Baryon- and lepton-number non-conserving processes and intermediate mass scales
International Nuclear Information System (INIS)
Nieves, J.F.
1981-01-01
An analysis of the possible mechanisms to mediate various baryon- and lepton-number non-conserving processes is presented. Processes considered include the Δ(B+L) = 0 proton decay, ΔB = 2 neutron-antineutron oscillations and neutrino Majorana masses. Among our results we find that, in the absence of elementary scalars and exotic fermions, all the renormalizable interactions of vector bosons and ordinary fermions conserve B-L. Therefore, the observation of Δ(B-L) not equal 0 processes would imply the existence of elementary scalars and/or exotic fermions. (orig.)
Constrained instanton and baryon number non-conservation at high energies
International Nuclear Information System (INIS)
Sil'vestrov, P.G.
1992-01-01
The main subject of this paper is the calculation of corrections to instanton action ΔS∼(mρ) 4 log(mρ)/g 2 (ρ is the intanton radius) in the SU(2) Yang-Mills theory. The total cross section for baryon number violating processes at high energies is usually parametrized as σ tat ∝exp(4π/αF(ε)), where α=g 2 /4π, ε=√s/E 0 , E 0 =√6πm w /α. In the present paper the third nontrivial term of the F(ε) expansion is obtained. The unknown correction to F(ε) are expected to be of the order of ε 8/3 . The total cross section is extremely sensitive to the value of single instanton action. For sufficiently heavy Higgs boson the ρ-dependent part of the instanton action is changed drastically. 21 refs.; 1 fig
About the lepton number non conservation
International Nuclear Information System (INIS)
Bernabeu, J
1989-01-01
The possibility of lepton number non conservation through the mixing of lepton flavours, as well as the IΔLI=2 lepton antilepton conversion, is discussed. The paper follows the scheme: i) Experimental Situation; ii) Relation with the Neutrino Mass problem; iii) Majorana Neutrinos?; iv) Extensions of the Standard Model; v) Lepton Flavour Violating Decays of μ and τ; vi) Z∞ Boson Decays. (Author)
Baryon number violation and particle collider experiments
International Nuclear Information System (INIS)
Klinkhamer, F.R.; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica
1992-09-01
Baryon number non-conservation, due to non-perturbative effects (sphalerons) in the standard model, may have been important in the early Universe. In this paper the possibility is discussed that similar effects could show up at future particle collider experiments. (author). 16 refs.; 3 figs
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.
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
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
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.)
Family number non-conservation induced by the super-symmetric mixing of scalar leptons
International Nuclear Information System (INIS)
Levine, M.J.S.
1987-01-01
We examine a model of supersymmetry with soft breaking terms in the electroweak sector. Explicit mixing among the scalar leptons results in a number of effects, principally non-conservation of lepton family number. Comparison with experiment permits us to place constraints upon the model
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
Family number non-conservation induced by the supersymmetric mixing of scalar leptons
International Nuclear Information System (INIS)
Levine, M.J.S.
1987-08-01
The most egregious aspect of (N = 1) supersymmetric theories is that each particle state is accompanied by a 'super-partner', a state with identical quantum numbers save that it differs in spin by one half unit. For the leptons these are scalars and are called ''sleptons'', or scalar leptons. These consist of the charged sleptons (selectron, smuon, stau) and the scalar neutrinos ('sneutrinos'). We examine a model of supersymmetry with soft breaking terms in the electroweak sector. Explicit mixing among the scalar leptons results in a number of effects, principally non-conservation of lepton family number. Comparison with experiment permits us to place constraints upon the model. 49 refs., 12 figs
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
Formulation of baryon number violating collisions
International Nuclear Information System (INIS)
Funakubo, Koichi; Otsuki, Shoichiro; Takenaga, Kazunori; Toyoda, Fumihiko.
1992-01-01
A new formalism based on path-integral expression of time-evolution operator during tunneling is presented. Instead of instanton calculus in the LSZ formalism, a classical bounce solution leading to sphaleron (instanton action) at high (low) energies is adopted as the tunneling configuration. The formalism is applied to O(3) nonlinear sigma model in two dimensions. For the coupling constant g 2 ≅ 0.1, which may be physical in the sense that the number of produced particles ≅ 100, comparable with that of electroweak theory, the baryon number violating cross section is smaller by orders of magnitude than the so-called unitarity bound. (author)
Protecting the axion with local baryon number
Duerr, Michael; Schmidt-Hoberg, Kai; Unwin, James
2018-05-01
The Peccei-Quinn (PQ) solution to the Strong CP Problem is expected to fail unless the global symmetry U(1)PQ is protected from Planck-scale operators up to high mass dimension. Suitable protection can be achieved if the PQ symmetry is an automatic consequence of some gauge symmetry. We highlight that if baryon number is promoted to a gauge symmetry, the exotic fermions needed for anomaly cancellation can elegantly provide an implementation of the Kim-Shifman-Vainshtein-Zakharov 'hidden axion' mechanism with a PQ symmetry protected from Planck-scale physics.
Family number non-conservation induced by the supersymmetric mixing of scalar leptons
Energy Technology Data Exchange (ETDEWEB)
Levine, M.J.S.
1987-08-01
The most egregious aspect of (N = 1) supersymmetric theories is that each particle state is accompanied by a 'super-partner', a state with identical quantum numbers save that it differs in spin by one half unit. For the leptons these are scalars and are called ''sleptons'', or scalar leptons. These consist of the charged sleptons (selectron, smuon, stau) and the scalar neutrinos ('sneutrinos'). We examine a model of supersymmetry with soft breaking terms in the electroweak sector. Explicit mixing among the scalar leptons results in a number of effects, principally non-conservation of lepton family number. Comparison with experiment permits us to place constraints upon the model. 49 refs., 12 figs.
Baryon number violation in high energy collisions
International Nuclear Information System (INIS)
Farrar, G.R.; Meng, R.
1990-08-01
We study the phenomenology of baryon number violation induced by electroweak instantons. We find that if the naive-instanton amplitudes were valid for arbitrarily high energies, the event rate at the SSC would be a few per hour, with a typical event consisting of 3 'primary' antileptons and 7 'primary' antiquark jets, accompanied by ≅ 85 electroweak gauge bosons, having a sharp threshold in the total sub-energy at about 17 TeV. We describe how to establish their electroweak-instanton-induced origin. The naive instanton approximation is known to overestimate the rate for these processes, so this work focusses attention on the need for more accurate calculations, and for a calculational method which is appropriate when the energy of the initial particles is above the sphaleron energy. (orig.)
Gauge theory for baryon and lepton numbers with leptoquarks.
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.
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.)
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.
The quark mass and baryon numbers of empty chiral bags
International Nuclear Information System (INIS)
Jezabek, M.; Zalewski, K.
1984-01-01
We show that for spherical chiral bags the baryon number of the Dirac vacuum inside the bag does not depend on quark masses. Thus, the sum of the baryon numbers of an empty chiral bag and the skyrmion surrounding the bag is an integer, which depends on the boundary condition on the surface of the bag. This extends the result obtained by Goldstone and Jaffe for massless quarks. (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
Baryon number dissipation at finite temperature in the standard model
International Nuclear Information System (INIS)
Mottola, E.; Raby, S.; Starkman, G.
1990-01-01
We analyze the phenomenon of baryon number violation at finite temperature in the standard model, and derive the relaxation rate for the baryon density in the high temperature electroweak plasma. The relaxation rate, γ is given in terms of real time correlation functions of the operator E·B, and is directly proportional to the sphaleron transition rate, Γ: γ preceq n f Γ/T 3 . Hence it is not instanton suppressed, as claimed by Cohen, Dugan and Manohar (CDM). We show explicitly how this result is consistent with the methods of CDM, once it is recognized that a new anomalous commutator is required in their approach. 19 refs., 2 figs
Asymmetric dark matter, baryon asymmetry and lepton number violation
Frandsen, Mads T.; Hagedorn, Claudia; Huang, Wei-Chih; Molinaro, Emiliano; Päs, Heinrich
2018-01-01
We study the effect of lepton number violation (LNV) on baryon asymmetry, generated in the early Universe, in the presence of a dark sector with a global symmetry U(1)X , featuring asymmetric dark matter (ADM). We show that in general LNV, observable at the LHC or in neutrinoless double beta decay experiments, cannot wash out a baryon asymmetry generated at higher scales, unlike in scenarios without such dark sector. An observation of LNV at the TeV scale may thus support ADM scenarios. Consi...
Baryon-plus-lepton number violation at high temperatures for arbitrary Higgs mass
International Nuclear Information System (INIS)
Li, Xu.
1992-01-01
In this thesis, baryon-plus lepton (B + L) number violation in the electroweak theory of the Weinberg-Salam model is systematically studied. B + L number non-conservation in the electroweak theory is believed to be a consequence of the axial U(1) anomaly. It is argued that sphaleron, not instanton dominates the topological vacuum-to-vacuum transitions for B + L number change at high temperatures. The rate of change is reduced to a dimensionless prefactor κ which is related to the determinants of small fluctuations around the sphaleron configuration. And κ is exactly computed at high temperatures exploiting symmetries of sphaleron under spatial rotations combined with isospin and custodial SU(2) transformations. For the ratio λ/g 2 of scalar four point coupling λ to gauge coupling g 2 near unity, it is found that κ is 0.03 and the rate of B + L number change at temperatures of order 1 Tev is about 8 to 9 orders of magnitude faster than the expansion rate of the big band theory. For λ/g 2 very small tending to the Coleman-Weinberg limit, it is found that the determinant strongly suppresses the rate of baryon number changing processes
On the vacuum baryon number in the chiral bag model
International Nuclear Information System (INIS)
Jaroszewicz, T.
1984-01-01
We give a rederivation, generalization and interpretation of the result of Goldstone and Jaffe on the vacuum baryon number in the chiral bag model. Our results are based on considering the bag model as a theory of free quarks, massless inside and infinitely massive outside the bag. (orig.)
Baryon number nonconservation in extreme conditions
International Nuclear Information System (INIS)
Matveev, V.A.; Rubakov, V.A.; Tavkhelidze, A.N.; Shaposhnikov, M.E.
1988-01-01
In gauge theories with the left-right asymmetric fermionic content (e.g. in standard electroweak theory) fermion number F is not conserved due to the anomaly. It is shown that anomalous processes, while being exponentially suppressed, under normal conditions, are in fact rapid. The mechanism of fermionic number nonconservation connected with a level crossing phenomenon in external gauge fields is described. The theory and experimental consequences of monopole catalysis of a proton decay is reviewed. It is shown that cold dense fermionic matter is stable only up to some limiting density. It is demonstrated that there is no exponential suppression of the rate F nonconservation at high temperatures. The cosmological implications of this fact are discussed. The strong anomalous fermionic number violation in decays of superheavy fermions technibaryons is considered
Fermion number non-conservation and cold neutral fermionic matter in (V-A) gauge theories
International Nuclear Information System (INIS)
Matveev, V.A.; Rubakov, V.A.; Tavkhelidze, A.N.; Tokarev, V.F.
1987-01-01
It is shown that in four-dimensional abelian (V-A) theories, the ground state of cold neutral fermionic matter is an anomalous state containing domains of abnormal phase surrounded by the normal vacuum. Inside these domains, there exists a gauge field condensate which makes real fermions disappear both inside and outside the domains. In non-abelian theories, the abnormal matter is unstable in its turn, and the system rolls back down into the normal state with a small number of fermions above the topologically non-trivial vacuum. Thus, in several non-abelian gauge theories, the fermion number density of cold neutral matter cannot exceed some critical value. (orig.)
An update on MEGA: An experimental search for lepton number non-conservation
International Nuclear Information System (INIS)
Hungerford, E.V.
1998-01-01
Mega is an experiment to search for the decay μ→eγ. It is designed to test lepton-number conservation in muon decay by a background free measurement in this branching ratio at a sensitivity of a few x10 -13 . This paper reports particularly on the design and performance of the MEGA detector, as the lessons learned previously are important when new experiments are proposed which would increase the sensitivity of such a measurement down to a branching ratio on the order of 10 -14 . copyright 1998 American Institute of Physics
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
Baryon number fluctuations in quasi-particle model
Energy Technology Data Exchange (ETDEWEB)
Zhao, Ameng [Southeast University Chengxian College, Department of Foundation, Nanjing (China); Luo, Xiaofeng [Central China Normal University, Key Laboratory of Quark and Lepton Physics (MOE), Institute of Particle Physics, Wuhan (China); Zong, Hongshi [Nanjing University, Department of Physics, Nanjing (China); Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing (China); Institute of Theoretical Physics, CAS, State Key Laboratory of Theoretical Physics, Beijing (China)
2017-04-15
Baryon number fluctuations are sensitive to the QCD phase transition and the QCD critical point. According to the Feynman rules of finite-temperature field theory, we calculated various order moments and cumulants of the baryon number distributions in the quasi-particle model of the quark-gluon plasma. Furthermore, we compared our results with the experimental data measured by the STAR experiment at RHIC. It is found that the experimental data can be well described by the model for the colliding energies above 30 GeV and show large discrepancies at low energies. This puts a new constraint on the qQGP model and also provides a baseline for the QCD critical point search in heavy-ion collisions at low energies. (orig.)
Baryon number violation and novel canonical anti-commutation relations
Fujikawa, Kazuo; Tureanu, Anca
2018-02-01
The possible neutron-antineutron oscillation is described by an effective quadratic Lagrangian analogous to the BCS theory. It is shown that the conventional equal-time anti-commutation relations of the neutron variable n (t , x →) are modified by the baryon number violating terms. This is established by the Bjorken-Johnson-Low prescription and also by the canonical quantization combined with equations of motion. This novel canonical behavior can give rise to an important physical effect, which is illustrated by analyzing the Lagrangian that violates the baryon number but gives rise to the degenerate effective Majorana fermions and thus no neutron-antineutron oscillation. Technically, this model is neatly treated using a relativistic analogue of the Bogoliubov transformation.
Light U(1) gauge boson coupled to baryon number
International Nuclear Information System (INIS)
Carone, C.D.; Murayama, Hitoshi
1995-06-01
The authors discuss the phenomenology of a light U(1) gauge boson, γ B , that couples only to baryon number. Gauging baryon number at high energies can prevent dangerous baryon-number violating operators that may be generated by Planck scale physics. However, they assume at low energies that the new U(1) gauge symmetry is spontaneously broken and that the γ B mass m B is smaller than m z . They show for m Υ B z that the γB coupling α B can be as large as ∼ 0.1 without conflicting with the current experimental constraints. The authors argue that α B ∼ 0.1 is large enough to produce visible collider signatures and that evidence for the γ B could be hidden in existing LEP data. They show that there are realistic models in which mixing between the γ B and the electroweak gauge bosons occurs only as a radiative effect and does not lead to conflict with precision electroweak measurements. Such mixing may nevertheless provide a leptonic signal for models of this type at an upgraded Tevatron
Search for Baryon and Lepton Number Violating $Z^0$ Decays
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.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; 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.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Eatough, D.; Estabrooks, P.G.; Etzion, E.; 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.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; 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.; Hobson, P.R.; Hoch, M.; Hocker, James Andrew; Hoffman, Kara Dion; 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.; Kim, D.H.; 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.; Landsman, H.; 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.; Spagnolo, 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.; Thomas, J.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; 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.
1999-01-01
Using data collected with the OPAL detector at LEP, we have searched for the processes e+e- -> Z0 -> p e-, p mu- and the charge conjugate final-states. These would violate the conservation of the baryon-number B, lepton-number L and the fermion-number n = (B+L). No evidence for such decays has been found, and the 95% confidence level upper limits on the partial widths Z0 -> p e and Z0 -> p mu are found to be 4.6 and 4.4 keV respectively.
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.)
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.
