Maciej Witold; Malde, Sneha; Malinin, Alexander; Maltsev, Timofei; Manca, Giulia; Mancinelli, Giampiero; Manning, Peter Michael; Marangotto, Daniele; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marinangeli, Matthieu; Marino, Pietro; Marks, Jörg; Martellotti, Giuseppe; Martin, Morgan; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massacrier, Laure Marie; Massafferri, André; Matev, Rosen; Mathad, Abhijit; Mathe, Zoltan; Matteuzzi, Clara; Mauri, Andrea; Maurice, Emilie; Maurin, Brice; Mazurov, Alexander; McCann, Michael; McNab, Andrew; McNulty, Ronan; Mead, James Vincent; Meadows, Brian; Meaux, Cedric; Meier, Frank; Meinert, Nis; Melnychuk, Dmytro; Merk, Marcel; Merli, Andrea; Michielin, Emanuele; Milanes, Diego Alejandro; Millard, Edward James; Minard, Marie-Noelle; Minzoni, Luca; Mitzel, Dominik Stefan; Mogini, Andrea; Molina Rodriguez, Josue; Mombacher, Titus; Monroy, Igancio Alberto; Monteil, Stephane; Morandin, Mauro; Morello, Michael Joseph; Morgunova, Olga; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Mulder, Mick; Müller, Dominik; Müller, Janine; Müller, Katharina; Müller, Vanessa; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nandi, Anita; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Thi Dung; Nguyen-Mau, Chung; Nieswand, Simon; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Nogay, Alla; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Ogilvy, Stephen; Oldeman, Rudolf; Onderwater, Gerco; Ossowska, Anna; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Aranzazu; Pais, Preema Rennee; Palano, Antimo; Palutan, Matteo; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parker, William; Parkes, Christopher; Passaleva, Giovanni; Pastore, Alessandra; Patel, Mitesh; Patrignani, Claudia; Pearce, Alex; Pellegrino, Antonio; Penso, Gianni; Pepe Altarelli, Monica; Perazzini, Stefano; Perret, Pascal; Pescatore, Luca; Petridis, Konstantinos; Petrolini, Alessandro; Petrov, Aleksandr; Petruzzo, Marco; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pikies, Malgorzata; Pinci, Davide; Pistone, Alessandro; Piucci, Alessio; Placinta, Vlad-Mihai; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poli Lener, Marco; Poluektov, Anton; Polyakov, Ivan; Polycarpo, Erica; Pomery, Gabriela Johanna; Ponce, Sebastien; Popov, Alexander; Popov, Dmitry; Poslavskii, Stanislav; Potterat, Cédric; Price, Eugenia; Prisciandaro, Jessica; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Pullen, Hannah Louise; Punzi, Giovanni; Qian, Wenbin; Quagliani, Renato; Quintana, Boris; Rachwal, Bartlomiej; Rademacker, Jonas; Rama, Matteo; Ramos Pernas, Miguel; Rangel, Murilo; Raniuk, Iurii; Ratnikov, Fedor; Raven, Gerhard; Ravonel Salzgeber, Melody; Reboud, Meril; Redi, Federico; Reichert, Stefanie; dos Reis, Alberto; Remon Alepuz, Clara; Renaudin, Victor; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vicente; Robbe, Patrick; Robert, Arnaud; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Lopez, Jairo Alexis; Rodriguez Perez, Pablo; Rogozhnikov, Alexey; Roiser, Stefan; Rollings, Alexandra Paige; Romanovskiy, Vladimir; Romero Vidal, Antonio; Ronayne, John William; Rotondo, Marcello; Rudolph, Matthew Scott; Ruf, Thomas; Ruiz Valls, Pablo; Ruiz Vidal, Joan; Saborido Silva, Juan Jose; Sadykhov, Elnur; Sagidova, Naylya; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santimaria, Marco; Santovetti, Emanuele; Sarpis, Gediminas; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrina, Darya; Schael, Stefan; Schellenberg, Margarete; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmelzer, Timon; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schreiner, HF; Schubert, Konstantin; Schubiger, Maxime; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Semennikov, Alexander; Sepulveda, Eduardo Enrique; Sergi, Antonino; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Siddi, Benedetto Gianluca; Silva Coutinho, Rafael; Silva de Oliveira, Luiz Gustavo; Simi, Gabriele; Simone, Saverio; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Eluned; Smith, Iwan Thomas; Smith, Jackson; Smith, Mark; Soares Lavra, Lais; Sokoloff, Michael; Soler, Paul; Souza De Paula, Bruno; Spaan, Bernhard; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Stefko, Pavol; Stefkova, Slavomira; Steinkamp, Olaf; Stemmle, Simon; Stenyakin, Oleg; Stepanova, Margarita; Stevens, Holger; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Stramaglia, Maria Elena; Straticiuc, Mihai; Straumann, Ulrich; Sun, Jiayin; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Syropoulos, Vasileios; Szczekowski, Marek; Szumlak, Tomasz; Szymanski, Maciej Pawel; T'Jampens, Stephane; Tayduganov, Andrey; Tekampe, Tobias; Tellarini, Giulia; Teubert, Frederic; Thomas, Eric; van Tilburg, Jeroen; Tilley, Matthew James; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Toriello, Francis; Tourinho Jadallah Aoude, Rafael; Tournefier, Edwige; Traill, Murdo; Tran, Minh Tâm; Tresch, Marco; Trisovic, Ana; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tully, Alison; Tuning, Niels; Ukleja, Artur; Usachov, Andrii; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagner, Alexander; Vagnoni, Vincenzo; Valassi, Andrea; Valat, Sebastien; Valenti, Giovanni; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vecchi, Stefania; van Veghel, Maarten; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Venkateswaran, Aravindhan; Verlage, Tobias Anton; Vernet, Maxime; Vesterinen, Mika; Viana Barbosa, Joao Vitor; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Viemann, Harald; Vilasis-Cardona, Xavier; Vitti, Marcela; Volkov, Vladimir; Vollhardt, Achim; Voneki, Balazs; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; de Vries, Jacco; Vázquez Sierra, Carlos; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wang, Jianchun; Ward, David; Wark, Heather Mckenzie; Watson, Nigel; Websdale, David; Weiden, Andreas; Whitehead, Mark; Wicht, Jean; Wilkinson, Guy; Wilkinson, Michael; Williams, Mark Richard James; Williams, Matthew; Williams, Mike; Williams, Timothy; Wilson, Fergus; Wimberley, Jack; Winn, Michael Andreas; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wraight, Kenneth; Wyllie, Kenneth; Xie, Yuehong; Xu, Zhirui; Yang, Zhenwei; Yang, Zishuo; Yao, Yuezhe; Yin, Hang; Yu, Jiesheng; Yuan, Xuhao; Yushchenko, Oleg; Zarebski, Kristian Alexander; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Yanxi; Zhelezov, Alexey; Zheng, Yangheng; Zhu, Xianglei; Zhukov, Valery; Zonneveld, Jennifer Brigitta; Zucchelli, Stefano

2017-11-03

A search for baryon-number-violating $\\Xi_b^0$ oscillations is performed with a sample of $pp$ collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 3 fb$^{-1}$. The baryon number at the moment of production is identified by requiring that the $\\Xi_b^0$ come from the decay of a resonance $\\Xi_b^{*-} \\to \\Xi_b^0 \\pi^-$ or $\\Xi_b^{\\prime-} \\to \\Xi_b^0 \\pi^-$, and the baryon number at the moment of decay is identified from the final state using the decays $\\Xi_b^0 \\to \\Xi_c^+ \\pi^-, ~ \\Xi_c^+ \\to p K^- \\pi^+$. No evidence of baryon number violation is found, and an upper limit is set on the oscillation rate of $\\omega < 0.08$ ps$^{-1}$, where $\\omega$ is the associated angular frequency.

Baryon number fluctuations and the phase structure in the PNJL model

Energy Technology Data Exchange (ETDEWEB)

Shao, Guo-yun; Tang, Zhan-duo; Gao, Xue-yan; He, Wei-bo [Xi' an Jiaotong University, School of Science, Xi' an, Shaanxi (China)

2018-02-15

We investigate the kurtosis and skewness of net-baryon number fluctuations in the Polyakov loop extended Nambu-Jona-Lasinio (PNJL) model, and discuss the relations between fluctuation distributions and the phase structure of quark-gluon matter. The calculation shows that the traces of chiral and deconfinement transitions can be effectively reflected by the kurtosis and skewness of net-baryon number fluctuations not only in the critical region but also in the crossover region. The contour plot of baryon number kurtosis derived in the PNJL model can qualitatively explain the behavior of net-proton number kurtosis in the STAR beam energy scan experiments. Moreover, the three-dimensional presentations of the kurtosis and skewness in this study are helpful to understand the relations between baryon number fluctuations and QCD phase structure. (orig.)

Observation of the (Omega)b- Baryon and Measurement of the Properties of the Ξb- and (Omega)b- Baryons

International Nuclear Information System (INIS)

Aaltonen, T.; Adelman, Jahred A.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, Dante E.; Anastassov, A.; Annovi, Alberto; Antos, Jaroslav; Apollinari, G.; Apresyan, A.