New topological structures of Skyrme theory: baryon number and monopole number
Energy Technology Data Exchange (ETDEWEB)
Cho, Y.M. [Chinese Academy of Science, Institute of Modern Physics, Lanzhou (China); Konkuk University, Seoul (Korea, Republic of); Seoul National University, School of Physics and Astronomy, Seoul (Korea, Republic of); Kimm, Kyoungtae [Seoul National University, Faculty of Liberal Education, Seoul (Korea, Republic of); Yoon, J.H. [Konkuk University, Department of Physics, Seoul (Korea, Republic of); Zhang, Pengming [Chinese Academy of Science, Institute of Modern Physics, Lanzhou (China)
2017-02-15
Based on the observation that the skyrmion in Skyrme theory can be viewed as a dressed monopole, we show that the skyrmions have two independent topology, the baryon topology π{sub 3}(S{sup 3}) and the monopole topology π{sub 2}(S{sup 2}). With this we propose to classify the skyrmions by two topological numbers (m, n), the monopole number m and the shell (radial) number n. In this scheme the popular (non spherically symmetric) skyrmions are classified as the (m, 1) skyrmions but the spherically symmetric skyrmions are classified as the (1, n) skyrmions, and the baryon number B is given by B = mn. Moreover, we show that the vacuum of the Skyrme theory has the structure of the vacuum of the Sine-Gordon theory and QCD combined together, which can also be classified by two topological numbers (p, q). This puts the Skyrme theory in a totally new perspective. (orig.)
Symmetry mappings concomitant to particle-number-conservation-baryon-number conservation
International Nuclear Information System (INIS)
Davis, W.R.
1977-01-01
Four theorem serve to demonstrate that matter fields in space-time admit certain timelike symmetry mappings concomitant to the familiar notion of particle number conservation, which can be more fundamentally accounted for by a type of projective invariance principle. These particular symmetry mappings include a family of symmetry properties that may be admitted by Riemannian space-times. In their strongest form, the results obtained provide some insight relating to the conservation of baryon number
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
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
Exotic dynamically generated baryons with negative charm quantum number
Gamermann, D.; Garcia-Recio, C.; Nieves, J.; Salcedo, L. L.; Tolos, L.
2010-01-01
Following a model based on the SU(8) symmetry that treats heavy pseudoscalars and heavy vector mesons on an equal footing, as required by heavy quark symmetry, we study the interaction of baryons and mesons in coupled channels within an unitary approach that generates dynamically poles in the
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.)
arXiv Search for baryon-number-violating $\\Xi_b^0$ oscillations
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.
Fluid dynamic propagation of initial baryon number perturbations on a Bjorken flow background
Floerchinger, Stefan
2015-01-01
Baryon number density perturbations offer a possible route to experimentally measure baryon number susceptibilities and heat conductivity of the quark gluon plasma. We study the fluid dynamical evolution of local and event-by-event fluctuations of baryon number density, flow velocity and energy density on top of a (generalized) Bjorken expansion. To that end we use a background-fluctuation splitting and a Bessel-Fourier decomposition for the fluctuating part of the fluid dynamical fields with respect to the azimuthal angle, the radius in the transverse plane and rapidity. We examine how the time evolution of linear perturbations depends on the equation of state as well as on shear viscosity, bulk viscosity and heat conductivity for modes with different azimuthal, radial and rapidity wave numbers. Finally we discuss how this information is accessible to experiments in terms of the transverse and rapidity dependence of correlation functions for baryonic particles in high energy nuclear collisions.
Search for Baryon-Number Violating Ξ_{b}^{0} Oscillations.
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.
Sphaleron-induced baryon-number nonconservation and a constraint on Majorana neutrino masses
International Nuclear Information System (INIS)
Fukugita, M.; Yanagida, T.
1990-01-01
We point out that the baryon-number asymmetry in the Universe is erased by the sphaleron effect just below the electroweak phase transition irrespective of the primordial baryon- and lepton-number asymmetry, if there exists a Majorana-type interaction. The requirement to avoid this happening leads to the condition that m ν (Majorana) <50 keV for all species of neutrinos, regardless of whether or not neutrinos are stable
The Baryon Number Two System in the Chiral Soliton Model
International Nuclear Information System (INIS)
Mantovani-Sarti, V.; Drago, A.; Vento, V.; Park, B.-Y.
2013-01-01
We study the interaction between two B = 1 states in a chiral soliton model where baryons are described as non-topological solitons. By using the hedgehog solution for the B = 1 states we construct three possible B = 2 configurations to analyze the role of the relative orientation of the hedgehog quills in the dynamics. The strong dependence of the inter soliton interaction on these relative orientations reveals that studies of dense hadronic matter using this model should take into account their implications. (author)
Separate μ- and e-lepton numbers non-conservation in the Weinberg model with two higgs doublets
International Nuclear Information System (INIS)
Branco, G.C.
1977-03-01
It is shown that in the Weinberg-Salam model with two Higgs doublets, one is naturally led to the violation of separate μ and e-lepton numbers. The branching ratio for μ → eγ is found to be comparable to the present experimental limit. (orig.) [de
International Nuclear Information System (INIS)
Szymanski, P.
2006-09-01
This work concerns soft hadronic interactions which in the Standard Model carry most of the observable cross-section but are not amenable to quantitative predictions due to the very nature of the QCD (Theory of Strong Interactions). In the low momentum transfer region the evolving coupling constant caused perturbation theory to break down. In this situation better experimental understanding of the physics phenomena is needed. One aspect of the soft hadronic interactions will be discussed in this work: transfer of the baryon number from the initial to the final state of the interaction. The past experimental knowledge on this process is presented, reasons for its unsatisfactory status are discussed and condition necessary for improvement are outlined: that is experimental apparatus with superior performance over the full range of available interactions: hadron-hadron collision, hadron-nucleus and nucleus-nucleus interactions. A consistent model-independent picture of the baryon number transfer process emerging from the data on the full range of interactions is shown. It offers serious challenge to theory to provide quantitative and detailed explanation of the measurements. (author)
The quenched limit of lattice QCD at non-zero baryon number
International Nuclear Information System (INIS)
Engels, J.; Kaczmarek, O.; Karsch, F.; Laermann, E.
1999-01-01
We discuss the thermodynamics of gluons in the background of static quark sources. In order to do so we formulate the quenched limit of QCD at non-zero baryon number. A first numerical analysis of this system shows that it undergoes a smooth deconfining transition. We find evidence for a region of coexisting phases that becomes broader with increasing baryon number density. Although the action is in our formulation explicitly Z(3) symmetric the Polyakov loop expectation value becomes non-zero already in the low temperature phase. It indicates that the heavy quark potential stays finite at large distances, i.e. the string between static quarks breaks at non-zero baryon number density already in the hadronic phase
Sphalerons, small fluctuations, and baryon-number violation in electroweak theory
International Nuclear Information System (INIS)
Arnold, P.; McLerran, L.
1987-01-01
We study the formalism of the sphaleron approximation to baryon-number violation in the standard model at temperatures near 1 TeV. We investigate small fluctuations of the sphaleron, the competition of large-scale sphalerons with thermal fluctuations, and the damping of the transition rate in the plasma. We find a suppression of the rate due to Landau damping and due to factors arising from zero modes. Our approximations are valid in the regime 2M/sub W/(T) 2 . We find that the rate of baryon-number violation is still significantly larger than the expansion rate of the Universe
Implications of horizontal symmetries on baryon number violation in supersymmetric models
International Nuclear Information System (INIS)
Ben-Hamo, V.; Nir, Y.
1994-08-01
The smallness of the quark and lepton parameters and the hierarchy between them could be the result of selection rules due to a horizontal symmetry broken by a small parameter. The same selection rules apply to baryon number violating terms. Consequently, the problem of baryon number violation in supersymmetry may be solved naturally, without invoking any especially-designed extra symmetry. This mechanism is efficient enough even for low-scale flavor physics. Proton decay is likely to be dominated by the modes K + ν-bar i or K o μ + (e + ), and may proceed at observable rates. (authors). 15 refs
Baryon and lepton number violation in the Weinberg-Salam theory
International Nuclear Information System (INIS)
Mottola, E.
1989-01-01
This report discusses the concept of baryon and lepton number violation in the Weinberg-Salam theory. The topics discussed are: periodic vacua in quantum mechanics; tunnelling at finite temperature and classical thermal activation; calculation of the rate; an O(3) nonlinear sigma model; and the transition rate in the O(3) model
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.
McCracken, M. E.; Bellis, M.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Pereira, S. Anefalos; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.
2015-01-01
We present a search for ten baryon-number violating decay modes of $\\Lambda$ hyperons using the CLAS detector at Jefferson Laboratory. Nine of these decay modes result in a single meson and single lepton in the final state ($\\Lambda \\rightarrow m \\ell$) and conserve either the sum or the difference of baryon and lepton number ($B \\pm L$). The tenth decay mode ($\\Lambda \\rightarrow \\bar{p}\\pi^+$) represents a difference in baryon number of two units and no difference in lepton number. We obser...
Baryon and lepton number violation in the electroweak theory at TeV energies
International Nuclear Information System (INIS)
Mottola, E.
1990-01-01
In the standard Weinberg-Salam electroweak theory baryon and lepton number (B and L) are NOT exactly conserved. The nonconservation of B and L can be traced to the existence of parity violation in the electroweak theory, together with the chiral current anomaly. This subtle effect gives negligibly small amplitudes for B and L violation at energies and temperatures significantly smaller than M w sin 2 θ w /α ∼ 10 TeV. However, recent theoretical work shows that the rate for B and L nonconservation is unsuppressed at higher energies. The consequences of this for cosmology and the baryon asymmetry of the universe, as well as the prospects for direct verification at the SSC are discussed. 13 refs., 3 figs
The quark-hadron transition in systems with net baryon number
International Nuclear Information System (INIS)
Olive, K.A.; Harvard Univ., Cambridge, MA
1982-01-01
The transition from quark matter to hadronic matter is examined in systems with arbitrary chemical potentials corresponding to net baryon number. In the hardron phase, both a Reid-type potential for nucleons and the ππ potential derived from Weinberg's effective lagrangian have been included. In the quark phase, a linear confining potential has been considered. Results are most sensitive to the slope of the confining potential, although qualitatively the behavior of the thermodynamic properties remain unchanged. The critical baryon density is found to remain roughly constant for all temperatures below the critical temperature, Tsub(c), then falls rapidly to zero as T → Tsub(c). Below Tsub(c) this density is about 30n 0 for K = 0.18 GeV 2 (the slope of the quark potential) and 23n 0 for K = 0.10 GeV 2 . (orig.)
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.)
Shuryak, E. V.; Verbaarschot, J. J. M.
1992-04-01
Baryon number violation and multiple production of W and Higgs bosons are described semiclassically in terms of the instanton-anti-instanton valley. We find (i) two saddle points, one describing reflection from a barrier and the other describing tunneling through it. We find (ii) a critical energy Ec~35 TeV where the cross section is suppressed as exp(-const/g2w), but the formulas are no longer valid; (iii) however, depending on the (still uncertain) Higgs bosson action, the cross section at this point may be large enough to be observable.
Allahverdi, Rouzbeh; Dev, P. S. Bhupal; Dutta, Bhaskar
2018-04-01
We study a simple TeV-scale model of baryon number violation which explains the observed proximity of the dark matter and baryon abundances. The model has constraints arising from both low and high-energy processes, and in particular, predicts a sizable rate for the neutron-antineutron (n - n bar) oscillation at low energy and the monojet signal at the LHC. We find an interesting complementarity among the constraints arising from the observed baryon asymmetry, ratio of dark matter and baryon abundances, n - n bar oscillation lifetime and the LHC monojet signal. There are regions in the parameter space where the n - n bar oscillation lifetime is found to be more constraining than the LHC constraints, which illustrates the importance of the next-generation n - n bar oscillation experiments.
Perturbation theory of the quark-gluon plasma at finite temperature and baryon number density
International Nuclear Information System (INIS)
Anon.
1984-01-01
At very high energy densities, hadronic matter becomes an almost ideal gas of quarks and gluons. In these circumstances, the effects of particle interactions are small, and to some order in perturbation theory are computable by methods involving weak coupling expansions. To illustrate the perturbative methods which may be used to compute the thermodynamic potential, the results and methods which are employed to compute to first order in α/sub s/ are reviewed. The problem of the plasmon effect, and the necessity of using non-perturbative methods when going beyond first order in α/sub s/ in evaluating the thermodynamic potential are discussed. The results at zero temperature and finite baryon number density to second order in α/sub s/ are also reviewed. The method of renormalization group improving the weak coupling expansions by replacing the expansion by an expansion in a temperature and baryon number density dependent coupling which approaches zero at high energy densities is discussed. Non-perturbative effects such as instantons are briefly mentioned and the breakdown of perturbation theory for the thermodynamical at order α/sub s/ 3 for finite temperature is presented
Anomalies, sphalerons and baryon number violation in electro-weak theory
International Nuclear Information System (INIS)
Mclerran, L.
1989-01-01
In series of three lectures, baryon number violation at high temperatures in the Weinberg-Salam model is discussed. The first lecture presents a discussion of anomalies, and how this is related to level crossing of energy levels in the Dirac equation for fermions in an external field. The second lecture discusses topological aspects of the Weinberg-Salam theory, and some related two dimensional models. The sphaleron solution of these theories is constructed. In the final lecture, the sphaleron is related to transition rates at finite temperature. In a simple quantum mechanics model, it is shown that sphalerons, not instantons, are responsible for transitions at high temperature. The sphaleron induced rate is then discussed in a solvable 1+1 dimensional model, which has many similarities to the Weinberg-Salam model. Finally, the result for the Weinberg-Salam model is derived and is shown to be large for temperatures T ≥ 1 TeV. 35 refs., 9 figs. (author)
McCracken, M. E.; Bellis, M.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Pereira, S. Anefalos; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Dupre, R.; Alaoui, A. El; Fassi, L. El; Elouadrhiri, E.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Filippi, A.; Fleming, J. A.; Garillon, B.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mayer, M.; McKinnon, B.; Mestayer, M. D.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Moody, C. I.; Moriya, K.; Camacho, C. Munoz; Nadel-Turonski, P.; Net, L. A.; Niccolai, S.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Sokhan, D.; Sparveris, N.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Tian, Ye; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration
2015-10-01
We present a search for ten baryon number violating decay modes of Λ hyperons using the CLAS detector at Jefferson Laboratory. Nine of these decay modes result in a single meson and single lepton in the final state (Λ →m ℓ) and conserve either the sum or the difference of baryon and lepton number (B ±L ). The tenth decay mode (Λ →p ¯ π+ ) represents a difference in baryon number of two units and no difference in lepton number. We observe no significant signal and set upper limits on the branching fractions of these reactions in the range (4 - 200 )×10-7 at the 90% confidence level.
Searches for violation of lepton flavour and baryon number in tau lepton decays at LHCb
Energy Technology Data Exchange (ETDEWEB)
Aaij, R. [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands); Abellan Beteta, C. [Universitat de Barcelona, Barcelona (Spain); Adeva, B. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Adinolfi, M. [H.H. Wills Physics Laboratory, University of Bristol, Bristol (United Kingdom); Adrover, C. [CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille (France); Affolder, A. [Oliver Lodge Laboratory, University of Liverpool, Liverpool (United Kingdom); Ajaltouni, Z. [Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC, Clermont-Ferrand (France); Albrecht, J. [Fakultät Physik, Technische Universität Dortmund, Dortmund (Germany); Alessio, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Alexander, M. [School of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom); Ali, S. [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands); Alkhazov, G. [Petersburg Nuclear Physics Institute (PNPI), Gatchina (Russian Federation); Alvarez Cartelle, P. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Alves, A.A. [Sezione INFN di Roma La Sapienza, Roma (Italy); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Amato, S. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro (Brazil); Amerio, S. [Sezione INFN di Padova, Padova (Italy); Amhis, Y. [LAL, Université Paris-Sud, CNRS/IN2P3, Orsay (France); Anderlini, L. [Sezione INFN di Firenze, Firenze (Italy); Anderson, J. [Physik-Institut, Universität Zürich, Zürich (Switzerland); Andreassen, R. [University of Cincinnati, Cincinnati, OH (United States); and others
2013-07-09
Searches for the lepton flavour violating decay τ{sup −}→μ{sup −}μ{sup +}μ{sup −} and the lepton flavour and baryon number violating decays τ{sup −}→p{sup ¯}μ{sup +}μ{sup −} and τ{sup −}→pμ{sup −}μ{sup −} have been carried out using proton–proton collision data, corresponding to an integrated luminosity of 1.0 fb{sup −1}, taken by the LHCb experiment at √(s)=7 TeV. No evidence has been found for any signal, and limits have been set at 90% confidence level on the branching fractions: B(τ{sup −}→μ{sup −}μ{sup +}μ{sup −})<8.0×10{sup −8}, B(τ{sup −}→p{sup ¯}μ{sup +}μ{sup −})<3.3×10{sup −7} and B(τ{sup −}→pμ{sup −}μ{sup −})<4.4×10{sup −7}. The results for the τ{sup −}→p{sup ¯}μ{sup +}μ{sup −} and τ{sup −}→pμ{sup −}μ{sup −} decay modes represent the first direct experimental limits on these channels.
New fermion mass textures from anomalous U(1) symmetries with baryon and lepton number conservation
Leontaris, George K
2000-01-01
In this paper, we present solutions to the fermion mass hierarchy problem in the context of the minimal supersymmetric standard theory augmented by an anomalous family-dependent U(1)_X symmetry. The latter is spontaneously broken by non-zero vevs of a pair of singlet fields whose magnitude is determined through the D- and F-flatness conditions of the superpotential. We derive the general solutions to the anomaly cancellation conditions and show that they allow numerous choices for the U(1)_X fermion charges which give several fermion mass textures in agreement with the observed fermion mass hierarchy and mixing. Solutions with U(1)_X fermion charge assignments are found which forbid or substantially suppress the dangerous baryon and lepton number violating operators and the lepton-higgs mixing coupling while a higgs mixing mass classification of the fermion mass textures with respect to the sum of the doublet-higgs U(1)_X-charges and show that suppression of dimension-five operators naturally occurs for vario...
Searches for violation of lepton flavour and baryon number in tau lepton decays at LHCb
Aaij, R; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves Jr, A A; Amato, S; Amerio, S; Amhis, Y; Anderlini, L; Anderson, J; Andreassen, R; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Baesso, C; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bauer, Th; Bay, A; Beddow, J; Bedeschi, F; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M -O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bowen, E; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Burducea, I; Bursche, A; Busetto, G; Buytaert, J; Cadeddu, S; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carranza-Mejia, H; Carson, L; Carvalho Akiba, K; Casse, G; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Charles, M; Charpentier, Ph; Chen, P; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coca, C; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Couturier, B; Cowan, G A; Craik, D C; Cunliffe, S; Currie, R; D'Ambrosio, C; David, P; David, P N Y; Davis, A; De Bonis, I; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Silva, W; De Simone, P; Decamp, D; Deckenhoff, M; Del Buono, L; Déléage, N; Derkach, D; Deschamps, O; Dettori, F; Di Canto, A; Di Ruscio, F; Dijkstra, H; Dogaru, M; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Elsby, D; Falabella, A; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Ferguson, D; Fernandez Albor, V; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fiore, M; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Furcas, S; Furfaro, E; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garofoli, J; Garosi, P; Garra Tico, J; Garrido, L; Gaspar, C; Gauld, R; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Griffith, P; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hampson, T; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hartmann, T; He, J; Heijne, V; Hennessy, K; Henrard, P; Hernando Morata, J A; van Herwijnen, E; Hicks, E; Hill, D; Hoballah, M; Hombach, C; Hopchev, P; Hulsbergen, W; Hunt, P; Huse, T; Hussain, N; Hutchcroft, D; Hynds, D; Iakovenko, V; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jans, E; Jaton, P; Jing, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Kaballo, M; Kandybei, S; Karacson, M; Karbach, T M; Kenyon, I R; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kochebina, O; Komarov, I; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kucharczyk, M; Kudryavtsev, V; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J -P; Lefèvre, R; Leflat, A; Lefrançois, J; Leo, S; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Li Gioi, L; Liles, M; Lindner, R; Linn, C; Liu, B; Liu, G; Lohn, S; Longstaff, I; Lopes, J H; Lopez Asamar, E; Lopez-March, N; Lu, H; Lucchesi, D; Luisier, J; Luo, H; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Malde, S; Manca, G; Mancinelli, G; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martin, L; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Maurice, E; Mazurov, A; McCarthy, J; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Merk, M; Milanes, D A; Minard, M -N; Molina Rodriguez, J; Monteil, S; Moran, D; Morawski, P; Morello, M J; Mountain, R; Mous, I; Muheim, F; Müller, K; Muresan, R; Muryn, B; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neufeld, N; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nicol, M; Niess, V; Niet, R; Nikitin, N; Nikodem, T; Nomerotski, A; Novoselov, A; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Otalora Goicochea, J M; Owen, P; Oyanguren, A; Pal, B K; Palano, A; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrick, G N; Patrignani, C; Pavel-Nicorescu, C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Perez Trigo, E; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pessina, G; Petridis, K; Petrolini, A; Phan, A; Picatoste Olloqui, E; Pietrzyk, B; Pilař, T; Pinci, D; Playfer, S; Plo Casasus, M; Polci, F; Polok, G; Poluektov, A; Polycarpo, E; Popov, A; Popov, D; Popovici, B; Potterat, C; Powell, A; Prisciandaro, J; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Ricciardi, S; Richards, A; Rinnert, K; Rives Molina, V; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodriguez Perez, P; Roiser, S; Romanovsky, V; Romero Vidal, A; Rouvinet, J; Ruf, T; Ruffini, F; Ruiz, H; Ruiz Valls, P; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salustino Guimaraes, V; Salzmann, C; Sanmartin Sedes, B; Sannino, M; Santacesaria, R; Santamarina Rios, C; Santovetti, E; Sapunov, M; Sarti, A; Satriano, C; Satta, A; Savrie, M; Savrina, D; Schaack, P; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M -H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Senderowska, K; Sepp, I; Serra, N; Serrano, J; Seyfert, P; Shapkin, M; Shapoval, I; Shatalov, P; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, O; Shevchenko, V; Shires, A; Silva Coutinho, R; Skwarnicki, T; Smith, N A; Smith, E; Smith, M; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Stagni, F; Stahl, S; Steinkamp, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Subbiah, V K; Sun, L; Swientek, S; Syropoulos, V; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teklishyn, M; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tresch, M; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Urner, D; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vilasis-Cardona, X; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; Waldi, R; Wallace, R; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Webber, A D; Websdale, D; Whitehead, M; Wicht, J; Wiechczynski, J; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, F; Xing, Z; Yang, Z; Young, R; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L; Zvyagin, A
2013-01-01
Searches for the lepton flavour violating decay $\\tau^-\\to \\mu^-\\mu^+\\mu^-$ and the lepton flavour and baryon number violating decays $\\tau^-\\to \\bar{p}\\mu^+\\mu^-$ and $\\tau^-\\to p\\mu^-\\mu^-$ have been carried out using proton-proton collision data, corresponding to an integrated luminosity of $1.0$ fb$^{-1}$, taken by the LHCb experiment at $\\sqrt{s} = 7$ TeV. No evidence has been found for any signal, and limits have been set at $90\\%$ confidence level on the branching fractions: $\\cal B(\\tau^-\\to \\mu^-\\mu^+\\mu^-) < 8.0 \\times 10^{-8}$, $\\cal B(\\tau^-\\to \\bar{p}\\mu^+\\mu^-) < 3.3 \\times 10^{-7}$ and $\\cal B(\\tau^-\\to p\\mu^-\\mu^-) < 4.4 \\times 10^{-7}$. The results for the $\\tau^-\\to \\bar{p}\\mu^+\\mu^-$ and $\\tau^-\\to p\\mu^-\\mu^-$ decay modes represent the first direct experimental limits on these channels.
International Nuclear Information System (INIS)
Bowes, J.P.; Foot, R.; Volkas, R.R.
1997-01-01
In gauge theories like the standard model, the electric charges of the fermions can be heavily constrained from the classical structure of the theory and from the cancellation of anomalies. There is however mounting evidence suggesting that these anomaly constraints are not as well motivated as the classical constraints. In light of this, possible modifications of the minimal standard model are discussed which will give a complete electric charge quantisation from classical constraints alone. Because these modifications to the Standard Model involve the consideration of baryon number violating scalar interactions, a complete catalogue of the simplest ways to modify the Standard Model is presented so as to introduce explicit baryon number violation. 9 refs., 7 figs
Energy Technology Data Exchange (ETDEWEB)
Bowes, J.P.; Foot, R.; Volkas, R.R.
1997-06-01
In gauge theories like the standard model, the electric charges of the fermions can be heavily constrained from the classical structure of the theory and from the cancellation of anomalies. There is however mounting evidence suggesting that these anomaly constraints are not as well motivated as the classical constraints. In light of this, possible modifications of the minimal standard model are discussed which will give a complete electric charge quantisation from classical constraints alone. Because these modifications to the Standard Model involve the consideration of baryon number violating scalar interactions, a complete catalogue of the simplest ways to modify the Standard Model is presented so as to introduce explicit baryon number violation. 9 refs., 7 figs.
Baryon number generation in a flipped SU(5) x U(1) model
International Nuclear Information System (INIS)
Campbell, B.; Hagelin, J.; Nanopoulos, D.V.; Olive, K.A.
1988-01-01
We consider the possibilities for generating a baryon asymmetry in the early universe in a flipped SU(5) x U(1) model inspired by the superstring. Depending on the temperature of the radiation background after inflation we can distinguish between two scenarios for baryogenesis: (1) After reheating the original SU(5) x U(1) symmetry is restored, or there was no inflation at all; (2) reheating after inflation is rather weak and SU(5) x U(1) is broken. In either case the asymmetry is generated by the out-of-equilibrium decays of a massive SU(3) x SU(2) x U(1) singlet field φ m . In the flipped SU(5) x U(1) model, gauge symmetry breaking is triggered by strong coupling phenomena, and is in general accompanied by the production of entropy. We examine constraints on the reheating temperature and the strong coupling scale in each of the scenarios. (orig.)
Parity-non-conserving nuclear forces
International Nuclear Information System (INIS)
Desplanques, B.
1979-01-01
Theoretical and phenomenological approaches to parity-non-conserving nuclear forces are reviewed. Recent developments in the calculation of weak meson-nucleon coupling constants, whose knowledge is necessary to determine theoretically the parity-non-conserving nucleon-nucleon potential, are described. The consistency of different measurements of parity-non-conserving effects is discussed and the information they provide is compared to theoretical predictions
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
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)
Parity non-conservation in atoms
International Nuclear Information System (INIS)
Barkov, L.M.
1982-01-01
The parity non-conservation discovered in particle physics in 1959 has consequences on the behaviour of atoms illuminated by light of circular polarization. The theoretical treatments of this topic and recent experimental test of detecting the effects of parity non-conservation on atomic physics are listed, reviewed and illustrated. The main experimental results and limits are summarized. Proposed future experiments are discussed. (D.Gy.)
Lepton flavor non-conservation
International Nuclear Information System (INIS)
Kosmas, T.S.; Tuebingen Univ.; Leontaris, G.K.; Vergados, J.D.
1994-01-01
In the present work we review the most prominent lepton flavor violating processes (μ → eγ, μ → 3e, (μ - , e -) conversion, M - M oscillations etc.), in the context of unified gauge theories. Many currently fashionable extensions of the standard model are considered, such as: i) extensions of the fermion sector (right-handed neutrino); ii) minimal extensions involving additional Higgs scalars (more than one isodoublets, singly and doubly charged isosinglets, isotriplets with doubly charged members etc.); iii) supersymmetric or superstring inspired unified models emphasizing the implications of the renormalization group equations in the leptonic sector. Special attention is given to the experimentally most interesting (μ - , e - ) conversion in the presence of nuclei. The relevant nuclear aspects of the amplitudes are discussed in a number of fashionable nuclear models. The main features of the relevant experiments are also discussed, and detailed predictions of the above models are compared to the present experimental limits. (Author)
Flavor and baryon quantum numbers and their nondiffractive renormalizations of the Pomeron
International Nuclear Information System (INIS)
Dash, J.W.; Jones, S.T.; Manesis, E.K.
1978-01-01
We present a theoretical review and a detailed phonomenological description of the ''flavoring'' of the bare Pomeron pole at t = 0 (i.e., the nondiffractive renormalization of its multiperipheral unitarity sum by strange quarks, charmed quarks, diquarks,...) from an ''unflavored'' intercept alpha-circumflex = 0.85 to a ''flavored'' intercept α approx. = 1.08. Experimentally, flavoring effects seem to converge rapidly; hence this number is probably close to the bare intercept of the Reggeon field theory. We treat NN, πN, and KN total cross sections and real to imaginary amplitude ratios. We do not observe oscillations. We pay particular attention to 2sigma/sub K/N - sigma/sub piN/ which rises monotonically. We present a closely related combination of inelastic diffraction cross sections which decreases monotonically, indicating that vacuum amplitudes are not simply the sum of a Pomeron pole and an ideally mixed f. In fact we argue that a Pomeron + f structure is neither compatible with flavoring nor with schemes in which flavoring is somehow absorbed away. In contrast, flavoring is required for consistency with experiment by the Chew-Rosenzweig hypothesis of the Pomeron-f identity. We close with a description of flavoring threshold effects on the Reggeon field theory at current energies
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.
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
International Nuclear Information System (INIS)
Hasegawa, K.; Lim, C.S.; Ogure, K.
2003-01-01
We propose a two-zero-texture general Zee model, compatible with the large mixing angle Mikheyev-Smirnov-Wolfenstein solution. The washing out of the baryon number does not occur in this model for an adequate parameter range. We check the consistency of a model with the constraints coming from flavor changing neutral current processes, the recent cosmic microwave background observation, and the Z-burst scenario
Hasegawa, K.; Lim, C. S.; Ogure, K.
2003-09-01
We propose a two-zero-texture general Zee model, compatible with the large mixing angle Mikheyev-Smirnov-Wolfenstein solution. The washing out of the baryon number does not occur in this model for an adequate parameter range. We check the consistency of a model with the constraints coming from flavor changing neutral current processes, the recent cosmic microwave background observation, and the Z-burst scenario.
Hasegawa, K.; Lim, C. S.; Ogure, K.
2003-01-01
We propose a two-zero-texture general Zee model, compatible with the large mixing angle Mikheyev-Smirnov-Wolfenstein solution. The washing out of the baryon number does not occur in this model for an adequate parameter range. We check the consistency of a model with the constraints coming from flavor changing neutral current processes, the recent cosmic microwave background observation, and the Z-burst scenario.
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)
Axino dark matter and baryon number asymmetry production by the Q-ball decay in gauge mediation
Energy Technology Data Exchange (ETDEWEB)
Kasuya, Shinta [Department of Mathematics and Physics, Kanagawa University, Kanagawa 259-1293 (Japan); Kawakami, Etsuko; Kawasaki, Masahiro, E-mail: kasuya@kanagawa-u.ac.jp, E-mail: kwkm@icrr.u-tokyo.ac.jp, E-mail: kawasaki@icrr.u-tokyo.ac.jp [Institute for Cosmic Ray Research, University of Tokyo, Chiba 277-8582 (Japan)
2016-03-01
We investigate the Q-ball decay into the axino dark matter in the gauge-mediated supersymmetry breaking. In our scenario, the Q ball decays mainly into nucleons and partially into axinos to account respectively for the baryon asymmetry and the dark matter of the universe. The Q ball decays well before the big bang nucleosynthesis so that it is not affected by the decay. We show the region of the parameters which realizes this scenario.
Leptogenesis from R parity non-conservation
Energy Technology Data Exchange (ETDEWEB)
Hambye, T. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Frascati, RM (Italy); Ma, E. [Riverside Univ. of California, Riverside, CA (United States). Dept. of Physics; Sarkar, U. [Physical Research Laboratory, Ahmedabad (India)
2000-07-01
It is known that realistic neutrino masses for neutrino oscillations may be obtained from R parity nonconserving supersymmetry. It is also known that such interactions would erase any preexisting lepton or baryon asymmetry of the Universe because of the inevitable intervention of the electroweak sphalerons. It is showed how a crucial subset of these R parity nonconserving terms may in fact create its own successful leptogenesis.