2009-01-01

The authors report the observation of the bottom, doubly-strange baryon (Omega) b - through the decay chain (Omega) b - → J/ψ(Omega) - , where J/ψ → μ + μ - , (Omega) - → ΛK - , and Λ → p π - , using 4.2 fb -1 of data from p(bar p) collisions at √s = 1.96 TeV, and recorded with the Collider Detector at Fermilab. A signal is observed whose probability of arising from a background fluctuation is 4.0 x 10 -8 , or 5.5 Gaussian standard deviations. The (Omega) b - mass is measured to be 6054.4 ± 6.8(stat.) ± 0.9(syst.) MeV/c 2 . The lifetime of the (Omega) b - baryon is measured to be 1.13 -0.40 +0.53 (stat.) ± 0.02(syst.) ps. In addition, for the Ξ b - baryon they measure a mass of 5790.9 ± 2.6(stat.) ± 0.8(syst.) MeV/c 2 and a lifetime of 1.56 -0.25 +0.27 (stat.) ± 0.02(syst.) ps.

Baryon spectroscopy and SU(6)

International Nuclear Information System (INIS)

Litchfield, P.

1977-09-01

An elementary account of the SU(6) formalism for baryons is given. The assignment of the known resonances to SU(6) multiplets is discussed and an experimental scheme given for the spectrum of SU(6) x 0(2) multiplets. (author)

Study of a possible S=+1 dynamically generated baryonic resonance

International Nuclear Information System (INIS)

Sarkar, S.; Oset, E.; Vaca, M.J.V.

2005-01-01

Starting from the lowest-order chiral Lagrangian for the interaction of the baryon decuplet with the octet of pseudoscalar mesons we find an attractive interaction in the ΔK channel with L=0 and I=1, while the interaction is repulsive for I=2. The attractive interaction leads to a pole in the second Riemann sheet of the complex plane and manifests itself in a large strength of the K scattering amplitude close to the ΔK threshold, which is not the case for I=2. However, we also make a study of uncertainties in the model and conclude that the existence of this pole depends sensitively upon the input used and can disappear within reasonable variations of the input parameters. We take advantage to study the stability of the other poles obtained for the 3/2 - dynamically generated resonances of the model and conclude that they are stable and not contingent to reasonable changes in the input of the theory

Diquark structure in heavy quark baryons in a geometric model

International Nuclear Information System (INIS)

Paria, Lina; Abbas, Afsar

1996-01-01

Using a geometric model to study the structure of hadrons, baryons having one, two and three heavy quarks have been studied here. The study reveals diquark structure in baryons with one and two heavy quarks but not with three heavy identical quarks. (author). 15 refs., 2 figs., 2 tabs

Deep inelastic lepton-nucleus scattering from the light-cone quantum field theory

International Nuclear Information System (INIS)

Boqiang Ma; Ji Sun

1990-01-01

We show that for deep inelastic lepton-nucleus scattering, the conditions which validate the impulse approximation are hardly satisfied when using ordinary instant form dynamics in the rest frame of the nucleus, whereas they are well satisfied when using instant form dynamics in the infinite-momentum frame, or using light-front form dynamics in an ordinary frame. Therefore a reliable theoretical treatment of deep inelastic lepton-nucleus scattering should be performed in the time-ordered perturbation theory in the infinite-momentum frame, or its equivalent, the light-cone perturbation theory in an ordinary frame. To this end, we extend the light-cone quantum field theory to the baryon-meson field to establish a relativistic composite model of nuclei. We then apply the impulse approximation to deep inelastic lepton-nucleus scattering in this model.(author)

On the phase strucutre of baryonic matter

International Nuclear Information System (INIS)

Heide, E.; Ellis, P.J.

1991-01-01

We have studied the phase structure of baryonic matter in a model which includes nucleons and delta resonances interacting with σ- and ω-mesons. In the mean-field approximation, the existence of phase transitions to delta matter and to a baryon-antibaryon plasma was strongly dependent on the values chosen for the equilibrium effective mass and compression modulus. When vacuum fluctuations were included, the physically acceptable solutions only yielded a liquid-gas phase transition. Further, these solutions were restricted to rather large values of the effective mass and compression modulus which did not include the currently accepted values. (orig.)

What can we learn from unpolarized and polarized electroproduction of fast baryons?

International Nuclear Information System (INIS)

Artru, X.; Mekhfi, M.

1991-01-01

Two applications of semi-inclusive electroproduction of fast baryons are presented: (i) The steepness of the baryon spectrum at medium rapidity can give information about the general mechanisms of baryon production in soft and hard processes. (ii) With a polarized target and a detector which analyses the polarization of final Λ's, the aptitude of quarks to carry transverse polarization can be tested for the first time. (orig.)

Baryon superfluidity and neutrino emissivity of neutron stars

International Nuclear Information System (INIS)

Takatsuka, Tatsuyuki; Tamagaki, Ryozo

2004-01-01

For neutron stars with hyperon-mixed cores, neutrino emissivity is studied using the properties of neutron star matter determined under the equation of state, which is obtained by introducing a repulsive three-body force universal for all the baryons so as to assure the maximum mass of neutron stars compatible with observations. The case without a meson condensate is treated. We choose the inputs provided by nuclear physics, with a reliable allowance. Paying attention to the density dependence of the critical temperatures of the baryon superfluids, which reflect the nature of the baryon-baryon interaction and control neutron star cooling, we show what neutrino emission processes are efficient in regions both with and without hyperon mixing. By comparing the calculated emissivities with respect to densities, we can conclude that at densities lower than about 4 times the nuclear density, the Cooper-pair process arising from the neutron 3 P 2 superfluid dominates, while at higher densities the hyperon direct Urca process dominates. For the hyperon direct Urca process to be a candidate responsible for rapid cooling compatible with observations, a moderately large energy gap of the Λ-particle 1 S 0 superfluid is required to suppress its large emissivity. The implications of these results are discussed in the relation to thermal evolution of neutron stars. (author)

An investigation of triply heavy baryon production at hadron colliders

Energy Technology Data Exchange (ETDEWEB)

Gomshi Nobary, M.A. [Department of Physics, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of) and Center for Theoretical Physics and Mathematics, AEOI, Roosbeh Building, PO Box 11365-8486, Tehran (Iran, Islamic Republic of)]. E-mail: mnobary@razi.ac.ir; Sepahvand, R. [Department of Physics, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of)

2006-05-01

The triply heavy baryons have a rather diverse mass range. While some of them possess considerable production rates at existing facilities, others need to be produced at future high energy colliders. Here we study the direct fragmentation production of the {omega}{sub ccc} and {omega}{sub bbb} baryons as the prototypes of triply heavy baryons at the hadron colliders with different s. We present and compare the transverse momentum distributions of the differential cross sections, p{sub T}{sup min} distributions of total cross sections and the integrated total cross sections of these states at the RHIC, the Tevatron Run II and the CERN LHC.

Problems in baryon spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Capstick, S. [Florida State Univ., Tallahassee, FL (United States)

1994-04-01

Current issues and problems in the physics of ground- and excited-state baryons are considered, and are classified into those which should be resolved by CEBAF in its present form, and those which may require CEBAF to undergo an energy upgrade to 8 GeV or more. Recent theoretical developments designed to address these problems are outlined.

Diquarks in rotating baryons

International Nuclear Information System (INIS)

Martin, A.

1989-01-01

This paper shows that the minimum energy three-quark classical configuration for a given angular momentum and linear two-body potentials between the quarks is a quark-diquark system. The authors deduce from this that baryons at large angular momentum have a quark-diquark structure. Explicit calculations by Flack, Richard and Silvestre-Brac show this effect

Experimental study of charmed baryons at SuperLEAR

International Nuclear Information System (INIS)

Poulet, M.

1991-01-01

The possibility to study and detect the charmed baryons at SuperLEAR was examined. It was found that it is possible only if the search is restricted to the single charm baryons Λ c , Σ c , Ξ c . The experimental approach requires high luminosity and some complexity of the detection system. It has to be considered as a second generation jet target experiment in a range of p-bar momentum from 8 to 15 GeV/c. (R.P.) 12 refs., 2 figs

On finite volume effects in the chiral extrapolation of baryon masses

CERN Document Server

Lutz, M F M; Kobdaj, C; Schwarz, K

2014-01-01

We perform an analysis of the QCD lattice data on the baryon octet and decuplet masses based on the relativistic chiral Lagrangian. The baryon self energies are computed in a finite volume at next-to-next-to-next-to leading order (N^3LO), where the dependence on the physical meson and baryon masses is kept. The number of free parameters is reduced significantly down to 12 by relying on large-N_c sum rules. Altogether we describe accurately more than 220 data points from six different lattice groups, BMW, PACS-CS, HSC, LHPC, QCDSF-UKQCD and NPLQCD. Precise values for all counter terms relevant at N^3LO are predicted. In particular we extract a pion-nucleon sigma term of (39 +- 1) MeV and a strangeness sigma term of the nucleon of sigma_{sN} simeq (4 +- 1) MeV. The flavour SU(3) chiral limit of the baryon octet and decuplet masses is determined with ( 802 +- 4 ) MeV and (1103 +- 6) MeV. Detailed predictions for the baryon masses as currently evaluated by the ETM lattice QCD group are made.