Leptogenesis from R parity non-conservation
International Nuclear Information System (INIS)
Hambye, T.; Ma, E.
2000-01-01
It is known that realistic neutrino masses for neutrino oscillations may be obtained from R parity nonconserving supersymmetry. It is also known that such interactions would erase any preexisting lepton or baryon asymmetry of the Universe because of the inevitable intervention of the electroweak sphalerons. It is showed how a crucial subset of these R parity nonconserving terms may in fact create its own successful Leptogenesis
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...
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
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.)
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
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)
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.
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
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 ...
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.)
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
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
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.)
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.
Relative Stabilities of Conserved and Non-Conserved Structures in the OB-Fold Superfamily
Directory of Open Access Journals (Sweden)
Andrei T. Alexandrescu
2009-05-01
Full Text Available The OB-fold is a diverse structure superfamily based on a β-barrel motif that is often supplemented with additional non-conserved secondary structures. Previous deletion mutagenesis and NMR hydrogen exchange studies of three OB-fold proteins showed that the structural stabilities of sites within the conserved β-barrels were larger than sites in non-conserved segments. In this work we examined a database of 80 representative domain structures currently classified as OB-folds, to establish the basis of this effect. Residue-specific values were obtained for the number of Cα-Cα distance contacts, sequence hydrophobicities, crystallographic B-factors, and theoretical B-factors calculated from a Gaussian Network Model. All four parameters point to a larger average flexibility for the non-conserved structures compared to the conserved β-barrels. The theoretical B-factors and contact densities show the highest sensitivity.Our results suggest a model of protein structure evolution in which novel structural features develop at the periphery of conserved motifs. Core residues are more resistant to structural changes during evolution since their substitution would disrupt a larger number of interactions. Similar factors are likely to account for the differences in stability to unfolding between conserved and non-conserved structures.
Baryonic and Non-Baryonic Dark Matter
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...
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.
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
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.
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.
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-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
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)
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)
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.
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.
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
Parity non-conserving effects in neutron-nucleus scattering
International Nuclear Information System (INIS)
Desplanques, B.
1990-01-01
The present lecture reviews the motivations which led to study the contribution of the neutron-nucleus component to parity-non-conserving effects observed in medium-heavy nuclei and considers its present status. It is shown that it cannot account for those experimental data. The order interpretation of these effects, which cannot lead to precise statements, is schematically described
Baryons and baryon resonances in nuclear matter
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.
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)
CP violation in the baryon sector
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.
Analysis of Baryon Angular Correlations with Pythia
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.
International Nuclear Information System (INIS)
Gipson, J.M.; Marshak, R.E.
1984-01-01
The supersymmetric versions of the left-right-symmetric SU/sub C/(4) x SU/sub L/(2) x SU/sub R/(2) Pati-Salam theory and the grand unified SO(10) theory are studied. In the minimal versions of these models the requirement of soft or spontaneous breaking of supersymmetry, together with renormalizibility, leads to an accidental global U(1) symmetry which leads to baryon-number conservation. A necessary condition for this symmetry to be broken is the existence of fields which are antisymmetric in at least two SU/sub C/(4) indices. The introduction of such fields may allow for observable neutron oscillation
Study of the baryon-baryon interaction in nucleon-nucleon and pion-deuteron scattering
International Nuclear Information System (INIS)
Fuchs, M.
1993-01-01
After the definition of the Hamiltonian in general form by meson production and absorption the transition to operators pursued, which connect only spaces with definite meson numbers. In this approximation first the self-energy of a single baryon was calculated in its full energy and momentum dependence. Then the formal expressions for the T matrices of nucleon-nucleon and pion-deuteron scattering were derived. The essential components of these expressions are the baryon-baryon T matrix ant transition amplitudes from pion-deuteron channels to baryon-baryon states. The central chapter dealt with the calculation of the baryon-baryon interaction for the general form of the vertices, with the solution of the binding problem and the baryon-baryon T matrix. Finally followed the results on the nucleon-nucleon and pion-deuteron scattering. For this first the transition amplitudes from pion-deuteron states to intermediate baryon-baryon states and the Born graphs of the pion-deuteron scattering had to be calculated. After some remarks to the transition from partial-wave decomposed T matrices to scattering observables an extensive representation of the total, partial, and differential cross sections and a series of spin observables (analyzing powers and spin correlations) for the elastic proton-proton, neutron-proton, and pion-deuteron scattering as well for the fusion reaction pp→πd and the breakup reaction πd→pp follows. Thereby the energies reached from the nucleon-nucleon respectively pion-deuteron threshold up to 100 MeV above the delta resonance
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)
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
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.
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)
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.
An uncertainty inclusive un-mixing model to identify tracer non-conservativeness
Sherriff, Sophie; Rowan, John; Franks, Stewart; Fenton, Owen; Jordan, Phil; hUallacháin, Daire Ó.
2015-04-01
Sediment fingerprinting is being increasingly recognised as an essential tool for catchment soil and water management. Selected physico-chemical properties (tracers) of soils and river sediments are used in a statistically-based 'un-mixing' model to apportion sediment delivered to the catchment outlet (target) to its upstream sediment sources. Development of uncertainty-inclusive approaches, taking into account uncertainties in the sampling, measurement and statistical un-mixing, are improving the robustness of results. However, methodological challenges remain including issues of particle size and organic matter selectivity and non-conservative behaviour of tracers - relating to biogeochemical transformations along the transport pathway. This study builds on our earlier uncertainty-inclusive approach (FR2000) to detect and assess the impact of tracer non-conservativeness using synthetic data before applying these lessons to new field data from Ireland. Un-mixing was conducted on 'pristine' and 'corrupted' synthetic datasets containing three to fifty tracers (in the corrupted dataset one target tracer value was manually corrupted to replicate non-conservative behaviour). Additionally, a smaller corrupted dataset was un-mixed using a permutation version of the algorithm. Field data was collected in an 11 km2 river catchment in Ireland. Source samples were collected from topsoils, subsoils, channel banks, open field drains, damaged road verges and farm tracks. Target samples were collected using time integrated suspended sediment samplers at the catchment outlet at 6-12 week intervals from July 2012 to June 2013. Samples were dried (affected whereas uncertainty was only marginally impacted by the corrupted tracer. Improvement of uncertainty resulted from increasing the number of tracers in both the perfect and corrupted datasets. FR2000 was capable of detecting non-conservative tracer behaviour within the range of mean source values, therefore, it provided a more
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.)
Parity Non-Conservation in Proton-Proton Elastic Scattering
International Nuclear Information System (INIS)
Brown, V.R.; B.F. Gibson; J.A. Carlson; R. Schiavilla
2002-01-01
The parity non-conserving longitudinal asymmetry in proton-proton (pp) elastic scattering is calculated in the lab-energy range 0-350 MeV using contemporary, realistic strong-interaction potentials combined with a weak-interaction potential comprised of rho- and omega-meson exchanges as exemplified by the DDH model. Values for the rho- and omega-meson coupling constants, h rho rho rho and h rho rho omega , are determined from comparison with the measured asymmetries at 13.6 MeV, 45 MeV, and 221 MeV
Helicity non-conserving form factor of the proton
Energy Technology Data Exchange (ETDEWEB)
Voutier, E.; Furget, C.; Knox, S. [Universite Joseph Fourier, Grenoble (France)] [and others
1994-04-01
The study of the hadron structure in the high Q{sup 2} range contributes to the understanding of the mechanisms responsible for the confinement of quarks and gluons. Among the numerous experimental candidates sensitive to these mechanisms, the helicity non-conserving form factor of the proton is a privileged observable since it is controlled by non-perturbative effects. The authors investigate here the feasibility of high Q{sup 2} measurements of this form factor by means of the recoil polarization method in the context of the CEBAF 8 GeV facility. For that purpose, they discuss the development of a high energy proton polarimeter, based on the H({rvec p},pp) elastic scattering, to be placed at the focal plane of a new hadron spectrometer. It is shown that this experimental method significantly improves the knowledge of the helicity non-conserving form factor of the proton up to 10 GeV{sup 2}/c{sup 2}.
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)
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
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
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
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 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.)
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.)
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
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
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)
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.)
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
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
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
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.)
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
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.
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
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
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.
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
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.)
Regulatory interventions necessitated by non-conservative operator decisions
International Nuclear Information System (INIS)
Ojha, D.; Chande, S.K.; Sharma, S.K.
2005-01-01
Presently, India has 15 nuclear power units in operation and 8 units under construction. Though the safety performance of the Nuclear Power Plants (NPPs) in India has been excellent, a few recent events indicate that conservative decision making process can possibly get affected by perceived production goals. In one of the events, a need for some maintenance work arose while reactor start-up was in progress. After it was realized that the maintenance would require considerable time, the proper course of action would have been to shutdown the reactor and add neutron poison to moderator to ensure sufficient sub criticality. This was not done, as it would have delayed the start up of the reactor on completion of maintenance. In another incident, an unintended slow increase in reactor power occurred due to the adjuster rods becoming inoperable on account of blowing-off of fuses in their power supply. Under this condition, the reactor should have been tripped which was not done. Further, the automatic addition of boron poison to the reactor was inhibited. Regulatory review showed that both the incidents were indicative of degradation in safety culture and reflected operator's overriding concern for keeping the units in operation. Appropriate corrective actions were taken to prevent recurrence of such events in the respective units as also in all other operating units of similar type. In the wake of improved production performance operators may develop a tendency to create new operational records and compete with other units. This aspect points out to a need for careful study of events to check the presence of any element of non-conservative decision-making and to identify leading indicators of degradation in safety performance. (author)
Torrico, Jordana; Ohanyan, Vadim; Rojas, Onofre
2018-05-01
We consider the diamond chain with S = 1/2 XYZ vertical dimers which interact with the intermediate sites via the interaction of the Ising type. We also suppose all four spins form the diamond-shaped plaquette to have different g-factors. The non-uniform g-factors within the quantum spin dimer as well as the XY-anisotropy of the exchange interaction lead to the non-conserving magnetization for the chain. We analyze the effects of non-conserving magnetization as well as the effects of the appearance of negative g-factors among the spins from the unit cell. A number of unusual frustrated states for ferromagnetic couplings and g-factors with non-uniform signs are found out. These frustrated states generalize the "half-fire-half-ice" state introduced in reference Yin et al. (2015). The corresponding zero-temperature ground state phase diagrams are presented.
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
Baryon symmetric big bang cosmology
Stecker, F. W.
1978-01-01
Both the quantum theory and Einsteins theory of special relativity lead to the supposition that matter and antimatter were produced in equal quantities during the big bang. It is noted that local matter/antimatter asymmetries may be reconciled with universal symmetry by assuming (1) a slight imbalance of matter over antimatter in the early universe, annihilation, and a subsequent remainder of matter; (2) localized regions of excess for one or the other type of matter as an initial condition; and (3) an extremely dense, high temperature state with zero net baryon number; i.e., matter/antimatter symmetry. Attention is given to the third assumption, which is the simplest and the most in keeping with current knowledge of the cosmos, especially as pertains the universality of 3 K background radiation. Mechanisms of galaxy formation are discussed, whereby matter and antimatter might have collided and annihilated each other, or have coexisted (and continue to coexist) at vast distances. It is pointed out that baryon symmetric big bang cosmology could probably be proved if an antinucleus could be detected in cosmic radiation.
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.
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
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.
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.
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.)
Energy Technology Data Exchange (ETDEWEB)
Brochu, F
2000-04-01
This thesis is based on baryon number and then R-Parity (R{sub p}) violation, both allowed in the Minimal Supersymmetric Standard Model (MSSM) framework. This hypothesis leads to supersymmetric particles' decay topologies significantly different from those ever studied and opens new possibilities on searches for supersymmetry. We will detail throughout this work the phenomenological consequences of the baryon number violation hypothesis, the resulting decay signatures in an e{sup +}e{sup -} collider and the analysis setup developed to isolate these decays in the data collected by the L3 experiment at LEP between 1997 and 2000. In order to validate the search methods developed, we also measured the cross-section of the process e{sup +}e{sup -} {yields} ZZ {yields} qq-bar q'q'-bar. (author)
Transition mixing among baryons
International Nuclear Information System (INIS)
Faiman, D.
1976-01-01
A degenerate perturbation theory model for mass splitting within the 70,1 - baryon multiplet is proposed. It is found that dominance of the lowest-lying two-body 56x35 intermediate states produces mixing angles in fair approximation to those previously deduced from SU(6)sub(W) analysis of decay data. The prediction of the couplings of all hitherto undetected members of the multiplet and of mass were made. The results call into question the nature of Λ (1405). (author)
International Nuclear Information System (INIS)
Uschersohn, J.; Elbaz, E.
1983-01-01
In the rishon model the leptons and the quarks can be classified in either doublets or quadruplets of a SU(2) group. Gauge invariance leads to different charged current interactions in the doublet and the quadruplet cases. Demanding that the neutral currents be the same in the two cases, one obtains relations between the different charged current couplings to leptons and quark; moreover, if these transform as linear combinations of doublets and quadruplets, one can estimate the mass of the gauge boson responsible for baryon decay to be not larger than 10 5 GeV. A SU(2)sub(L) x U(1) model is treated in detail
Energy Technology Data Exchange (ETDEWEB)
Comyn, Martin
1992-07-01
The unique opportunities for the study of baryon spectroscopy at the TRIUMF KAON Factory are outlined. Related issues in other areas of hadron spectroscopy are discussed. The complex of accelerators that comprise the TRIUMF KAON Factory, and the properties of the separated beams that will be available to experimenters, are described. Initial design considerations for detectors to be used in the study of hadron spectroscopy are presented, along with a proposed detector configuration. The progress towards realization of the TRIUMF KAON Factory is examined, and the timetable for the determination of the initial experimental programme and facilities is explained. 23 refs., 4 figs., 5 tabs.
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
Compressed Baryonic Matter of Astrophysics
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
Parity non-conserving effects in thermal neutron-deuteron radiative capture
International Nuclear Information System (INIS)
Desplanques, B.
1985-01-01
Predictions of parity non-conserving effects in thermal neutron-deuteron radiative capture are presented. The sensitivity of the results to models of the strong interaction as well as the validity of approximations made in previous calculations are discussed
An analytical model for non-conservative pollutants mixing in the surf zone.
Ki, Seo Jin; Hwang, Jin Hwan; Kang, Joo-Hyon; Kim, Joon Ha
2009-01-01
Accurate simulation of the surf zone is a prerequisite to improve beach management as well as to understand the fundamentals of fate and transport of contaminants. In the present study, a diagnostic model modified from a classic solute model is provided to illuminate non-conservative pollutants behavior in the surf zone. To readily understand controlling processes in the surf zone, a new dimensionless quantity is employed with index of kappa number (K, a ratio of inactivation rate to transport rate of microbial pollutant in the surf zone), which was then evaluated under different environmental frames during a week simulation period. The sensitivity analysis showed that hydrodynamics and concentration gradients in the surf zone mostly depend on n (number of rip currents), indicating that n should be carefully adjusted in the model. The simulation results reveal, furthermore, that large deviation typically occurs in the daytime, signifying inactivation of fecal indicator bacteria is the main process to control surf zone water quality during the day. Overall, the analytical model shows a good agreement between predicted and synthetic data (R(2) = 0.51 and 0.67 for FC and ENT, respectively) for the simulated period, amplifying its potential use in the surf zone modelling. It is recommended that when the dimensionless index is much larger than 0.5, the present modified model can predict better than the conventional model, but if index is smaller than 0.5, the conventional model is more efficient with respect to time and cost.
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
Electromagnetic properties of baryons
Energy Technology Data Exchange (ETDEWEB)
Haupt, C.