Polarization in pp → p(baryon)

International Nuclear Information System (INIS)

Castillo-Vallejo, Victor M.; Felix, Julian

2003-01-01

It's introduced a calculation, which is based on symmetries followed by high energy hadronic interactions, of resonance polarization and specific angular momentum state polarization created in pp → p(baryon)

The search for exotic baryons at the HERMES experiment

Energy Technology Data Exchange (ETDEWEB)

Deconinck, Wouter

2008-07-15

One of the interesting questions of Quantum Chromodynamics, the theory that governs the interactions between quarks and gluons, has been whether it is possible to observe hadrons which can not be explained as a combination of only two or three valence quarks. In numerous searches the existence of these exotic hadrons could not be confirmed. Recently, calculations based on the quark soliton model predicted the narrow exotic baryons {theta}{sup +} and {xi}{sup --}. A narrow resonance identified as the {theta}{sup +} was observed by several experiments at the predicted mass of 1540 MeV, but later followed by several dedicated experiments that could not confirm these positive results. At the HERMES experiment a search for the quasi-real photoproduction of the exotic baryon {theta}{sup +} on a deuterium target and the subsequent decay through pK{sup 0}{sub S} {yields} p{pi}{sup +}{pi}{sup -} revealed a narrow resonance in the pK{sup 0}{sub S} invariant mass distribution at 1528 MeV. In the search for the corresponding antiparticle {xi}{sup --} the result is consistent with zero events. In this thesis we present the search for the exotic baryon {xi}{sup --} on a deuterium target in the data sample used for the observation of the {theta}{sup +}. An upper limit on the cross section of the exotic baryon {xi}{sup --} is determined. The search for the exotic baryon {theta}{sup +} on hydrogen and deuterium targets at the HERMES experiment is extensively discussed. The event mixing method can be used to estimate the distribution of background events. Several difficulties with this method were addressed, but the background description in the case of the exotic baryon {theta}{sup +} remains unconvincing. Between the years 2002 and 2005 the HERMES experiment operated with a magnetic holding field around the hydrogen target. A method for the reconstruction of displaced vertices in this field was developed. The data collected during the years 2006 and 2007 offer an integrated

Conformal Symmetry Patterns in Baryon Spectra

International Nuclear Information System (INIS)

Kirchbach, Mariana; Compean, Cliffor B

2011-01-01

Attention is drawn to the fact that the spectra of the baryons of the lightest flavors, the nucleon and the Δ, carry quantum numbers characteristic for an unitary representation of the conformal group. We show that the above phenomenon is well explained for baryons whose internal structure is dominated by a quark-diquark configuration that resides in a conformally compactified Minkowski space time, R 1 x S 3 , and is described by means of the conformal scale equation there. The R 1 x S 3 space-time represents the boundary of the conformally compactified AdS 5 , on which one expects to encounter a conformal theory in accord with the gauge-gravity duality. Within this context, our model is congruent with AdS 5 /CFT 4 .

Kinematic Sunyaev-Zel'dovich Effect with Projected Fields: A Novel Probe of the Baryon Distribution with Planck, WMAP, and WISE Data.

Science.gov (United States)

Hill, J Colin; Ferraro, Simone; Battaglia, Nick; Liu, Jia; Spergel, David N

2016-07-29

The kinematic Sunyaev-Zel'dovich (KSZ) effect-the Doppler boosting of cosmic microwave background (CMB) photons due to Compton scattering off free electrons with nonzero bulk velocity-probes the abundance and the distribution of baryons in the Universe. All KSZ measurements to date have explicitly required spectroscopic redshifts. Here, we implement a novel estimator for the KSZ-large-scale structure cross-correlation based on projected fields: it does not require redshift estimates for individual objects, allowing KSZ measurements from large-scale imaging surveys. We apply this estimator to cleaned CMB temperature maps constructed from Planck and WMAP data and a galaxy sample from the Wide-field Infrared Survey Explorer (WISE). We measure the KSZ effect at 3.8σ-4.5σ significance, depending on the use of additional WISE galaxy bias constraints. We verify that our measurements are robust to possible dust emission from the WISE galaxies. Assuming the standard Λ cold dark matter cosmology, we directly constrain (f_{b}/0.158)(f_{free}/1.0)=1.48±0.19 (statistical error only) at redshift z≈0.4, where f_{b} is the fraction of matter in baryonic form and f_{free} is the free electron fraction. This is the tightest KSZ-derived constraint reported to date on these parameters. Astronomers have long known that baryons do not trace dark matter on ∼ kiloparsec scales and there has been strong evidence that galaxies are baryon poor. The consistency between the f_{b} value found here and the values inferred from analyses of the primordial CMB and big bang nucleosynthesis verifies that baryons approximately trace the dark matter distribution down to ∼ megaparsec scales. While our projected-field estimator is already competitive with other KSZ approaches when applied to current data sets (because we are able to use the full-sky WISE photometric survey), it will yield enormous signal-to-noise ratios when applied to upcoming high-resolution, multifrequency CMB surveys.

Mesonic and baryonic Regge trajectories with quantized masses

International Nuclear Information System (INIS)

Hothi, N.; Bisht, S.

2011-01-01

We have constructed some Regge trajectories for mesons and baryons by taking the 70 MeV spinless mass quanta as the ultimate building block for the light hadrons. In order to make masses integral multiples of seventy, small changes in masses has been made with due explanation. We have shown how a linear relationship between J and M 2 is maintained by considering quantized hadron masses, which is a direct consequence of the string model and gives a strong clue for quark confinement. It has also been established that mesons and baryons have different slopes and the slopes of baryons is less than the slope of the mesons. This clearly defies the concept of universality of slopes (α ≅ 1.1 GeV 2 ) of hadrons, which can only be achieved if the strings joining the quarks have constant string tension α 1/(2πω) (where ω is the string tension). (author)

Spin effects and the production of heavy baryons in $Z^{0}$ boson decays

CERN Document Server

Saleev, V A

1999-01-01

Predictions are made within the scope of perturbative quantum chromodynamics and the nonrelativistic two-quark baryon model of the magnitude and dependence upon z (the fraction of the momentum of the heavy quark carried off by the baryon) of the longitudinal spin asymmetry parameter A/sub RL/ in the direct creation of Lambda /sub b / and Lambda /sub c/ baryons in the Z/sup 0/-boson channel in the LEP e/sup +/e/sup -/ collider. An estimate is found for the value of A /sub RL/( Lambda /sub b/) in the cascade production of Lambda /sub b/ baryons. (27 refs).

Meson-baryon four-body reaction amplitudes in exact SU(4)

International Nuclear Information System (INIS)

Liede, I.; Maalampi, J.; Roos, M.

1976-01-01

Fully SU(4) symmetric meson-baryon four body reaction amplitudes are presented in terms of SU(4) eigenamplitudes. The mesons and baryons considered belong to the SU(4) representations 15 and 20, respectively. Using these reletions, the cross-sections for the production of charmed particles can be predicted from known uncharmed reactions. (author)

Elastic I=3 /2 p -wave nucleon-pion scattering amplitude and the Δ (1232) resonance from Nf=2+1 lattice QCD

DEFF Research Database (Denmark)

Andersen, Christian Walther; Bulava, John; Hörz, Ben

2018-01-01

We present the first direct determination of meson-baryon resonance parameters from a scattering amplitude calculated using lattice QCD. In particular, we calculate the elastic I=3/2, p-wave nucleon-pion amplitude on a single ensemble of Nf=2+1 Wilson-clover fermions with mπ=280 MeV and mK=460 Me......V. At these quark masses, the Δ(1232) resonance pole is found close to the N-π threshold and a Breit-Wigner fit to the amplitude gives gΔNπBW=19.0(4.7) in agreement with phenomenological determinations.......We present the first direct determination of meson-baryon resonance parameters from a scattering amplitude calculated using lattice QCD. In particular, we calculate the elastic I=3/2, p-wave nucleon-pion amplitude on a single ensemble of Nf=2+1 Wilson-clover fermions with mπ=280 MeV and mK=460 Me...

Determination of the quark coupling strength $|V_{ub}|$ using baryonic decays

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00392760

This thesis presents the first determination of $|V_{ub}|$ at a hadron collider and in a baryonic decay. The determination is made by measuring the ratio of branching fractions of the baryonic decays $\\Lambda^0_b \\to p \\mu^-\\overline{\

Resonance families and local duality relations in the meson-baryon scattering

International Nuclear Information System (INIS)

Ino, Taketoshi

1989-01-01

The local duality relations proposed previously are applied systematically to the P 8 -B 8 scattering, where P 8 and B 8 denote the 0 - unitary octet and 1/2 + one, respectively. The system of the relations involves the harmonic-oscillator spectrum of SU(6) x O(3) L multiplets, and for a process with one exotic channel (the exotic u-channel), the relation relates the s-channel resonance family N s with the t-channel one N t in terms of residues of the scattering amplitude at s-and t-channel resonances a and b (a is an element of N s , b is an element of N t ) in the narrow-width approximation. The resonance family N s (N t ) is defined to be a set of s-(t-) channel resonances with a fixed total number N s (N t ) of quanta of harmonic-oscillator excitations. The system of the relations is powerful in predicting mass ratios and coupling ratios for resonances. It is found that predictions are consistent with available experiments. Some discussion is made on the present results and previous successes in a work where we obtained a uniquely determined π - π + →π - π + dual Born amplitude, starting with the most general Veneziano-type amplitude and restricting parameters in it by the system of the relations and an asymptotic convergence condition. (author)

Left-cut contribution to the dispersion relation for the elastic electron - atomic-hydrogen scattering amplitude

International Nuclear Information System (INIS)

Amusia, M.Ya.; Kuchiev, M.Yu.

1979-01-01

The jump in the electron - atomic-hydrogen forward scattering amplitude at the cut extending to the left from E = -0.5 au is calculated as a function of the incident electron energy, E, by using the second Born approximation. The contribution from this singularity to the dispersion relation is determined. (Auth.)

Beauty baryons: Recent CDF results

International Nuclear Information System (INIS)

Tseng, J.

1996-12-01

Using data collected between 1992 and 1995 at the Fermilab Tevatron, CDF has searched for the Λ b baryon through both semileptonic and hadronic decay channels. This presentation reviews measurements of the Λ b mass, lifetime, and production and decay rates performed with this data

Baryon symmetric big-bang cosmology. [matter-antimatter symmetry

Science.gov (United States)

Stecker, F. W.

1978-01-01

The framework of baryon-symmetric big-bang cosmology offers the greatest potential for deducing the evolution of the universe as a consequence of physical laws and processes with the minimum number of arbitrary assumptions as to initial conditions in the big-bang. In addition, it offers the possibility of explaining the photon-baryon ratio in the universe and how galaxies and galaxy clusters are formed, and also provides the only acceptable explanation at present for the origin of the cosmic gamma ray background radiation.

Baryon - antibaryon asymmetry in central rapidity region at LHC ALICE

International Nuclear Information System (INIS)

Broz, M.

2008-01-01

Study of asymmetry in number of baryons and antibaryons in central rapidity region is important for clarification of baryon number carriers character. Effect we are interested in is small, can be hidden by systematical processes of particle track reconstruction and identification. To make corrections on these effects is the aim of this thesis. (author)

Measurement of beauty baryons production and lifetime in Z0 hadronic decays

International Nuclear Information System (INIS)

Bianchi, F.

1994-01-01

A study of the production of beauty baryons in Z 0 decays is reported. The analysis is based on 1 Million Z 0 hadronic events collected by the DELPHI detector in the 1990-92 data taking. Beauty baryon signals are obtained with three complementary methods: search of Λ (Λ-bar) correlated to a high p T l - (l + ) in the same jet; the presence of a secondary vertex formed by a fast proton (p>5 GeV/c) and a lepton of opposite sign; the presence of Λ c baryon associated with a high p T lepton in the same jet. From these signals, the average lifetime of beauty baryons and inclusive branching fractions have been measured. (author). 5 refs., 4 figs

Measurement of the {Lambda}{sub c} charmed baryon production and the study of the {Lambda}{sub c} baryon semi-leptonic decays by the DELPHI experiment at LEP; Mesure de la production du baryon charme {Lambda}{sub c} et etude des desintegrations semi-leptoniques de baryon {Lambda}{sub c} par l`experience DELPHI au LEP

Energy Technology Data Exchange (ETDEWEB)

Bertini, D [Lyon-1 Univ., 69 (France)

1997-04-24

By using the data accumulated in the DELPHI experiment from 1992 to 1994 we present the results of the production rate measurement of {Lambda}{sub c} charmed baryons generated in the bb-bar and cc-bar events. For these measurements we reconstructed entirely the {Lambda}{sub c} baryons decaying in pK{pi}. Then we select a set of bottom baryons {Lambda}{sub b}{sup 0} by means of its semi-leptonic decays in {Lambda}{sub c}{sup +}l{sup -}{nu}{sub l}-bar. The study of distribution of these events as a function of the transfer momentum allowed estimating for the first time the slope of the {Lambda}{sub b}{sup 0} form factor. (author) 93 refs.

Spectroscopy of doubly and triply-charmed baryons from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Padmanath, M. [Tata Institute; Edwards, Robert G. [JLAB; Mathur, Nilmani [Tata Institute; Peardon, Michael [Trinity College, Dublin

2013-11-01

We present the ground and excited state spectra of doubly and triply-charmed baryons by using lattice QCD with dynamical clover fermions. A large set of baryonic operators that respect the symmetries of the lattice and are obtained after subduction from their continuum analogues are utilized. Using novel computational techniques correlation functions of these operators are generated and the variational method is exploited to extract excited states. The lattice spectra that we obtain have baryonic states with well-defined total spins up to 7/2 and the low lying states remarkably resemble the expectations of quantum numbers from SU(6) Ⓧ O(3) symmetry. Various energy splittings between the extracted states, including splittings due to hyperfine as well as spin-orbit coupling, are considered and those are also compared against similar energy splittings at other quark masses. Using those splittings for doubly-charmed baryons, and taking input of experimental Bc meson mass, we predict the mass splittings of B*c-Bc to be about 80 ± 8 MeV and mΩccb=8050±10 MeV.

The quark combination mechanism and the production percentages of excited baryons

International Nuclear Information System (INIS)

Wang Qun; Xie Qubing

1994-01-01

The authors derives a set of basic relations about octet, decuplet and Singlet baryon production weights under two principles in multiparticle production. From these relations, the give the origin of 'spin suppression' phenomenon, and successfully explain why the singlet baryons have high multiplicities

Primary and scattering contributions to beta scaled dose point kernels by means of Monte Carlo simulations

International Nuclear Information System (INIS)

Valente, Mauro; Botta, Francesca; Pedroli, Guido

2012-01-01

Beta-emitters have proved to be appropriate for radioimmunotherapy. The dosimetric characterization of each radionuclide has to be carefully investigated. One usual and practical dosimetric approach is the calculation of dose distribution from a unit point source emitting particles according to any radionuclide of interest, which is known as dose point kernel. Absorbed dose distributions are due to primary and radiation scattering contributions. This work presented a method capable of performing dose distributions for nuclear medicine dosimetry by means of Monte Carlo methods. Dedicated subroutines have been developed in order to separately compute primary and scattering contributions to the total absorbed dose, performing particle transport up to 1 keV or least. Preliminarily, the suitability of the calculation method has been satisfactory, being tested for monoenergetic sources, and it was further applied to the characterization of different beta-minus radionuclides of nuclear medicine interests for radioimmunotherapy. (author)

Compression of dark halos by baryon infall - Self-similar solutions

International Nuclear Information System (INIS)

Ryden, B.S.

1991-01-01

The compression of dissipationless halos by dissipative baryon infall is examined through the use of self-similar models. The models are spherically symmetric, with asymptotic density profiles of given form. A fraction f of the matter consists of freely falling baryons; the remainder of the matter, consisting of dark matter with initial dispersion anisotropy beta is gravitationally compressed by the infalling baryons. Analytic results are presented in the limiting cases f = 1 and f = 0. Numerical results are given for halos with varying values of alpha, beta, and f. The compression of the dark matter is found to be adiabatic and has a Mach number less than 1 throughout the halo. 10 refs

Comments on 'The OZI rule does not apply to baryons'

International Nuclear Information System (INIS)

Lindenbaum, S.J.; Longacre, R.S.

1990-01-01

We demonstrate that the arguments made by Ellis, Gabathuler and Karliner that meson-baryon couplings could evade the OZI rule are irrelevant to the arguments we have made before. This is so since even if we assume that meson-baryon couplings can violate OZI, we clearly demonstrate that the coupling involved in our π - p→φφn is ππ→φφ which does not involve meson-baryon couplings. Thus our arguments that the g T (2010), g T' (2300) and g T'' (2340) are naturally explained in the context of QCD by the hypothesis that one to three glueballs are produced in the intermediate state are not affected by arguments made by Ellis et al. (orig.)

Quasi-elastic production of charmed baryons in neutrino-nUcleon interactions

International Nuclear Information System (INIS)

Zhizhin, E.D.; Nikitin, Yu.P.; Fanchenko, M.S.

1983-01-01

Quasielastic production of charmed baryons Λsub(c)sup(+), Σsub(c)sup(+), and Σsub(c)sup(++) in neutrino reactions on nucleons is studied. Differential and total cross sections are calculated for two sets of the parameters Msub(V), Msub(A) which determine the form factors of weak transitions of nucleons into charmed baryons. The chosen parameter values allow to obtain the cross sections which overlap the entire uncertainty range of theoretical predictions. The authors pay attention to an important kinematical effect that for monochromatic neutrino beams the values of the charmed baryon emission angles are limited (THETA < THETAsub(max)) and the differential cross section dσ/dΩ strongly increases in the vicinity of the angles THETA=THETAsub(max). Possibilities in experimental studying of the above processes and in extracting unique information on the structure of charmed baryons from experimental data are

Picture book of nucleon--nucleon scattering: amplitudes, models, double- and triple-spin observables

International Nuclear Information System (INIS)

Field, R.D.; Stevens, P.R.