2006-07-01
Static observables of bound state systems in field theoretic descriptions are usually extracted from form factors in the limit of vanishing squared four-momentum transfer of the probing exchange particle. On the other hand, static properties in nonrelativistic quantum mechanics can be formulated by means of expectation values involving essentially scalar products of wave functions. The main objective of this work is to show that a synthesis of both approaches is indeed possible - at least if certain restrictions are made to the kind of interactions between the constituents of the bound system - leading to new insights into the structure of static properties. The focus lies especially on the charge radii and magnetic moments of baryons described within a covariant constituent quark model having its field theoretic foundations in the Bethe-Salpeter equation. The current matrix element in the Breit frame between the vertex functions is derived. The charge radius and magnetic moment of a bound three-fermion system is then derived by starting from their usual definition from form factors and in case of the charge radius also from the well-known radius of a charge distribution in classical electrodynamics. In both cases the static limit at the photon point is taken analytically and subsequently the integration over the relative energy variables is done. Finally the vertex functions are replaced by Salpeter amplitudes and the expression is symmetrized over the three fermions. The final results express the charge radius and magnetic moment of the three-fermion system as expectation values with respect to Salpeter amplitudes. The numerical implementation of the analytic results is done within a covariant constituent quark model with quark confinement and a residual instanton interaction accounting for the fine structure of the observed mass spectra. The Salpeter amplitudes which where obtained by solving the Salpeter equation are used to compute the expectation values of
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 .
Speeding up Monte Carlo molecular simulation by a non-conservative early rejection scheme
Kadoura, Ahmad Salim
2015-04-23
Monte Carlo (MC) molecular simulation describes fluid systems with rich information, and it is capable of predicting many fluid properties of engineering interest. In general, it is more accurate and representative than equations of state. On the other hand, it requires much more computational effort and simulation time. For that purpose, several techniques have been developed in order to speed up MC molecular simulations while preserving their precision. In particular, early rejection schemes are capable of reducing computational cost by reaching the rejection decision for the undesired MC trials at an earlier stage in comparison to the conventional scheme. In a recent work, we have introduced a ‘conservative’ early rejection scheme as a method to accelerate MC simulations while producing exactly the same results as the conventional algorithm. In this paper, we introduce a ‘non-conservative’ early rejection scheme, which is much faster than the conservative scheme, yet it preserves the precision of the method. The proposed scheme is tested for systems of structureless Lennard-Jones particles in both canonical and NVT-Gibbs ensembles. Numerical experiments were conducted at several thermodynamic conditions for different number of particles. Results show that at certain thermodynamic conditions, the non-conservative method is capable of doubling the speed of the MC molecular simulations in both canonical and NVT-Gibbs ensembles. © 2015 Taylor & Francis
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
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)
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
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.
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
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.)
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”.
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.)
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.
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.
Weak coupling large-N transitions at finite baryon density
Hollowood, Timothy J.; Kumar, S. Prem; Myers, Joyce C.
We study thermodynamics of free SU(N) gauge theory with a large number of colours and flavours on a three-sphere, in the presence of a baryon number chemical potential. Reducing the system to a holomorphic large-N matrix integral, paying specific attention to theories with scalar flavours (squarks),
Energy and angular-momentum non-conservation in four-dimensional gauge theories
International Nuclear Information System (INIS)
Manohar, A.
1985-01-01
We study energy and angular-momentum non-conservation on four-dimensional chiral gauge theories using Landau levels. These effects are physical manifestations of the usual gauge anomaly, and enable us to understand in a semi-classical approximation why anomaly cancellation is required for a consistent field theory. (orig.)
Prospects for Parity Non-conservation Experiments with Highly Charged Heavy Ions
Maul, M.; Schäfer, A.; Greiner, W.; Indelicato, P.
1996-01-01
We discuss the prospects for parity non-conservation experiments with highly charged heavy ions. Energy levels and parity mixing for heavy ions with two to five electrons are calculated. We investigate two-photon-transitions and the possibility to observe interference effects between weak-matrix elements and Stark matrix elements for periodic electric field configurations.
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
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
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
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.)
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
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.)
Multistrange Meson-Baryon Dynamics and Resonance Generation
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.
Baryon symmetric big-bang cosmology. [matter-antimatter symmetry
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.
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.
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
Energy Technology Data Exchange (ETDEWEB)
Gandelman, Miriam Mendes
1992-07-01
In this work the A dependence of the {lambda} and {lambda}{sup -} production cross sections is studied using the E769 data for the 250 GeV/c{pi}{sup -} beam interacting on Be, Cu, Al and W targets. The measured mean value of {alpha} in the region - 0.2 < x{sub f} < 0.3 and p{sub t} < 2 GeV/c is 1.03 {+-} 0.02 for the {lambda} baryon and 1.01 {+-} 0.02 for the {lambda}{sup -}. No difference is measured between the values of {alpha} for {lambda} and {lambda}{sup -}: {alpha} is a global decreasing function of x{sub f} and has no significant variation with p{sub t}. (author). 31 refs, 48 figs, 16 tabs.
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)
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.)
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.
Charmed baryonic resonances in medium
Directory of Open Access Journals (Sweden)
Tolos Laura
2015-01-01
Full Text Available We discuss the behavior of dynamically-generated charmed baryonic resonances in matter within a unitarized coupled-channel model consistent with heavy-quark spin symmetry. We analyze the implications for the formation of D-meson bound states in nuclei and the propagation of D mesons in heavy-ion collisions from RHIC to FAIR energies.
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.
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
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
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)
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
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 .
Development of Non-Conservative Joints in Beam Networks for Vibration Energy Flow Analysis
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Jee-Hun Song
2007-01-01
Full Text Available Our work aims to find a general solution for the vibrational energy flow through a plane network of beams on the basis of an energy flow analysis. A joint between two semi-infinite beams are modeled by three sets of springs and dashpots. Thus, the results can incorporate the case of complaint and non-conservative in all the three degrees of freedom. In the cases of finite coupled structures connected at a certain angle, the derived non-conservative joints and developed wave energy equation were applied. The joint properties, the frequency, the coupling angle, and the internal loss factor were changed to evaluate the proposed methods for predicting medium-to-high frequency vibrational energy and intensity distributions.
Application of the HN method to radiative heat transfer for a non-conservative slab
International Nuclear Information System (INIS)
Bulut, S.; Guelecyuez, M.C.
2008-01-01
The H N method is used to calculate the partial fluxes relevant to radiative transfer in a plane parallel medium for linearly anisotropic scattering with specularly and diffusely reflecting boundaries. The solutions are obtained for the non-conservative case. The numerical values of the heat flux functions at the boundaries of the medium are calculated for the two source functions. The numerical results and the convergence of the H N method are compared with earlier results. (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
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.)
Neutrino number of the universe
International Nuclear Information System (INIS)
Kolb, E.W.
1981-01-01
The influence of grand unified theories on the lepton number of the universe is reviewed. A scenario is presented for the generation of a large (>> 1) lepton number and a small (<< 1) baryon number. 15 references
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.
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.
Dark and visible matter in a baryon-symmetric universe via the Affleck-Dine mechanism
International Nuclear Information System (INIS)
Bell, Nicole F.; Petraki, Kalliopi; Volkas, Raymond R.; Shoemaker, Ian M.
2011-01-01
The similarity of the visible and dark matter abundances indicates that they may originate via the same mechanism. If both the dark and visible matter are charged under a generalized baryon number, then the asymmetry of the visible sector may be compensated by an asymmetry in the dark sector. We show how the separation of the baryonic and the -antibaryonic charge can originate in the vacuum, via the Affleck-Dine mechanism, due to the breaking of a symmetry orthogonal to the baryon number. Symmetry restoration in the current epoch guarantees the individual stability of the two sectors.
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)
Baryon physics in holographic QCD
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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%.
Moduli induced cogenesis of baryon asymmetry and dark matter
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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.
International Nuclear Information System (INIS)
Biro, T.S.; Zimanyi, J.
1993-06-01
A heavy bottom-charm six-quark baryon is considered. A semiclassical and a Gaussian estimate show that the octet-octet bbb-ccc configuration can be favoured energetically rather than the singlet-singlet one. This result suggests that a confined bbb-ccc six-quark state may exist. Such objects may be produced in suitable amounts by heavy-ion collisions at Large Hadronic Collider energies. (R.P.) 8 refs. 1 fig
The Compressed Baryonic Matter experiment
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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.
Sum rules, asymptotic behaviour and (multi)baryon states in the Skyrme model
International Nuclear Information System (INIS)
Mignaco, J.A.; Wulck, S.
1990-01-01
We obtain sum roles that should be satisfied by the solutions of the Euler-Lagrange equation for the chiral angle in the Skyrme model in the hedgehog representation. The sum rules allow to determine the existence of solutions with integer baryon number for well determined values of a relevant dimensionless parameter Φ only. For all other values, there are no solutions with integer baryon number, in particular for the pure non-linear sigma model. (author)
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)
Constraints of a parity-conserving/time-reversal-non-conserving interaction
International Nuclear Information System (INIS)
Oers, Willem T.H. van
2002-01-01
Time-Reversal-Invariance non-conservation has for the first time been unequivocally demonstrated in a direct measurement at CPLEAR. One then can ask the question: What about tests of time-reversal-invariance in systems other than the kaon system? Tests of time-reversal-invariance can be distinguished as belonging to two classes: the first one deals with time-reversal-invariance-non-conserving (T-odd)/parity violating (P-odd) interactions, while the second one deals with T-odd/P-even interactions (assuming CPT conservation this implies C-conjugation non-conservation). Limits on a T-odd/P-odd interaction follow from measurements of the electric dipole moment of the neutron ( -26 e.cm [95% C.L.]). It provides a limit on a T-odd/P-odd pion-nucleon coupling constant which is less than 10 -4 times the weak interaction strength. Experimental limits on a T-odd/P-even interaction are much less stringent. Following the standard approach of describing the nucleon-nucleon interaction in terms of meson exchanges, it can be shown that only charged ρ-meson exchange and A 1 -meson exchange can lead to a T-odd/P-even interaction. The better constraints stem from measurements of the electric dipole moment of the neutron and from measurements of charge-symmetry breaking in neutron-proton elastic scattering. The latter experiments were executed at TRIUMF (497 and 347 MeV) and at IUCF (183 MeV). All other experiments, like detailed balance experiments, polarization - analyzing power difference determinations, and five-fold correlation experiments with polarized incident nucleons and aligned nuclear targets, have been shown to be at least an order to magnitude less sensitive. Is there room for further experimentation?
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.)
Avoidance of singularity and global non-conservation of energy in general relativity
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Verma, M.M.
2009-06-01
We show that the singularity in the General Theory of Relativity (GTR) is the expression of a non-Machian feature. It can be avoided with a scale-invariant dynamical theory, a property lacking in GTR. It is further argued that the global non-conservation of energy in GTR also results from the lack of scale-invariance, and the field formulation presented by several authors can only partly resolve the problem. Assuming the global energy conservation, we propose a negative energy density component with a positive equation of state that can drive the late-time acceleration in the universe, while the positive component confines to smaller scales. (author)
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
Baryon non-invariant couplings in Higgs effective field theory
International Nuclear Information System (INIS)
Merlo, Luca; Saa, Sara; Sacristan-Barbero, Mario
2017-01-01
The basis of leading operators which are not invariant under baryon number is constructed within the Higgs effective field theory. This list contains 12 dimension six operators, which preserve the combination B - L, to be compared to only 6 operators for the standard model effective field theory. The discussion of the independent flavour contractions is presented in detail for a generic number of fermion families adopting the Hilbert series technique. (orig.)
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
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)
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
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)
Quantum Operator Design for Lattice Baryon Spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Lichtl, Adam [Carnegie Mellon Univ., Pittsburgh, PA (United States)
2006-09-07
A previously-proposed method of constructing spatially-extended gauge-invariant three-quark operators for use in Monte Carlo lattice QCD calculations is tested, and a methodology for using these operators to extract the energies of a large number of baryon states is developed. This work is part of a long-term project undertaken by the Lattice Hadron Physics Collaboration to carry out a first-principles calculation of the low-lying spectrum of QCD. The operators are assemblages of smeared and gauge-covariantly-displaced quark fields having a definite flavor structure. The importance of using smeared fields is dramatically demonstrated. It is found that quark field smearing greatly reduces the couplings to the unwanted high-lying short-wavelength modes, while gauge field smearing drastically reduces the statistical noise in the extended operators.
Σ--antihyperon correlations in Z0 decay and investigation of the baryon production mechanism
International Nuclear Information System (INIS)
Abbiendi, G.; Braibant, S.; Capiluppi, P.; Ciocca, C.; Cuffiani, M.; Dallavalle, M.; Fabbri, F.; Giacomelli, G.; Giacomelli, P.; Ludwig, J.; Merritt, F.S.; Rembser, C.; Ainsley, C.; Batley, R.J.; Carter, J.R.; Hill, J.C.; Tarem, S.; Verzocchi, M.; Voss, H.; Aakesson, P.F.; Barberio, E.; Burckhart, H.J.; Roeck, A. de; Wolf, E.A. de; Ferrari, P.; Frey, A.; Gruwe, M.; Hauschild, M.; Hawkings, R.; Maettig, P.; Nanjo, H.; Pater, J.R.; Pinfold, J.; Pooth, O.; Przybycien, M.; Runge, K.; Sarkisyan, E.K.G.; Schaile, O.; Scharff-Hansen, P.; Schroeder, M.; Shen, B.C.; Strom, D.; Thomson, M.A.; Vannerem, P.; Vertesi, R.; Watkins, P.M.; Watson, A.T.; Alexander, G.; Bella, G.; Etzion, E.; Grunhaus, J.; Toya, D.; Anagnostou, G.; Bell, P.J.; Charlton, D.G.; Hawkes, C.M.; Jeremie, H.; Nakamura, I.; Trigger, I.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Wermes, N.; Anderson, K.J.; Gupta, A.; McPherson, R.A.; Neal, H.A.; Pahl, C.; Smith, A.M.; Stroehmer, R.; Asai, S.; Igo-Kemenes, P.; Junk, T.R.; Karlen, D.; Kawagoe, K.; Kluth, S.; Kobel, M.; Marcellini, S.; Mes, H.; Mikenberg, G.; Mori, T.; Mutter, A.; O'Neale, S.W.; Rozen, Y.; Teuscher, R.; Trocsanyi, Z.; Wilson, J.A.; Axen, D.; Lloyd, S.L.; Martin, A.J.; Bailey, I.; Kanzaki, J.; Kawamoto, T.; Mashimo, T.; Rabbertz, K.; Sherwood, P.; Barillari, T.; Bethke, S.; Kennedy, B.W.; Oh, A.; Plane, D.E.; Schaile, A.D.; Barlow, R.J.; Duerdoth, I.P.; Ford, M.; Kupper, M.; Lillich, J.; Orito, S.; Skuja, A.; Wengler, T.; Wilson, G.W.; Bechtle, P.; Behnke, T.; Desch, K.; Hamann, M.; Heuer, R.D.; Komamiya, S.; Krogh, J. von; McKenna, J.; Menges, W.; Bell, K.W.; Brown, R.M.; Kellogg, R.G.; Bellerive, A.; Carnegie, R.K.; Jovanovic, P.; Krasznahorkay, A.; Meijers, F.; Rossi, A.M.; Benelli, G.; Campana, S.; Gary, J.W.; Giunta, M.; Hanson, G.G.; Oreglia, M.J.; Schumacher, M.; Wolf, G.; Biebel, O.; Boutemeur, M.; Dubbert, J.; Duckeck, G.; Fiedler, F.; Sachs, K.; Saeki, T.; Spano, F.; Turner-Watson, M.F.; Boeriu, O.; Fleck, I.; Herten, G.; Letts, J.; Lu, J.; Mihara, S.; Miller, D.J.; Roney, J.M.; Ueda, I.; Bock, P.; Krieger, P.; Wells, P.S.; Carter, A.A.; Levinson, L.; Mader, W.; Mohr, W.; Chang, C.Y.; Keeler, R.K.; Shears, T.G.; Vollmer, C.F.; Csilling, A.; Hajdu, C.; Horvath, D.; Dado, S.; Goldberg, J.; Harel, A.; Lafferty, G.D.; Renkel, P.; Stahl, A.; Wyatt, T.R.; Dienes, B.; Kraemer, T.; Torrence, E.; Tsur, E.; Ujvari, B.; Duchovni, E.; Gross, E.; Kuhl, T.; Lanske, D.; Lellouch, D.; Meyer, N.; Quadt, A.; Wetterling, D.; Gagnon, P.; Geich-Gimbel, C.; Kobayashi, T.; Loebinger, F.K.; Ludwig, A.; Schieck, J.; Watson, N.K.; Ishii, K.; Landsman, H.; Pilcher, J.E.; Schoerner-Sadenius, T.; Sobie, R.; Michelini, A.; Seuster, R.; Nagai, K.; Pasztor, G.; Soeldner-Rembold, S.; Tasevsky, M.
2009-01-01
Data collected around √(s)=91 GeV by the OPAL experiment at the LEP e + e - collider are used to study the mechanism of baryon formation. As the signature, the fraction of Σ - hyperons whose baryon number is compensated by the production of a anti Σ - , anti Λ or anti Ξ - antihyperon is determined. The method relies entirely on quantum number correlations of the baryons, and not rapidity correlations, making it more model independent than previous studies. Within the context of the JETSET implementation of the string hadronization model, the diquark baryon production model without the popcorn mechanism is strongly disfavored with a significance of 3.8 standard deviations including systematic uncertainties. It is shown that previous studies of the popcorn mechanism with Λanti Λ and p anti p correlations are not conclusive, if parameter uncertainties are considered. (orig.)
International Nuclear Information System (INIS)
Balatz, M.Ya.; Belyaev, I.M.; Dorofeev, V.A.
1993-01-01
In the experiments at the SPHINX facility in the 70 GeV proton beam of the IHEP accelerator the diffractive production reactions p + N → [Σ(1385) 0 K + ] + N and p + N → [Σ(1385) 0 K + ] + N + (neutral particles) were studied. In the effective mass spectra of the [Σ(1385) 0 K + ] system in these processes there were no signals from the anomalously narrow baryon state N φ (1960), which had been observed earlier in the measurement at the BIS-2 setup. 6 refs., 7 figs
International Nuclear Information System (INIS)
Balatz, M.Ya.; Belyaev, I.M.; Dorofeev, V.A.; Dzubenko, G.B.; Filimonov, I.M.; Frolov, S.V.; Golovkin, S.V.; Grishkin, Yu.L.; Gritzuk, M.V.; Kamenskii, A.D.; Kliger, G.K.; Kolganov, V.Z.; Konstantinov, A.S.; Korchagin, Yu.V.; Kozevnikov, A.P.; Kubarovskii, V.P.; Kulman, N.Yu.; Kulyavtsev, A.I.; Kurshetsov, V.F.; Kushnirenko, A.E.; Lakaev, V.S.; Landsberg, L.G.; Lomkatzi, G.S.; Molchanov, V.V.; Mukhin, V.A.; Nilov, A.P.; Novoghilov, Yu.B.; Prutskoi, V.A.; Sitnikov, A.I.; Smolyankin, V.T.; Solyanik, V.I.; Vavilov, D.V.; Victorov, V.A.; Vishnyakov, V.E.
1994-01-01
In the experiments at the SPHINX facility in the 70 GeV proton beam of the IHEP accelerator the diffractive production reactions p+N→[Σ(1385) 0 K + ]+N and p+N→[Σ(1385) 0 K + ]+N+ (neutral particles) were studied. In the effective mass spectra of the [Σ(1385) 0 K + ] system in these processes there were no signals from the anomalously narrow baryon state N φ (1960) which had been observed earlier in the measurement at the BIS-2 setup. (orig.)
Gluon field distribution in baryons
International Nuclear Information System (INIS)
Bissey, F.; Cao, F-G.; Kitson, A.; Lasscock, B.G.; Leinweber, D.B.; Signal, A.I.; Williams, A.G.; Zanotti, J.M.
2005-01-01
Methods for revealing the distribution of gluon fields within the three-quark static-baryon potential are presented. In particular, we outline methods for studying the sensitivity of the source on the emerging vacuum response for the three-quark system. At the same time, we explore the possibility of revealing gluon-field distributions in three-quark systems in QCD without the use of gauge-dependent smoothing techniques. Renderings of flux tubes from a preliminary high-statistics study on a 12 3 x 24 lattice are presented
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 ...
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.
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
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.)
Baryon bags in strong coupling QCD
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.
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.)
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
Strange baryon production in Z hadronic decays
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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.
Search for exotic baryon states with the SPHINX detector
International Nuclear Information System (INIS)
Kurshetsov, V.F.; Landsberg, L.G.
1994-01-01
A number of diffractive processes involving the production of baryon states are studied in a series of experiments using the SPHINX detector and the E p = 70 GeV proton beam of the IHEP accelerator. These include p + N → [pK + K - ] + N, p + N → [pφ] + N, p + N → [Λ(1520)K + ] + N, p + N → [Σ(1385) 0 K + ] + N, p + N → [Σ(1385) 0 K + ] + N + (neutrals), p + N → [Σ 0 K + ] + N, and a number of other transitions. Searches for narrow heavy baryons, which are candidates for cryptoexotic hadron states with hidden strangeness, are reported. The first results on meson production in the deep fragmentation region are presented. 21 refs., 14 figs., 2 tabs
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)
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
Baryons as solitonic solutions of the chiral sigma model
International Nuclear Information System (INIS)
Bentz, W.; Hartmann, J.; Beck, F.
1996-01-01
Self-consistent solitonic solutions with baryon number one are obtained in the chiral quark sigma model. The translational invariant vacuum is stabilized by a Landau ghost subtraction procedure based on the requirement of the Kaellacute en-Lehmann (KL) representation for the meson propagators. The connection of this ghost free model (KL model) to the more popular Nambu-Jona-Lasinio (NJL) model is discussed in detail. copyright 1996 The American Physical Society
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
A Baryonic Solution to the Missing Satellites Problem
Energy Technology Data Exchange (ETDEWEB)
Brooks, Alyson M.; Kuhlen, Michael; Zolotov, Adi; Hooper, Dan
2013-03-01
It has been demonstrated that the inclusion of baryonic physics can alter the dark matter densities in the centers of low-mass galaxies, making the central dark matter slope more shallow than predicted in pure cold dark matter simulations. This flattening of the dark matter profile can occur in the most luminous subhalos around Milky Way mass galaxies. Zolotov et al. have suggested a correction to be applied to the central masses of dark matter-only satellites in order to mimic the affect of (1) the flattening of the dark matter cusp due to supernova feedback in luminous satellites and (2) enhanced tidal stripping due to the presence of a baryonic disk. In this paper, we apply this correction to the z = 0 subhalo masses from the high resolution, dark matter-only Via Lactea II (VL2) simulation, and find that the number of massive subhalos is dramatically reduced. After adopting a stellar mass to halo mass relationship for the VL2 halos, and identifying subhalos that are (1) likely to be destroyed by stripping and (2) likely to have star formation suppressed by photo-heating, we find that the number of massive, luminous satellites around a Milky Way mass galaxy is in agreement with the number of observed satellites around the Milky Way or M31. We conclude that baryonic processes have the potential to solve the missing satellites problem
A measurement of the semileptonic branching ratio BR(b-baryon $\\rightarrow p l\\overline{\
Barate, R; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Pietrzyk, B; Boix, G; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Graugès-Pous, E; Juste, A; Martínez, M; Merino, G; Miquel, R; Mir, L M; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Alemany, R; Becker, U; Bright-Thomas, P G; Casper, David William; Cattaneo, M; Cerutti, F; Ciulli, V; Dissertori, G; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Hansen, J B; Harvey, J; Janot, P; Jost, B; Lehraus, Ivan; Mato, P; Minten, Adolf G; Moneta, L; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rolandi, Luigi; Rousseau, D; Schlatter, W D; Schmitt, M; Schneider, O; Tejessy, W; Teubert, F; Tomalin, I R; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Badaud, F; Chazelle, G; Deschamps, O; Falvard, A; Ferdi, C; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Fearnley, Tom; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Boccali, T; Focardi, E; Parrini, G; Zachariadou, K; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Lynch, J G; Negus, P; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; Buchmüller, O L; Dhamotharan, S; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Girone, M; Goodsir, S M; Martin, E B; Moutoussi, A; Nash, J; Sedgbeer, J K; Spagnolo, P; Williams, M D; Ghete, V M; Girtler, P; Kneringer, E; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Buck, P G; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Williams, M I; Giehl, I; Greene, A M; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Carr, J; Coyle, P; Diaconu, C A; Etienne, F; Leroy, O; Motsch, F; Payre, P; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Antonelli, M; Ragusa, F; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Mannert, C; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Schune, M H; Tournefier, E; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Rizzo, G; Sanguinetti, G; Sciabà, A; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Venturi, A; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Konstantinidis, N P; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Brew, C A J; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Reeve, J; Thompson, L F; Affholderbach, K; Böhrer, A; Brandt, S; Cowan, G D; Grupen, Claus; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Charles, E; Elmer, P; Ferguson, D P S; Gao, Y; González, S; Greening, T C; Hayes, O J; Hu, H; Jin, S; McNamara, P A; Nachtman, J M; Nielsen, J; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zobernig, G
1998-01-01
Inclusive pi^+/-, K^+/- (p,pbar) production is investigated using data recorded by the ALEPH detector between 1992 and 1994. The momentum spectra and multiplicities are measured separately in Z -->bbar, Z-->ccbar and Z-->uubar,ddbar,ssbar decays. The number of protons found in b-hadron decays is used to estimate the fraction of b-baryons in b-events to be (10.2 +/- 0.7 +/- 2.7)%. From an additional study of proton-lepton correlations in b events the branching ratio Br(b-baryon --> plnuX) = (4.63 +/- 0.72 +/- 0.98)% is obtained. The ratio Br(b-baryon --> plnuX)/ Br(b-baryon --> pX) is found to be 0.080 +/- 0.012 +/- 0.014.
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
Baryon decay: Flipped SU(5) surmounts another challenge
Energy Technology Data Exchange (ETDEWEB)
Ellis, J. (European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.); Lopez, J.L.; Nanopoulos, D.V. (Texas A and M Univ., College Station, TX (USA). Center for Theoretical Physics Houston Advanced Research Center (HARC), Woodlands, TX (USA). Astroparticle Physics Group)
1990-12-06
Effective four-dimensional field theories derived from string theories may contain superpotential terms that violate baryon number. Terms that are cubic in the standard model particles are well known to lead to excessively rapid proton decay, and the same is true for terms that are quartic in these light fields. This holds even if the terms contain many powers of fields with large intermediate vacuum expectation values, corresponding to asymmetric manifolds of compactification. We show that no such B-violating superpotential interaction arises in flipped SU(5), thanks to an extra symmetry of the effective cubic d=4 and quartic d=5 superpotentials terms, induced at short distances. We conclude that in this model baryon decay proceeds predominantly through conventional d=6 gauge boson exchange, and we recalculate its rate using the latest LEP data to estimate the heavy gauge boson masses. (orig.).
QCD at Zero Baryon Density and the Polyakov Loop Paradox
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...
Weak decays of doubly heavy baryons. SU(3) analysis
Energy Technology Data Exchange (ETDEWEB)
Wang, Wei; Xing, Zhi-Peng; Xu, Ji [Shanghai Jiao Tong University, INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, School of Physics and Astronomy, Shanghai (China)
2017-11-15
Motivated by the recent LHCb observation of doubly charmed baryon Ξ{sub cc}{sup ++} in the Λ{sub c}{sup +}K{sup -}π{sup +}π{sup +} final state, we analyze the weak decays of doubly heavy baryons Ξ{sub cc}, Ω{sub cc}, Ξ{sub bc}, Ω{sub bc}, Ξ{sub bb} and Ω{sub bb} under the flavor SU(3) symmetry. The decay amplitudes for various semileptonic and nonleptonic decays are parametrized in terms of a few SU(3) irreducible amplitudes. We find a number of relations or sum rules between decay widths and CP asymmetries, which can be examined in future measurements at experimental facilities like LHC, Belle II and CEPC. Moreover, once a few decay branching fractions have been measured in the future, some of these relations may provide hints for exploration of new decay modes. (orig.)
CP violation in multibody decays of beauty baryons
Energy Technology Data Exchange (ETDEWEB)
Durieux, Gauthier
2016-08-15
Beauty baryons are being observed in large numbers in the LHCb detector. The rich kinematic distributions of their multibody decays are therefore becoming accessible and provide us with new opportunities to search for CP violation. We analyse the angular distributions of some three- and four-body decays of spin-1/2 baryons using the Jacob-Wick helicity formalism. The asymmetries that provide access to small differences of CP-odd phases between decay amplitudes of identical CP-even phases are notably discussed. The understanding gained on processes featuring specific resonant intermediate states allows us to establish which asymmetries are relevant for what purpose. It is for instance shown that some CP-odd angular asymmetries measured by the LHCb collaboration in the Λ{sub b}→Λφ→pπ K{sup +}K{sup -} decay are expected to vanish identically.
Baryon-Baryon Interactions ---Nijmegen Extended-Soft-Core Models---
Rijken, T. A.; Nagels, M. M.; Yamamoto, Y.
We review the Nijmegen extended-soft-core (ESC) models for the baryon-baryon (BB) interactions of the SU(3) flavor-octet of baryons (N, Lambda, Sigma, and Xi). The interactions are basically studied from the meson-exchange point of view, in the spirit of the Yukawa-approach to the nuclear force problem [H. Yukawa, ``On the interaction of Elementary Particles I'', Proceedings of the Physico-Mathematical Society of Japan 17 (1935), 48], using generalized soft-core Yukawa-functions. These interactions are supplemented with (i) multiple-gluon-exchange, and (ii) structural effects due to the quark-core of the baryons. We present in some detail the most recent extended-soft-core model, henceforth referred to as ESC08, which is the most complete, sophisticated, and successful interaction-model. Furthermore, we discuss briefly its predecessor the ESC04-model [Th. A. Rijken and Y. Yamamoto, Phys. Rev. C 73 (2006), 044007; Th. A. Rijken and Y. Yamamoto, Ph ys. Rev. C 73 (2006), 044008; Th. A. Rijken and Y. Yamamoto, nucl-th/0608074]. For the soft-core one-boson-exchange (OBE) models we refer to the literature [Th. A. Rijken, in Proceedings of the International Conference on Few-Body Problems in Nuclear and Particle Physics, Quebec, 1974, ed. R. J. Slobodrian, B. Cuec and R. Ramavataram (Presses Universitè Laval, Quebec, 1975), p. 136; Th. A. Rijken, Ph. D. thesis, University of Nijmegen, 1975; M. M. Nagels, Th. A. Rijken and J. J. de Swart, Phys. Rev. D 17 (1978), 768; P. M. M. Maessen, Th. A. Rijken and J. J. de Swart, Phys. Rev. C 40 (1989), 2226; Th. A. Rijken, V. G. J. Stoks and Y. Yamamoto, Phys. Rev. C 59 (1999), 21; V. G. J. Stoks and Th. A. Rijken, Phys. Rev. C 59 (1999), 3009]. All ingredients of these latter models are also part of ESC08, and so a description of ESC08 comprises all models so far in principle. The extended-soft-core (ESC) interactions consist of local- and non-local-potentials due to (i) one-boson-exchanges (OBE), which are the members of nonets of
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
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.
Li, Ning; Wu, Ya-Jie; Liu, Zhan-Wei
2018-01-01
The relations between the baryon-baryon elastic scattering phase shifts and the two-particle energy spectrum in the elongated box are established. We studied the cases with both the periodic boundary condition and twisted boundary condition in the center of mass frame. The framework is also extended to the system of nonzero total momentum with periodic boundary condition in the moving frame. Moreover, we discussed the sensitivity functions σ (q ) that represent the sensitivity of higher scattering phases. Our analytical results will be helpful to extract the baryon-baryon elastic scattering phase shifts in the continuum from lattice QCD data by using elongated boxes.