1975-01-01

A comprehensive study of nucleon-nucleon scattering is presented with particular emphasis on the underlying amplitude structure. The five complex NN amplitudes are determined as a function of energy and momentum transfer from existing pp, anti pp, and np elastic scattering data and np and anti pp CHEX data. Some constraints determined from meson-baryon fits are imposed. The resulting amplitudes are used to make predictions of forthcoming double- and triple-spin measurements, and are also compared with the model amplitudes of Kane and Seidl. In addition, the usefulness of transversity amplitudes in NN scattering is discussed, the status of our present knowledge concerning them is examined, and model predictions of these amplitudes are displayed. The paper is presented in a ''picture book'' form so that the reader can get a good overview of NN scattering by studying the figures and reading the tables and figure captions

Current algebra, baryons and quark confinement

International Nuclear Information System (INIS)

Witten, E.

1983-01-01

It is shown that ordinary baryons can be understood as solitons in current algebra effective lagrangiangs. The formation of color flux tubes can also be seen in current algebra, under certain conditions. (orig.)

Baryon-antibaryon flavor correlations in e+e- annihilation

International Nuclear Information System (INIS)

Liang Zuo-tang; Xie Qu-bing

1991-01-01

Under the assumption that in e + e - annihilations baryons and antibaryons are produced by the stochastic combination of quarks and antiquarks, the baryon-antibaryon flavor correlations come completely from the global compensation of the flavors of all of the quarks and antiquarks. This can at least provide us with a lower limit for the baryon-antibaryon flavor correlations in various models, and by comparing them with experiment, we can see if and to what extent one has the necessity or freedom to introduce any other mechanism to produce extra baryon-antibaryon flavor correlations. Starting from this assumption, we have made calculations on left-angle n Λbar Λ right-angle/left-angle n Λ right-angle, left-angle n Ξ - bar Λ right-angle/left-angle n Ξ - right-angle, and left-angle n Λ(1520)bar Λ right-angle/left-angle n Λ(1520) right-angle, which have already been measured, and on similar quantities such as left-angle n Σ ± bar Λ right-angle left-angle n Σ ± right-angle, left-angle n Σ *± bar Λ right-angle/left-angle n Σ *± right-angle,left-angle n Ξ *- bar Λ right-angle left-angle n Ξ *- right-angle, and left-angle n Ω - bar Λ right-angle/left-angle n Ω - right-angle, which have not been measured yet. Comparing with the available data, it seems that there is little room left for other mechanisms which result in extra flavor correlations

Baryon observables and color confinement

International Nuclear Information System (INIS)

Jackson, A.D.

1987-01-01

Calculations of baryon observables within the framework of the chiral bag model are reviewed. The results of such calculations are found to be remarkably insensitive to the radius of color confinement and indicate the difficulty of finding unambiguous evidence for quarks in nuclei. 13 refs.; 5 figs

Relativistic kinetics of baryon production in hot Universe

International Nuclear Information System (INIS)

Ignat'ev, Yu.G.

1985-01-01

The process of baryon production in the hot Universe is investigated in the framework of the relativistic kinetic theory. The exact solution of kinetic equations for supermassive bosons is obtained, thus giving the possibility to correct the results of previous papers: the known optimum domain of baryon production m sub(X) > α sub(X)msub(PI)√N js complemented by the small-mass boson domain, m sub(X) << α sub(X) m sub(PI)√N; as a result, the cosmological lower-limit restriction on the superheavy bosons masses js removed

Contribution to Λ+c → φΣ, φΛ and p anti Ko from excited states

International Nuclear Information System (INIS)

Turan, G.; Eeg, J.O.

1990-12-01

Contributions to Λ c + → φΣ, φΛ and p anti K o from excited states are considered. The calculations are performed within the MIT-bag model and a Heavy Quark bag model. Because the mass of Λ c + is rather big compared to the strange baryons, excited baryon states with mass close to that of Λ c + in some cases give significant pole contributions to the decay amplitudes of Λ c + . 20 refs., 3 tabs

How sensitive are di-leptons from ρ mesons to the high baryon density region?

International Nuclear Information System (INIS)

Vogel, S.; Schmidt, K.; Santini, E.; Sturm, C.; Bleicher, M.; Petersen, H.; Aichelin, J.

2008-01-01

We show that the measurement of dileptons might provide only a restricted view into the most dense stages of heavy-ion reactions. Thus, possible studies of meson and baryon properties at high baryon densities, as, e.g., done at the GSI High Acceptance DiElectron Spectrometer (HADES) and envisioned for the Facility for Antiproton and Ion Research (FAIR) compressed baryonic matter experiments, might observe weaker effects than currently expected in certain approaches. We argue that the strong absorption of resonances in the high-baryon-density region of the heavy-ion collision masks information from the early hot and dense phase due to a strong increase of the total decay width because of collisional broadening. To obtain additional information, we also compare the currently used approaches to extract dileptons from transport simulations, i.e., shining, only vector mesons from final baryon resonance decays and instant emission of dileptons and find a strong sensitivity on the method employed in particular at FAIR and the CERN Super Proton Synchrotron energies. It is shown explicitly that a restriction to ρ meson (and therefore dilepton) production only in final-state baryon resonance decays provide a strong bias toward rather low baryon densities. The results presented are obtained from ultrarelativistic quantum molecular dynamics v2.3 calculations using the standard setup

Current status of baryon spectroscopy

International Nuclear Information System (INIS)

Wali, K.C.

1975-08-01

In this review of baryon spectroscopy, the basic ideas of some of the current models and the experimental data for their claims to success are discussed including realistic or constituent quark models, experimental comparison, the experimental and theoretical basis for the assignments, algebraic quark models, and confinement schemes

A Center for the Analyses of Electromagnetic and Hadronic Scattering

Energy Technology Data Exchange (ETDEWEB)

Briscoe, William [George Washington University, Washington, DC (United States)

2017-05-24

The GWU Institute for Nuclear Studies (GWINS) continued activities, and began new initiatives, within the context of a program of Hadronic Physics. The intense program of meson photoproduction measurements has resulted in an extensive set of observables that includes not only cross sections, but also polarization and double-polarization observables. Analysis of these new data contributes toward a resolution of a long-standing issue in baryon spectroscopy, namely, the “missing resonance" problem. The study of baryons containing two and three strange quarks (the Ξ and Ω states, respectively) has begun in order to solve this problem.

Modified Baryonic Dynamics: two-component cosmological simulations with light sterile neutrinos

Energy Technology Data Exchange (ETDEWEB)

Angus, G.W.; Gentile, G. [Department of Physics and Astrophysics, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050 Belgium (Belgium); Diaferio, A. [Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, Torino, I-10125 Italy (Italy); Famaey, B. [Observatoire astronomique de Strasbourg, CNRS UMR 7550, Université de Strasbourg, 11 rue de l' Université, Strasbourg, F-67000 France (France); Heyden, K.J. van der, E-mail: garry.angus@vub.ac.be, E-mail: diaferio@ph.unito.it, E-mail: benoit.famaey@astro.unistra.fr, E-mail: gianfranco.gentile@ugent.be, E-mail: heyden@ast.uct.ac.za [Astrophysics, Cosmology and Gravity Centre, Dept. of Astronomy, University of Cape Town, Private Bag X3, Rondebosch, 7701 South Africa (South Africa)

2014-10-01

In this article we continue to test cosmological models centred on Modified Newtonian Dynamics (MOND) with light sterile neutrinos, which could in principle be a way to solve the fine-tuning problems of the standard model on galaxy scales while preserving successful predictions on larger scales. Due to previous failures of the simple MOND cosmological model, here we test a speculative model where the modified gravitational field is produced only by the baryons and the sterile neutrinos produce a purely Newtonian field (hence Modified Baryonic Dynamics). We use two-component cosmological simulations to separate the baryonic N-body particles from the sterile neutrino ones. The premise is to attenuate the over-production of massive galaxy cluster halos which were prevalent in the original MOND plus light sterile neutrinos scenario. Theoretical issues with such a formulation notwithstanding, the Modified Baryonic Dynamics model fails to produce the correct amplitude for the galaxy cluster mass function for any reasonable value of the primordial power spectrum normalisation.

Baryon stopping and quark-gluon plasma production at RHIC and LHC

Energy Technology Data Exchange (ETDEWEB)

Lyakhov, K.

2008-08-15

Strong chromofields developed at early stages of relativistic heavy-ion collisions give rise to the collective deceleration of net baryons from colliding nuclei. We have solved classical equations of motion for baryonic slabs under the action of time-dependent chromofield. We have studied sensitivity of the slab trajectories and their final rapidities to the initial strength and decay pattern of the chromofield as well as to the back reaction of produced plasma. This mechanism can naturally explain significant baryon stopping observed at RHIC, an average rapidity loss left angle {delta}y right angle {approx} 2. Using a Bjorken hydrodynamical model with particle producing source we also study the evolution of partonic plasma produced as the result of chromofield decay. Due to the delayed formation and expansion of plasma its maximum energy density is much lower than the initial energy density of the chromofield. It is shown that the net-baryon and produced parton distributions are strongly correlated in the rapidity space. The shape of net-baryon spectra in midrapidity region found in the BRAHMS experiment cannot be reproduced by only one value of chromofield energy density parameter {epsilon}{sub 0}, even if one takes into account novel mechanisms as fluctuations of color charges generated on the slab surface, and weak interaction of baryon-rich matter with produced plasma. The further step to improve our results is to take into account rapidity dependence of saturation momentum as explained in thesis. Different values of parameter {epsilon}{sub 0} has been tried for different variants of chromofield decay to fit BRAHMS data for net-baryon rapidity distribution. In accordance with our analysis, data for fragmentation region correspond to the lower chromofield energy densities than mid-rapidity region. {chi}{sup 2} analysis favors power-law of chromofield decay with corresponding initial chromofield energy density of order {epsilon}{sub f}=30 GeV/fm{sup 3}. (orig.)

Measurement of the average polarization of b baryons in hadronic $Z^0$ decays

CERN Document Server

Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Bartoldus, R.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S.D.; Blobel, V.; Bloodworth, I.J.; Bobinski, M.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; del Pozo, L.A.; De Roeck, A.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Eatough, D.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Fabbri, F.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Hargrove, C.K.; Hartmann, C.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hobson, P.R.; Hocker, James Andrew; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nellen, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

1998-01-01

In the Standard Model, b quarks produced in e^+e^- annihilation at the Z^0 peak have a large average longitudinal polarization of -0.94. Some fraction of this polarization is expected to be transferred to b-flavored baryons during hadronization. The average longitudinal polarization of weakly decaying b baryons, , is measured in approximately 4.3 million hadronic Z^0 decays collected with the OPAL detector between 1990 and 1995 at LEP. Those b baryons that decay semileptonically and produce a \\Lambda baryon are identified through the correlation of the baryon number of the \\Lambda and the electric charge of the lepton. In this semileptonic decay, the ratio of the neutrino energy to the lepton energy is a sensitive polarization observable. The neutrino energy is estimated using missing energy measurements. From a fit to the distribution of this ratio, the value = -0.56^{+0.20}_{-0.13} +/- 0.09 is obtained, where the first error is statistical and the second systematic.

Heavy flavor baryons in hypercentral model

Indian Academy of Sciences (India)

periments have generated much interest in the spectroscopy of heavy flavor baryons ... the point of view of simple systems to study three-body problems. ..... One of the authors (PCV) acknowledges the financial support from the University.

Static properties of baryons in the SU(3) Skyrme model

International Nuclear Information System (INIS)

Sriram, M.S.; Mani, H.S.; Ramachandran, R.

1984-01-01

We study the SU(3) x SU(3) Skyrme model with explicit chiral- and flavor-symmetry-breaking terms. We evaluate the SU(3)-symmetric meson-baryon coupling-constant ratio α, SU(3) mass breaking in the octet and decuplet, and the ΔI = 1 part of the electromagnetic mass splitting in baryons. The theoretical numbers are in reasonable agreement with the experimental values

Axial charges of octet and decuplet baryons in a perturbative chiral quark model

Science.gov (United States)

Liu, X. Y.; Samart, D.; Khosonthongkee, K.; Limphirat, A.; Xu, K.; Yan, Y.

2018-05-01

Using the perturbative chiral quark model (PCQM), we investigate and predict in this work axial charges gAB of octet and decuplet N , Σ , Ξ , Δ , Σ*, and Ξ* baryons, considering both the ground and excited states in the quark propagator. The PCQM predictions are in good agreement with the experimental data, lattice-QCD values, and other approaches. In addition, the study reveals that the meson cloud is influential in the PCQM, contributing around 30% to the total values of gAB, and the meson cloud contribution to gAB stems mainly from the diagrams with the ground-state quark propagator while the excited intermediate quark states reduce gAB by 10-20%.

Determination of the average lifetime of b-baryons

CERN Document Server

Abreu, P; Adye, T; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barate, R; Barbi, M S; Bardin, Dimitri Yuri; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Buys, A; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Djama, F; Dolbeau, J; Dönszelmann, M; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gerdyukov, L N; Gibbs, M; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Grosdidier, G; Grzelak, K; Gumenyuk, S A; Gunnarsson, P; Günther, M; Guy, J; Hahn, F; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khokhlov, Yu A; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Köne, B; Kokkinias, P; Koratzinos, M; Korcyl, K; Kourkoumelis, C; Kuznetsov, O; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Merk, M; Meroni, C; Meyer, S; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Perrotta, A; Petridou, C; Petrolini, A; Petrovykh, M; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Pindo, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schimmelpfennig, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Solovyanov, O; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chikilev, O G; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Weierstall, M; Weilhammer, Peter; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Woschnagg, K; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G; Belokopytov, Yu; Charpentier, Ph; Gavillet, Ph; Gouz, Yu; Jarlskog, Ch; Khokhlov, Yu; Papadopoulou, Th D

1996-01-01

The average lifetime of b-baryons has been studied using 3 \\times 10^6 hadronic Z^0 decays collected by the DELPHI detector at LEP. Three methods have been used, based on the measurement of different observables: the proper decay time distribution of 206 vertices reconstructed with a \\Lambda, a lepton and an oppositely charged pion; the impact parameter distribution of 441 muons with high transverse momentum accompanied by a \\mLs in the same jet; and the proper decay time distribution of 125 \\Lambda_c-lepton decay vertices with the \\Lambda_c exclusively reconstructed through its pK\\pi, pK^0 and \\mLs3\\pi decay modes. The combined result is~:\\par \\begin{center} \\tau(b-baryon) = (1.25^{+0.13}_{-0.11}\\ pm0.04(syst)^{+0.03}_{-0. 05}(syst)) ps\\par \\end{center} where the first systematic error is due to experimental uncertainties and the second to the uncertainties in the modelling of the b-baryon production and semi-leptonic decay. Including the measurement recently published by DELPHI based on a sample of proton-m...

Baryonic 3P2-dominant superfluidity under combined pion condensation with Δ isobar. 1. Formulation

International Nuclear Information System (INIS)

Tamagaki, Ryozo

2006-01-01

Baryonic superfluidity is studied in the combined pion condensation with the Δ degrees of freedom. We adopt a model previously proposed, in which both condensates of the neutral and charged pions coexist without interference in neutron star matter above the nuclear density. In setting up the most probable pairing correlation in such situation, it is crucial to extract attractive effects of the baryon-baryon spin-orbit interaction playing a decisive role in realizing the superfluid at moderate high densities. To this aim, using the quasi-baryon basis having the good angular-momentum quantum number, we define the quasi-baryon pairs with the stretched two-dimensional angular momentum with m J =±2, being the sum of a spin component m s =±1 and an orbital-angular momentum m L =±1 of the quasi-baryon pairs. Pairing interaction is given in terms of the operators of these quasi-baryon pairs. This choice enables us to include the usual 3 P 2 pair as a dominant component in the quasi-baryon pairs thus defined. Then we rewrite the quasi-baryon pair operations in terms of the operators of the quasi-particles (denoted as η) describing the single-particle eigenmode in the combined pion condensation. The Bogoliubov transformation is performed according to the scheme previously developed in the study of the neutron 3 P 2 pairing, since both cases are similar in formal structure although different in physical content. Finally we obtain a coupled gap equation among three channels corresponding to three different charge states of the quasi-baryon pairs. This paper presents such a formulation. Analysis of the matrix element of the pairing interaction and numerical results of energy gaps will be reported in a succeeding paper. (author)

A diquark model for baryons containing one heavy quark

International Nuclear Information System (INIS)

Ebert, D.; Feldmann, T.; Kettner, C.; Reinhardt, H.

1995-06-01

We present a phenomenological ansatz for coupling a heavy quark with two light quarks to form a heavy baryon. The heavy quark is treated in the heavy mass limit, and the light quark dynamics is approximated by propagating scalar and axial vector 'diquarks'. The resulting effective lagrangian, which incorporates heavy quark and chiral symmetry, describes interactions of heavy baryons with Goldstone bosons in the low energy region. As an application, the Isgur-Wise formfactors are estimated. (orig.)

Proposal for the systematic naming of mesons and baryons

International Nuclear Information System (INIS)

Porter, F.C.; Hernandez, J.J.; Montanet, L.