The Extended Baryonic Halo of NGC 3923
Directory of Open Access Journals (Sweden)
Bryan W. Miller
2017-07-01
Full Text Available Galaxy halos and their globular cluster systems build up over time by the accretion of small satellites. We can learn about this process in detail by observing systems with ongoing accretion events and comparing the data with simulations. Elliptical shell galaxies are systems that are thought to be due to ongoing or recent minor mergers. We present preliminary results of an investigation of the baryonic halo—light profile, globular clusters, and shells/streams—of the shell galaxy NGC 3923 from deep Dark Energy Camera (DECam g and i-band imaging. We present the 2D and radial distributions of the globular cluster candidates out to a projected radius of about 185 kpc, or ∼ 37 R e , making this one of the most extended cluster systems studied. The total number of clusters implies a halo mass of M h ∼ 3 × 10 13 M ⊙ . Previous studies had identified between 22 and 42 shells, making NGC 3923 the system with the largest number of shells. We identify 23 strong shells and 11 that are uncertain. Future work will measure the halo mass and mass profile from the radial distributions of the shell, N-body models, and line-of-sight velocity distribution (LOSVD measurements of the shells using the Multi Unit Spectroscopic Explorer (MUSE.
Repulsive baryonic interactions and lattice QCD observables at imaginary chemical potential
Directory of Open Access Journals (Sweden)
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 â corresponding to the fugacity or virial expansion at real chemical potential â 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 Tâ185Â MeV is described fairly well by an interacting HRG with a single baryonâbaryon eigenvolume interaction parameter bâ1Â fm3, while the available lattice data on the difference Ï2BâÏ4B of baryon number susceptibilities is reproduced up to Tâ175Â MeV. Keywords: Hadron resonance gas, Excluded volume, Imaginary chemical potential
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)
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.
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)
Baryons electromagnetic mass splittings in potential models
International Nuclear Information System (INIS)
Genovese, M.; Richard, J.-M.; Silvestre-Brac, B.; Varga, K.
1998-01-01
We study electromagnetic mass splittings of charmed baryons. We point out discrepancies among theoretical predictions in non-relativistic potential models; none of these predictions seems supported by experimental data. A new calculation is presented
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.)
Unified Chiral models of mesons and baryons
International Nuclear Information System (INIS)
Mendez-Galain, R.; Ripka, G.
1990-01-01
Unified Chiral models of mesons and baryons are presented. Emphasis is placed on the underlying quark structure of hadrons including the Skyrmion. The Nambu Jona-Lasinio model with vector mesons is discussed
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
Theoretical status of baryon magnetic moments
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
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.)
Calculations for BDAS Setpoint with Non-conservative Boron Dilution Analysis
International Nuclear Information System (INIS)
Lee, Hwan Soo; Shin, Ho Cheol; Kim, Yong Bae
2014-01-01
BDAS (Boron Dilution Alarm System) utilizes the ex-core detector instrumentation signals to detect a possible inadvertent boron dilution event during operation mode 3, 4, 5, 6. For boron dilution analysis, discrepancies in the active coolant volume and the assumed linearity of the ex-core instrumentation response were identified for CE type PWR and they were reported by NASL-04-02 These discrepancies have potential to impact to determine BDAS setpoint in a non-conservative manner Therefore, in this study, the calculation of BDAS setpoint with those discrepancies condition about OPR1000 was performed and analyzed for checking the safety of BDAS. The new BDAS setpoint is calculated with conservative condition which recommended from Westinghouse Electric Company. The setpoint of BDAS using non-linear ICRR curve decrease to about 5% compared to the setpoint of that using linear ICRR curve. And this effect of the non-linearity is to slightly delay the boron dilution alarm during the inadvertence boron dilution at mode 3, 4, and 5
Self-organized criticality occurs in non-conservative neuronal networks during `up' states
Millman, Daniel; Mihalas, Stefan; Kirkwood, Alfredo; Niebur, Ernst
2010-10-01
During sleep, under anaesthesia and in vitro, cortical neurons in sensory, motor, association and executive areas fluctuate between so-called up and down states, which are characterized by distinct membrane potentials and spike rates. Another phenomenon observed in preparations similar to those that exhibit up and down states-such as anaesthetized rats, brain slices and cultures devoid of sensory input, as well as awake monkey cortex-is self-organized criticality (SOC). SOC is characterized by activity `avalanches' with a branching parameter near unity and size distribution that obeys a power law with a critical exponent of about -3/2. Recent work has demonstrated SOC in conservative neuronal network models, but critical behaviour breaks down when biologically realistic `leaky' neurons are introduced. Here, we report robust SOC behaviour in networks of non-conservative leaky integrate-and-fire neurons with short-term synaptic depression. We show analytically and numerically that these networks typically have two stable activity levels, corresponding to up and down states, that the networks switch spontaneously between these states and that up states are critical and down states are subcritical.
The baryon content of the Cosmic Web
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
Precombination Cloud Collapse and Baryonic Dark Matter
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.
The baryonic mass function of galaxies.
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.
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.
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
Few-baryon systems in the SU(2)-Skyrme model
International Nuclear Information System (INIS)
Nikolaev, V.A.; Tkachev, O.G.
1989-01-01
The classically stable solitons with baryon number 1, 2, 3, 4 have been investigated in the framework of the very general assumption about the form of the solutions for the Skyrme model equations. Some of the solitons have the toroidal structure and some of them are more complicated. The effective quantum-mechanical Hamiltonian and its spectrum are obtained by using the collective variable method. All the states with quantum numbers of light nuclei have the binding energy greater than the experimental one. Some of the calculated states containing antibaryons as substructure units should appear in the experiments with stopped antibaryons as compound nuclear states. 16 refs.; 7 figs.; 5 tabs
Disentanglement of Electromagnetic Baryon Properties
Sadasivan, Daniel; Doring, Michael
2017-01-01
Through recent advances in experimental techniques, the precise extraction of the spectrum of baryonic resonances and their properties becomes possible. Helicity couplings at the resonance pole are fundamental parameters describing the electromagnetic properties of resonances and enabling the comparison of theoretical models with data. We have extracted them from experiments carried out at Jefferson Lab and other facilities using a multipole analysis within the Julich-Bonn framework. Special attention has been paid to the uncertainties and correlations of helicity couplings. Using the world data on the reaction γp -> ηp , we have calculated, for the first time, the covariance matrix. Our results are useful in several ways. They quantify uncertainties but also correlations of helicity couplings. Second, they can tell us quantitatively how useful a given polarization measurement is. Third, they can tell us how the measurement of a new observable would constrain and disentangle the resonance properties which could be helpful in the design of new experiments. Finally, on the subject of the missing resonance problem, model selection techniques and statistical tests allow us to quantify the significance of whether a resonance exists. Supported by NSF CAREER Grant No. PHY-1452055, NSF PIF Grant No. 1415459, by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177, and by Research Center Julich through the HPC grant jikp07.
Baryon Acoustic Oscillations reconstruction with pixels
Energy Technology Data Exchange (ETDEWEB)
Obuljen, Andrej [SISSA—International School for Advanced Studies, Via Bonomea 265, 34136 Trieste (Italy); Villaescusa-Navarro, Francisco [Center for Computational Astrophysics, 160 5th Ave, New York, NY, 10010 (United States); Castorina, Emanuele [Berkeley Center for Cosmological Physics, University of California, Berkeley, CA 94720 (United States); Viel, Matteo, E-mail: aobuljen@sissa.it, E-mail: fvillaescusa@simonsfoundation.org, E-mail: ecastorina@berkeley.edu, E-mail: viel@oats.inaf.it [INAF, Osservatorio Astronomico di Trieste, via Tiepolo 11, I-34131 Trieste (Italy)
2017-09-01
Gravitational non-linear evolution induces a shift in the position of the baryon acoustic oscillations (BAO) peak together with a damping and broadening of its shape that bias and degrades the accuracy with which the position of the peak can be determined. BAO reconstruction is a technique developed to undo part of the effect of non-linearities. We present and analyse a reconstruction method that consists of displacing pixels instead of galaxies and whose implementation is easier than the standard reconstruction method. We show that this method is equivalent to the standard reconstruction technique in the limit where the number of pixels becomes very large. This method is particularly useful in surveys where individual galaxies are not resolved, as in 21cm intensity mapping observations. We validate this method by reconstructing mock pixelated maps, that we build from the distribution of matter and halos in real- and redshift-space, from a large set of numerical simulations. We find that this method is able to decrease the uncertainty in the BAO peak position by 30-50% over the typical angular resolution scales of 21 cm intensity mapping experiments.
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
Strangeness S = -2 baryon-baryon interactions using chiral effective field theory
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
Boltzmann equation for a mixture of gases with non-conservative processes
International Nuclear Information System (INIS)
Martiarena, M.L.
1989-01-01
The nonlinear and non-isotropic Boltzmann equation (NLBE) including several molecular species, non-conservative channels and external forces. The general solution of that equation is obtained for a spatially homogeneous mixture of L gases, consisting of Maxwell particles, as a Generalized Laguerre expansion, within a Hilbert space. Removal and self-generation effects are included in presence of a time-dependent external force. An exact particular solution is studied generalizing the well-known BKW-mode for a mixture of L gases with inelastic processes. An homogeneous gas of test particles, in d dimension, is considered which interacts with a background host medium in the presence of an external space and time dependent force. Scattering, removal and self-generation collisions are included. The inhomogeneous Boltzmann equation for this system to an homogeneous one is reduced without background or external forces, using a generalized Nilkoskii transform. It is shown that a background of field particles can confine the test gas, even in absence of external forces. Furthermore, the solution of NLBE with non-isotropic singular initial conditions, is analyzed. The NLBE is transformed into an integral equation which is solved iteratively. The evolution of delta and step singularities in the distribution function is discussed during the initial layer and compared with the isotropic case. As an application of the methods abovementioned, the collision of a beam of ions or neutral atoms with a carbon-foil is considered. The electron experimental spectra from a transport equation is described. It is supposed that convoy electron may be produced inside the solid by single ion-atom collisions as ELC or ECC. The produced electrons lost energy by collision with the atoms of the material, which are considered at rest. The electron distribution function is numerically calculated. The ratio between the intrinsic convoy electron peak height to the background electron intensity
Suryaputra, I. G. N. A.; Santos, I. R.; Huettel, M.; Burnett, W. C.; Dittmar, T.
2015-11-01
The role of submarine groundwater discharge (SGD) in releasing fluorescent dissolved organic matter (FDOM) to the coastal ocean and the possibility of using FDOM as a proxy for dissolved organic carbon (DOC) was investigated in a subterranean estuary in the northeastern Gulf of Mexico (Turkey Point, Florida). FDOM was continuously monitored for three weeks in shallow beach groundwater and in the adjacent coastal ocean. Radon (222Rn) was used as a natural groundwater tracer. FDOM and DOC correlated in groundwater and seawater samples, implying that FDOM may be a proxy of DOC in waters influenced by SGD. A mixing model using salinity as a seawater tracer revealed FDOM production in the high salinity region of the subterranean estuary. This production was probably a result of infiltration and transformation of labile marine organic matter in the beach sediments. The non-conservative FDOM behavior in this subterranean estuary differs from most surface estuaries where FDOM typically behaves conservatively. At the study site, fresh and saline SGD delivered about 1800 mg d-1 of FDOM (quinine equivalents) to the coastal ocean per meter of shoreline. About 11% of this input was related to fresh SGD, while 89% were related to saline SGD resulting from FDOM production within the shallow aquifer. If these fluxes are representative of the Florida Gulf Coast, SGD-derived FDOM fluxes would be equivalent to at least 18% of the potential regional riverine FDOM inputs. To reduce uncertainties related to the scarcity of FDOM data, further investigations of river and groundwater FDOM inputs in Florida and elsewhere are necessary.
Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefiev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Jin, B.N.; Jindal, P.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, J.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Pal, I.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Piccolo, D.; Pierella, F.; Pieri, M.; Pioppi, M.; PirouLe, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofiev, D.; Rahal-Callot, G.; Rahaman, Mohammad Azizur; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Rembeczki, S.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosemann, C.; Rosenbleck, C.; Rosier-Lees, S.; Roth, Stefan; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Vesztergombi, G.; Vetlitsky, I.; Viertel, G.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, An.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.
2007-01-01
Measurements of inclusive production of the Lambda, Xi- and Xi*(1530) baryons in two-photon collisions with the L3 detector at LEP are presented. The inclusive differential cross sections for Lambda and Xi- are measured as a function of the baryon transverse momentum, pt, and pseudo-rapidity, eta. The mean number of Lambda, Xi- and Xi*(1530) baryons per hadronic two-photon event is determined in the kinematic range 0.4 GeV proton K0s is also presented. No evidence for production of this state is found.
Meson and baryon families as vibronic states in sl(2) quantum universal enveloping algebra
International Nuclear Information System (INIS)
Iwao, Syurei; Ono, Yasuji
1990-01-01
A mass formula of the q-deformed modified harmonic oscillator type in the sl(2) quantum universal enveloping algebra is proposed for the meson and baryon families, by taking into account the known theories as a guide. Specifying the vibronic quantum number, the deformation parameter and associated ones of the theory are determined from available data for the scalar, pseudoscalar, vector meson and baryon families. The parameters determined from totally ten families not only predict many unobserved states, but also give restrictions on the observable number of states. The method may admit taking into account non-perturbative effects. (author)
QCD inequalities for the nucleon mass and the free energy of baryonic matter.
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.
Emergence of the mass discrepancy-acceleration relation from dark matter-baryon interactions
Famaey, Benoit; Khoury, Justin; Penco, Riccardo
2018-03-01
The observed tightness of the mass discrepancy-acceleration relation (MDAR) poses a fine-tuning challenge to current models of galaxy formation. We propose that this relation could arise from collisional interactions between baryons and dark matter (DM) particles, without the need for modification of gravity or ad hoc feedback processes. We assume that these interactions satisfy the following three conditions: (i) the relaxation time of DM particles is comparable to the dynamical time in disk galaxies; (ii) DM exchanges energy with baryons due to elastic collisions; (iii) the product between the baryon-DM cross section and the typical energy exchanged in a collision is inversely proportional to the DM number density. As a proof of principle, we present an example of a particle physics model that gives a DM-baryon cross section with the desired density and velocity dependence. For consistency with direct detection constraints, our DM particles must be either very light (m ll mb) or very heavy (mgg mb), corresponding respectively to heating and cooling of DM by baryons. In both cases, our mechanism applies and an equilibrium configuration can in principle be reached. In this exploratory paper, we focus on the heavy DM/cooling case because it is technically simpler, since the average energy exchanged turns out to be approximately constant throughout galaxies. Under these assumptions, we find that rotationally-supported disk galaxies could naturally settle to equilibrium configurations satisfying a MDAR at all radii without invoking finely tuned feedback processes. We also discuss issues related to the small scale clumpiness of baryons, as well as predictions for pressure-supported systems. We argue in particular that galaxy clusters do not follow the MDAR despite being DM-dominated because they have not reached their equilibrium configuration. Finally, we revisit existing phenomenological, astrophysical and cosmological constraints on baryon-DM interactions in light
Multi-scale coarse-graining of non-conservative interactions in molecular liquids
International Nuclear Information System (INIS)
Izvekov, Sergei; Rice, Betsy M.