1984-10-01

Twenty years ago, the Particle Data Group adopted a systematic naming convention for baryons: the symbols N, Δ, Λ, Σ, Ψ, and Ω were to identify the isospin and strangeness, The mesons, by contrast, have become an alphabet soup of uninformative names - theta, iota, xi, zeta, g/sub T/, g/sub s/, H, E, delta, h, g, r, kappa, etc. -, and in some cases identical names are used for mesons with different quantum numbers (A, B, and D). Furthermore, experimentalists are now discovering baryons that contain heavy quarks. It is therefore timely to consider systematic naming conventions both for mesons and for baryons with heavy quarks. The Particle Data Group is circulating this proposal in the hope of generating feedback, and we attach a sheet for responses. It should be emphasized that the Particle Tables would show both the old and new names for some time

What is the contribution of scattering to the Love-to-Rayleigh ratio in ambient microseismic noise?

Science.gov (United States)

Ziane, D.; Hadziioannou, C.

2015-12-01

Several observations show the existence of both Rayleigh and Love waves in the secondary microseism. While the Rayleigh wave excitation is well described by Longuet-Higgins, the process responsible for Love wave generation still needs further investigation. Several different mechanisms could excite Love waves in this frequency band: broadly speaking, we can differentiate between source effects, like pressure variations on the oblique sea floor, or internal effects in the medium along the propagation path, such as scattering and conversions. Here we will focus on the internal effects. We perform single scattering tests in 2D and 3D to gain a better understanding of the scattering radiation pattern and the conversion between P, S, Rayleigh and Love waves. Furthermore, we use random media with continuous variations of the elastic parameters to create a scattering regime similar to the Earths interior, e.g. Gaussian or von Karmann correlation functions. The aim is to explore the contribution of scattering along the propagation path to the observed Love to Rayleigh wave energy ratios, assuming a purely vertical force source mechanism. We use finite different solvers to calculate the synthetic seismograms, and to separate the different wave types we measure the rotational and divergent components of the wave field.

Predictions for Excited Strange Baryons

Energy Technology Data Exchange (ETDEWEB)

Fernando, Ishara P.; Goity, Jose L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2016-04-01

An assessment is made of predictions for excited hyperon masses which follow from flavor symmetry and consistency with a 1/N c expansion of QCD. Such predictions are based on presently established baryonic resonances. Low lying hyperon resonances which do not seem to fit into the proposed scheme are discussed.

A BARYONIC EFFECT ON THE MERGER TIMESCALE OF GALAXY CLUSTERS

International Nuclear Information System (INIS)

Zhang, Congyao; Yu, Qingjuan; Lu, Youjun

2016-01-01

Accurate estimation of the merger timescales of galaxy clusters is important for understanding the cluster merger process and further understanding the formation and evolution of the large-scale structure of the universe. In this paper, we explore a baryonic effect on the merger timescale of galaxy clusters by using hydrodynamical simulations. We find that the baryons play an important role in accelerating the merger process. The merger timescale decreases upon increasing the gas fraction of galaxy clusters. For example, the merger timescale is shortened by a factor of up to 3 for merging clusters with gas fractions of 0.15, compared with the timescale obtained with 0 gas fractions. The baryonic effect is significant for a wide range of merger parameters and is particularly more significant for nearly head-on mergers and high merging velocities. The baryonic effect on the merger timescale of galaxy clusters is expected to have an impact on the structure formation in the universe, such as the cluster mass function and massive substructures in galaxy clusters, and a bias of “no-gas” may exist in the results obtained from the dark matter-only cosmological simulations

Baryon Content in a Sample of 91 Galaxy Clusters Selected by the South Pole Telescope at 0.2 < z < 1.25

Energy Technology Data Exchange (ETDEWEB)

Chiu, I.; et al.

2017-11-02

We estimate total mass ($M_{500}$), intracluster medium (ICM) mass ($M_{\\mathrm{ICM}}$) and stellar mass ($M_{\\star}$) in a Sunyaev-Zel'dovich effect (SZE) selected sample of 91 galaxy clusters with masses $M_{500}\\gtrsim2.5\\times10^{14}M_{\\odot}$ and redshift $0.2 < z < 1.25$ from the 2500 deg$^2$ South Pole Telescope SPT-SZ survey. The total masses $M_{500}$ are estimated from the SZE observable, the ICM masses $M_{\\mathrm{ICM}}$ are obtained from the analysis of $Chandra$ X-ray observations, and the stellar masses $M_{\\star}$ are derived by fitting spectral energy distribution templates to Dark Energy Survey (DES) $griz$ optical photometry and $WISE$ or $Spitzer$ near-infrared photometry. We study trends in the stellar mass, the ICM mass, the total baryonic mass and the cold baryonic fraction with cluster mass and redshift. We find significant departures from self-similarity in the mass scaling for all quantities, while the redshift trends are all statistically consistent with zero, indicating that the baryon content of clusters at fixed mass has changed remarkably little over the past $\\approx9$ Gyr. We compare our results to the mean baryon fraction (and the stellar mass fraction) in the field, finding that these values lie above (below) those in cluster virial regions in all but the most massive clusters at low redshift. Using a simple model of the matter assembly of clusters from infalling groups with lower masses and from infalling material from the low density environment or field surrounding the parent halos, we show that the strong mass and weak redshift trends in the stellar mass scaling relation suggest a mass and redshift dependent fractional contribution from field material. Similar analyses of the ICM and baryon mass scaling relations provide evidence for the so-called 'missing baryons' outside cluster virial regions.

Two-pion exchange contributions to nuclear charge asymmetry

International Nuclear Information System (INIS)

Coon, S.A.; Niskanen, J.A.

1995-01-01

An explicit 2π exchange (TPE) potential based on non-relativistic πNN and πΔN vertices with the baryon mass differences taken into account in the vertices is extended to the study of mirror nuclear systems. For the latter study, one must also include baryon mass differences in the intermediate state energy denominators. The TPE potential includes box and crossed box diagrams with two nucleons and those with one nucleon and one Δ. Nuclear charge asymmetry is characterized, in part, by a positive value for the difference Δa = |a nn | - |a pp | ∼ O(1 fm) and a positive value for the 3 H - 3 He binding energy difference ΔE ∼ O(100 keV). The charge asymmetry from baryon mass differences in the vertices is small on this scale and in the wrong direction compared to the empirical values. The contribution from baryon mass differences in the intermediate state energy denominators is positive and is of the order of the empirical scales, in contrast to the previous estimate of Δa ∼ +0.3 fm obtained from an SU(2) symmetric covariant field theoretical potential. This discrepancy between models of TPE is being investigated

On the incompatibility of parity, baryon number and supersymmetries in hadron physics

International Nuclear Information System (INIS)

Grosser, D.

1976-01-01

Consider a theory with nontrivial S-matrix, nonvanishing masses and the property that to every mass belongs only a finite number of different types of particles. Suppose that it admits parity, baryon number and supersymmetries. It is shown that, if the theory accommodates a supermultiplet of hadrons and if all physically realizable vectors belonging to the mass of this supermultiplet represent hadrons, then the theory is inconsistent. In the derivation use is made of the experimental fact that hadrons have baryon number zero if they are bosons and baryon number +-1 if they are fermions

Heavy baryon chiral perturbation theory and the spin 3/2 delta resonances

Energy Technology Data Exchange (ETDEWEB)

Kambor, J.

1996-12-31

Heavy baryon chiral perturbation theory is briefly reviewed, paying particular attention to the role of the spin 3/2 delta resonances. The concept of resonance saturation for the baryonic sector is critically discussed. Starting from a relativistic formulation of the pion-nucleon-delta system, the heavy baryon chiral Lagrangian including spin 3/2 resonances is constructed by means of a 1/m-expansion. The effective theory obtained admits a systematic expansion in terms of soft momenta, the pion mass M{sub {pi}} and the delta-nucleon mass difference {Delta}. (author). 22 refs.

Derivation of sum rules for quark and baryon fields. [light-like charges

Energy Technology Data Exchange (ETDEWEB)

Bongardt, K [Karlsruhe Univ. (TH) (Germany, F.R.). Inst. fuer Theoretische Kernphysik

1978-08-21

In an analogous way to the Weinberg sum rules, two spectral-function sum rules for quark and baryon fields are derived by means of the concept of lightlike charges. The baryon sum rules are valid for the case of SU/sub 3/ as well as for SU/sub 4/ and the one-particle approximation yields a linear mass relation. This relation is not in disagreement with the normal linear GMO formula for the baryons. The calculated masses of the first resonance states agree very well with the experimental data.

Interactions between baryon octets by quark model

Energy Technology Data Exchange (ETDEWEB)

Nakamoto, S. [Suzuka National College of Technology, Suzuka, Mie (Japan); Fujiwara, Y. [Kyoto Univ., Faculty of Science, Kyoto (Japan); Suzuki, Y. [Niigata Univ., Faculty of Science, Niigata (Japan); Kohno, M. [Kyushu Dental College, Kita-kyushu, Fukuoka (Japan)

2003-03-01

Interactions between the baryon octets are studied by using the two spin flavor SU{sub 6} quark models, namely fss2 and FSS. In all channels, results that can be systematically understood along with the flavor symmetry are obtained. Effect of the channel coupling in the {sup 1}S{sub 0} state of the system of strangeness-2 shows a tendency to be weak in the system of isospin 0 while strong in the system of isospin 1. It is shown that this tendency is due to the competitive contributions of the color magnetic term and the effective meson exchange potential to the transition potential. Flavor symmetry breaking weakens both the repulsive force in the short range and the attractive force in the intermediate range. It is revealed that the overall qualitative behavior is determined as the result of the competitive effect of those interactions. (S. Funahashi)

Moduli induced cogenesis of baryon asymmetry and dark matter

Directory of Open Access Journals (Sweden)

Mansi Dhuria

2016-05-01

Full Text Available We study a cogenesis mechanism in which the observed baryon asymmetry of the universe and the dark matter abundance can be produced simultaneously at low reheating temperature without violating baryon number in the fundamental interactions. In particular, we consider a model which can be realized in the context of type IIB large volume string compactifications. The matter superfields in this model include additional pairs of color triplet and singlet superfields in addition to the Minimal Supersymmetric Standard Model (MSSM superfields. Assuming that the mass of the additional singlet fermions is O(GeV and of the color triplet fermions is O(TeV, we show that the modulus dominantly decays into the additional color triplet superfields. After soft supersymmetry (SUSY breaking, the lightest eigenstate of scalar component of color triplet superfield further decays into fermionic component of singlet superfield and quarks without violating baryon number. Imposing discrete Z2 symmetry, it follows that the singlet fermion will not further decay into the SM particles and therefore it can be considered as a stable asymmetric dark matter (ADM component. We find that the decay of the lightest eigenstate of scalar component of color triplet superfield gives the observed baryon asymmetry in the visible sector, an asymmetric dark matter component with the right abundance and naturally explains cosmic coincidence.

Chiral gravitational waves and baryon superfluid dark matter

Science.gov (United States)

Alexander, Stephon; McDonough, Evan; Spergel, David N.

2018-05-01

We develop a unified model of darkgenesis and baryogenesis involving strongly interacting dark quarks, utilizing the gravitational anomaly of chiral gauge theories. In these models, both the visible and dark baryon asymmetries are generated by the gravitational anomaly induced by the presence of chiral primordial gravitational waves. We provide a concrete model of an SU(2) gauge theory with two massless quarks. In this model, the dark quarks condense and form a dark baryon charge superfluid (DBS), in which the Higgs-mode acts as cold dark matter. We elucidate the essential features of this dark matter scenario and discuss its phenomenological prospects.

Gravitational coupling to two-particle bound states and momentum conservation in deep inelastic scattering

International Nuclear Information System (INIS)

Batiz, Zoltan; Gross, Franz

2000-01-01

The momentum conservation sum rule for deep inelastic scattering (DIS) from composite particles is investigated using the general theory of relativity. For two (1+1)-dimensional examples, it is shown that covariant theories automatically satisy the DIS momentum conservation sum rule provided the bound state is covariantly normalized. Therefore, in these cases the two DIS sum rules for baryon conservation and momentum conservation are equivalent. (c) 2000 The American Physical Society

About statistical process contribution to elastic diffraction scattering

International Nuclear Information System (INIS)

Ismanov, E.I.; Dzhuraev, Sh. Kh.; Paluanov, B.K.

1999-01-01

The experimental data on angular distribution show two basic properties. The first one is the presence of back and front peaks. The second one is the angular isotropic distribution near 90 degree, and has a big energy dependence. Different models for partial amplitudes a dl of the diffraction statistical scattering, particularly the model with Gaussian and exponential density distribution, were considered. The experimental data on pp-scattering were analyzed using the examined models

Energy loss, equilibration, and thermodynamics of a baryon rich strongly coupled quark-gluon plasma

Energy Technology Data Exchange (ETDEWEB)

Rougemont, Romulo [Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, Butantã, CEP 05508-090, São Paulo, SP (Brazil); Ficnar, Andrej [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Finazzo, Stefano I. [Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, Butantã, CEP 05508-090, São Paulo, SP (Brazil); Instituto de Física Teórica, Universidade do Estado de São Paulo, Rua Dr. Bento T. Ferraz, 271, CEP 01140-070, São Paulo, SP (Brazil); Noronha, Jorge [Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, Butantã, CEP 05508-090, São Paulo, SP (Brazil); Department of Physics, Columbia University, 538 West 120th Street, New York, NY 10027 (United States)

2016-04-15

Lattice data for the QCD equation of state and the baryon susceptibility near the crossover phase transition (at zero baryon density) are used to determine the input parameters of a 5-dimensional Einstein-Maxwell-Dilaton holographic model that provides a consistent holographic framework to study both equilibrium and out-of-equilibrium properties of a hot and baryon rich strongly coupled quark-gluon plasma (QGP). We compare our holographic equation of state computed at nonzero baryon chemical potential, μ{sub B}, with recent lattice calculations and find quantitative agreement for the pressure and the speed of sound for μ{sub B}≤400 MeV. This holographic model is used to obtain holographic predictions for the temperature and μ{sub B} dependence of the drag force and the Langevin diffusion coefficients associated with heavy quark jet propagation as well as the jet quenching parameter q̂ and the shooting string energy loss of light quarks in the baryon dense plasma. We find that the energy loss of heavy and light quarks generally displays a nontrivial, fast-varying behavior as a function of the temperature near the crossover. Moreover, energy loss is also found to generally increase due to nonzero baryon density effects even though this strongly coupled liquid cannot be described in terms of well defined quasiparticle excitations. Furthermore, to get a glimpse of how thermalization occurs in a hot and baryon dense QGP, we study how the lowest quasinormal mode of an external massless scalar disturbance in the bulk is affected by a nonzero baryon charge. We find that the equilibration time associated with the lowest quasinormal mode decreases in a dense medium.

Baryon number violation, baryogenesis, and defects with extra dimensions

International Nuclear Information System (INIS)

Matsuda, Tomohiro

2002-01-01

In generic models for grand unified theories (GUT), various types of baryon-number-violating processes are expected when quarks and leptons propagate in the background of GUT strings. On the other hand, in models with large extra dimensions, the baryon number violation in the background of a string is not trivial because it must depend on the mechanism of the proton stabilization. In this paper, we argue that cosmic strings in models with extra dimensions can enhance the baryon number violation to a phenomenologically interesting level, if the proton decay is suppressed by the mechanism of localized wave functions. We also make some comments on baryogenesis mediated by cosmological defects. We show that at least two scenarios will be successful in this direction. One is the scenario of leptogenesis where the required lepton number conversion is mediated by cosmic strings, and the other is the baryogenesis from the decaying cosmological domain wall. Both scenarios are new and have not been discussed in the past

Accurate initial conditions in mixed Dark Matter--Baryon simulations

CERN Document Server

Valkenburg, Wessel

2017-06-01

We quantify the error in the results of mixed baryon--dark-matter hydrodynamic simulations, stemming from outdated approximations for the generation of initial conditions. The error at redshift 0 in contemporary large simulations, is of the order of few to ten percent in the power spectra of baryons and dark matter, and their combined total-matter power spectrum. After describing how to properly assign initial displacements and peculiar velocities to multiple species, we review several approximations: (1) {using the total-matter power spectrum to compute displacements and peculiar velocities of both fluids}, (2) scaling the linear redshift-zero power spectrum back to the initial power spectrum using the Newtonian growth factor ignoring homogeneous radiation, (3) using longitudinal-gauge velocities with synchronous-gauge densities, and (4) ignoring the phase-difference in the Fourier modes for the offset baryon grid, relative to the dark-matter grid. Three of these approximations do not take into account that ...

B meson decays to baryons in the diquark model

International Nuclear Information System (INIS)

Chang, C.H.V.; Hou, W.S.

2002-01-01

We study B meson decays to two charmless baryons in the diquark model, including strong and electroweak penguins as well as the tree operators. It is shown that penguin operators can enhance anti B→B s anti B considerably, but affect anti B→B 1 anti B 2 only slightly, where B (1,2) and B s are non-strange and strange baryons, respectively. The γ dependence of the decay rates due to tree-penguin interference is illustrated. In principle, some of the B s anti B modes could dominate over B 1 anti B 2 for γ>90 , but in general the effect is milder than their mesonic counterparts. This is because the O 6 operator can only produce vector but not scalar diquarks, while the opposite is true for O 1 and O 4 . Predictions from the diquark model are compared to those from the sum rule calculation. The decays anti B→B s anti B s and inclusive baryonic decays are also discussed. (orig.)

Baryon production from cluster hadronisation

Energy Technology Data Exchange (ETDEWEB)

Gieseke, Stefan; Kirchgaesser, Patrick [Karlsruhe Institute of Technology, Institute for Theoretical Physics, Karlsruhe (Germany); Plaetzer, Simon [University of Vienna, Particle Physics, Faculty of Physics, Vienna (Austria)

2018-02-15

We present an extension to the colour reconnection model in the Monte Carlo event generator Herwig to account for the production of baryons and compare it to a series of observables for soft physics. The new model is able to improve the description of charged-particle multiplicities and hadron flavour observables in pp collisions. (orig.)

Relating the baryon asymmetry to the thermal relic dark matter density

International Nuclear Information System (INIS)