2014-01-01
A new bottom-up procedure for constructing non-conservative (dissipative and stochastic) interactions for dissipative particle dynamics (DPD) models is described and applied to perform hierarchical coarse-graining of a polar molecular liquid (nitromethane). The distant-dependent radial and shear frictions in functional-free form are derived consistently with a chosen form for conservative interactions by matching two-body force-velocity and three-body velocity-velocity correlations along the microscopic trajectories of the centroids of Voronoi cells (clusters), which represent the dissipative particles within the DPD description. The Voronoi tessellation is achieved by application of the K-means clustering algorithm at regular time intervals. Consistently with a notion of many-body DPD, the conservative interactions are determined through the multi-scale coarse-graining (MS-CG) method, which naturally implements a pairwise decomposition of the microscopic free energy. A hierarchy of MS-CG/DPD models starting with one molecule per Voronoi cell and up to 64 molecules per cell is derived. The radial contribution to the friction appears to be dominant for all models. As the Voronoi cell sizes increase, the dissipative forces rapidly become confined to the first coordination shell. For Voronoi cells of two and more molecules the time dependence of the velocity autocorrelation function becomes monotonic and well reproduced by the respective MS-CG/DPD models. A comparative analysis of force and velocity correlations in the atomistic and CG ensembles indicates Markovian behavior with as low as two molecules per dissipative particle. The models with one and two molecules per Voronoi cell yield transport properties (diffusion and shear viscosity) that are in good agreement with the atomistic data. The coarser models produce slower dynamics that can be appreciably attributed to unaccounted dissipation introduced by regular Voronoi re-partitioning as well as by larger
Multi-scale coarse-graining of non-conservative interactions in molecular liquids
Energy Technology Data Exchange (ETDEWEB)
Izvekov, Sergei, E-mail: sergiy.izvyekov.civ@mail.mil; Rice, Betsy M. [U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States)
2014-03-14
A new bottom-up procedure for constructing non-conservative (dissipative and stochastic) interactions for dissipative particle dynamics (DPD) models is described and applied to perform hierarchical coarse-graining of a polar molecular liquid (nitromethane). The distant-dependent radial and shear frictions in functional-free form are derived consistently with a chosen form for conservative interactions by matching two-body force-velocity and three-body velocity-velocity correlations along the microscopic trajectories of the centroids of Voronoi cells (clusters), which represent the dissipative particles within the DPD description. The Voronoi tessellation is achieved by application of the K-means clustering algorithm at regular time intervals. Consistently with a notion of many-body DPD, the conservative interactions are determined through the multi-scale coarse-graining (MS-CG) method, which naturally implements a pairwise decomposition of the microscopic free energy. A hierarchy of MS-CG/DPD models starting with one molecule per Voronoi cell and up to 64 molecules per cell is derived. The radial contribution to the friction appears to be dominant for all models. As the Voronoi cell sizes increase, the dissipative forces rapidly become confined to the first coordination shell. For Voronoi cells of two and more molecules the time dependence of the velocity autocorrelation function becomes monotonic and well reproduced by the respective MS-CG/DPD models. A comparative analysis of force and velocity correlations in the atomistic and CG ensembles indicates Markovian behavior with as low as two molecules per dissipative particle. The models with one and two molecules per Voronoi cell yield transport properties (diffusion and shear viscosity) that are in good agreement with the atomistic data. The coarser models produce slower dynamics that can be appreciably attributed to unaccounted dissipation introduced by regular Voronoi re-partitioning as well as by larger
S-matrix analysis of the baryon electric charge correlation
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.
Search for exotic baryons with the Sphinx facility
International Nuclear Information System (INIS)
Landsberg, L.G.
1993-01-01
In the experiments at the Sphinx facility in the proton beam of the IHEP accelerator (E p = 70 GeV) a number of diffractive production reactions were studied. Among them are p + N → (K + K - p) + N, p + N → (φp) + N, p + N → [Λ(1520)K + ] + N, p + N → [Σ(1385) 0 K + ] + N, as well as some other processes. The results of the search for narrow heavy baryon states, candidates for the cryptoexotic hadrons with hidden strangeness, are presented. 15 refs., 5 figs., 1 tab
Spinodal instability of baryon-rich quark matter
International Nuclear Information System (INIS)
Li, Feng; Ko, Che Ming
2017-01-01
The spinodal instabilities of both confined and expanding baryon-rich quark matters are studied in a transport model derived from the Nambu-Jona-Lasino model. Appreciable higher-order density moments are seen as a result of the first-order phase transition in both cases. The skewness of the quark number event-by-event distribution in a small subvolume of the system becomes appreciable for the confined quark matter. For the expanding quark matter, the density fluctuations lead to enhanced anisotropic flows and dilepton yield. (paper)
Lattice QCD for Baryon Rich Matter – Beyond Taylor Expansions
Energy Technology Data Exchange (ETDEWEB)
Bornyakov, V. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Boyda, D. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Goy, V. [School of Natural Sciences, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Molochkov, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Nakamura, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka, 567-0047 (Japan); Theoretical Research Division, Nishina Center, RIKEN, Wako 351-0198 (Japan); Nikolaev, A. [School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Zakharov, V.I. [ITEP, B. Cheremushkinskaya 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Sukhanova 8, Vladivostok 690950 (Russian Federation); Moscow Inst Phys & Technol, Dolgoprudny, Moscow Region, 141700 (Russian Federation)
2016-12-15
We discuss our study for exploring the QCD phase diagram based on the lattice QCD. To go beyond the Taylor expansion and to reach higher density regions, we employ the canonical approach. In order to produce lattice data which meet experimental situation as much as possible, we propose a canonical approach with the charge and baryon number. We present our lattice QCD GPU code for this project which employs the clover improved Wilson fermions and Iwasaki gauge action to investigate pure imaginary chemical potential.
Lattice QCD for Baryon Rich Matter – Beyond Taylor Expansions
International Nuclear Information System (INIS)
Bornyakov, V.; Boyda, D.; Goy, V.; Molochkov, A.; Nakamura, A.; Nikolaev, A.; Zakharov, V.I.
2016-01-01
We discuss our study for exploring the QCD phase diagram based on the lattice QCD. To go beyond the Taylor expansion and to reach higher density regions, we employ the canonical approach. In order to produce lattice data which meet experimental situation as much as possible, we propose a canonical approach with the charge and baryon number. We present our lattice QCD GPU code for this project which employs the clover improved Wilson fermions and Iwasaki gauge action to investigate pure imaginary chemical potential.
Net-baryon number fluctuations using Tsallis statistics
International Nuclear Information System (INIS)
Garg, P.; Singh, B.K.; Mishra, D.K.; Netrakanti, P.K.; Mohanty, A.K.
2014-01-01
In the present work, we show that the HRG-Tsallis model with a temperature dependent nonextensive q parameter reproduces the energy dependence of Sσ and kσ 2 for most peripheral collisions as well as Sσ for central collisions. However, the energy dependence of kσ 2 of central collision deviate significantly from the HRG-Tsallis model predictions particularly at energies 19.6 GeV and 27 GeV. We argue here that the predictions of HRG-Tsallis characterized by a temperature dependent q parameter should be taken as the baseline to study (experimentally) fluctuations of dynamical origin if any, which is still not contained in the Tsallis non-extensive thermodynamics
QCD bound states at finite temperature and baryon number
International Nuclear Information System (INIS)
Kalinovsky, Yu.L.; Muenchow, L.
1991-04-01
Quark-antiquark bound states are described within the Bethe-Salpeter equation for a class of quark models with instantaneous 4-quark interaction at finite temperature. Thereby decompositions of the Bethe-Salpeter vertex and wave functions according to their Lorentz structures and the particles content are used. As an application of general scheme, we determine the mass spectrum of low-lying mesons for a special Nambu-Jona-Lasinio model inspired by QCD for hadrons. (orig.)
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
Atomic parity non-conservation: the francium anapole project of the FrPNC collaboration at TRIUMF
Energy Technology Data Exchange (ETDEWEB)
Aubin, S. [College of William and Mary, Dept. Physics (United States); Behr, J. A. [TRIUMF (Canada); Collister, R. [University of Manitoba, Dept. of Physics and Astronomy (Canada); Flambaum, V. V. [University of New South Wales, School of Physics (Australia); Gomez, E. [Universidad Autonoma de San Luis Potosi, Instituto de Fisica (Mexico); Gwinner, G. [University of Manitoba, Dept. of Physics and Astronomy (Canada); Jackson, K. P. [TRIUMF (Canada); Melconian, D. [Texas A and M University, Cyclotron Institute (United States); Orozco, L. A., E-mail: lorozco@umd.edu [University of Maryland, JQI, Dept. of Physics, and NIST (United States); Pearson, M. R. [TRIUMF (Canada); Sheng, D. [Princeton University (United States); Sprouse, G. D. [Stony Brook University, Dept. of Physics and Astronomy (United States); Tandecki, M. [TRIUMF (Canada); Zhang, J. [University of Maryland, JQI, Dept. of Physics, and NIST (United States); Zhao, Y. [Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices (China)
2013-03-15
We present a method for measuring the nuclear anapole in a string of francium isotopes. The anapole is a parity non-conserving electromagnetic moment that enables parity-forbidden transitions between ground state hyperfine levels of an atom. The experiment is run by the FrPNC collaboration and relies on a beam of artificially-produced francium from the ISAC facility at TRIUMF.
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.)
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)
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
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
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
On finite volume effects in the chiral extrapolation of baryon masses
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.
Measurement of the average polarization of b baryons in hadronic $Z^0$ decays
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.
Gauge unified theories and the problem of origin of Universe baryon asymmetry
International Nuclear Information System (INIS)
Ignat'ev, A.Yu.; Kuz'min, V.A.; Shaposhnikov, M.E.
1981-01-01
Explanation of origin of the Universe baryon asymmetry (UBA) has been attempted within the framework of united gauge theories (UGT) of strong, electromagnetic and weak interactions. Different approaches to the UBA formation problem have been discussed. Considered was the most natural approach from the point of view of particle physics: the singular state of the baryon-antibaryon system is symmetrical but the baryon number and CP invariance are not retained and UBA arises in processes with elementary particles at the thermodynamically nonequilibrium stage of the Universe expansion. A UBA generation mechanism based on a hypothesis of the thermodynamic equilibrium in the expanded Universe at the expense of quantum-gravitational interactions is suggested. A problem of the explanation of the UBA existence with the synthesis of UGT and of the theory of the hot Universe was investigated in detail. Macroscopic factors of the baryon asymmetry suppression in deacys of vector and scalar particles have been determined. The baryon asymmetry calculations have been performed within the framework of the SU(5) model with the Higgs expanded sector. In is concluded that within the framework of UGT, on the assumptions of scalar particle masses, a possibility for explaining the asymmetry value, the calculated value of which is close to the value observed experimentally, appears [ru
Three particle Poincare states and SU(6) x SU(3) as a classification group for baryons
International Nuclear Information System (INIS)
Buccella, F.; Sciarrino, A.; Sorba, P.
1975-05-01
A complete set of democratic quantum numbers is introduced to classify the states of an irreducible unitary representation (IUR) of the Poincare group obtained from the decomposition of the direct products of three I.U.R. Such states are identified with the baryon states constituted of three free relativistic quarks. The transformation from current to constituent quarks is then easily reobtained. Moreover, the group SU(6) x SU(3) appears naturally as a collinear classification group for baryons. Results similar to those of the symmetric harmonic oscillator quark model are obtained [fr
Rotational-vibrational coupling in the BPS Skyrme model of baryons
Energy Technology Data Exchange (ETDEWEB)
Adam, C.; Naya, C.; Sanchez-Guillen, J. [Departamento de Física de Partículas, Universidad de Santiago de Compostela and Instituto Galego de Física de Altas Enerxias (IGFAE), E-15782 Santiago de Compostela (Spain); Wereszczynski, A. [Institute of Physics, Jagiellonian University, Reymonta 4, Kraków (Poland)
2013-11-04
We calculate the rotational-vibrational spectrum in the BPS Skyrme model for the hedgehog skyrmion with baryon number one. The resulting excitation energies for the nucleon and delta Roper resonances are slightly above their experimental values. Together with the fact that in the standard Skyrme model these excitation energies are significantly lower than the experimental ones, this provides strong evidence for the conjecture that the inclusion of the BPS Skyrme model is required for a successful quantitative description of physical properties of baryons and nuclei.
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
Excited-state spectroscopy of singly, 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
2014-07-01
We present the ground and excited state spectra of singly, doubly and triply-charmed baryons by using dynamical lattice QCD. A large set of baryonic operators that respect the symmetries of the lattice and are obtained after subduction from their continuum analogues are utilized. These operators transform as irreducible representations of SU(3)F symmetry for flavour, SU(4) symmetry for Dirac spins of quarks and O(3) symmetry for orbital angular momenta. 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.
Temperature and baryon-chemical-potential-dependent bag pressure for a deconfining phase transition
International Nuclear Information System (INIS)
Patra, B.K.; Singh, C.P.
1996-01-01
We explore the consequences of a bag model developed by Leonidov et al. for the deconfining phase transition in which the bag pressure is made to depend on the temperature and baryon chemical potential in order to ensure the entropy and baryon number conservation at the phase boundary together with the Gibbs construction for an equilibrium phase transition. We show that the bag pressure thus obtained yields an anomalous increasing behavior with the increasing baryon chemical potential at a fixed temperature which defies a physical interpretation. We demonstrate that the inclusion of the perturbative interactions in the QGP phase removes this difficulty. Further consequences of the modified bag pressure are discussed. copyright 1996 The American Physical Society
Multistrange Baryon elliptic flow in Au+Au collisions at square root of sNN=200 GeV.
Adams, J; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Berger, J; Bezverkhny, B I; Bharadwaj, S; Bhasin, A; Bhati, A K; Bhatia, V S; Bichsel, H; Bielcik, J; Bielcikova, J; Billmeier, A; Bland, L C; Blyth, C O; Blyth, S L; Bonner, B E; Botje, M; Boucham, A; Bouchet, J; Brandin, A V; Bravar, A; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, Y; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Das, S; Daugherity, M; de Moura, M M; Dedovich, T G; DePhillips, M; Derevschikov, A A; Didenko, L; Dietel, T; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Mazumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faivre, J; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Y; Fornazier, K S F; Fu, J; Gagliardi, C A; Gaillard, L; Gans, J; Ganti, M S; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Gos, H; Grachov, O; Grebenyuk, O; Grosnick, D; Guertin, S M; Guo, Y; Gupta, A; Gupta, N; Gutierrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Jedynak, M; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kaplan, M; Keane, D; Kechechyan, A; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Kislov, E M; Klay, J; Klein, S R; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kowalik, K L; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lehocka, S; LeVine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Q J; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahajan, S; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J N; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Miller, M L; Minaev, N G; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Reinnarth, J; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Sarsour, M; Savin, I; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shen, W Q; Shestermanov, K E; Shimanskiy, S S; Sichtermann, E; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T; Thein, D; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; van der Kolk, N; van Leeuwen, M; Vander Molen, A M; Varma, R; Vasilevski, I M; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, G; Wang, X L; Wang, Y; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Zborovsky, I; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhong, C; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X
2005-09-16
We report on the first measurement of elliptic flow v2(pT) of multistrange baryons Xi- +Xi+ and Omega- + Omega+ in heavy-ion collisions. In minimum-bias Au+Au collisions at square root of s(NN)=200 GeV, a significant amount of elliptic flow, comparable to other nonstrange baryons, is observed for multistrange baryons which are expected to be particularly sensitive to the dynamics of the partonic stage of heavy-ion collisions. The pT dependence of v2 of the multistrange baryons confirms the number of constituent quark scaling previously observed for lighter hadrons. These results support the idea that a substantial fraction of the observed collective motion is developed at the early partonic stage in ultrarelativistic nuclear collisions at the Relativistic Heavy Ion Collider.
General analysis of weak decay form factors in heavy to heavy and heavy to light baryon transitions
International Nuclear Information System (INIS)
Hussain, F.; Liu Dongsheng; Kraemer, M.; Koerner, J.G.; Tawfiq, S.
1992-01-01
We present a complete analysis of the heavy to heavy and heavy to light baryon semi-leptonic decays in the heavy quark effective theory within the framework of a Bethe-Salpeter (BS) approach and demonstrate the equivalence of this approach to other work in the field. We present in a compact form the baryon BS amplitudes which incorporate the symmetries manifest in the heavy quark limit and which also show clearly the light quark dynamics. A similar form of the BS amplitude is presented for light baryons. Using the BS amplitudes, the heavy to heavy and heavy to light semi-leptonic baryon decays are considered. As expected there is a dramatic reduction in the number of form factors. An advantage of our BS approach is demonstrated where the form factors are written as loop integrals which in principle can be calculated. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Knippschild, Bastian
2012-03-05
Quantum Chromodynamics (QCD) is the theory of strong interactions, one of the four fundamental forces in our Universe. It describes the interaction of gluons and quarks which build up hadrons like protons and neutrons. Most of the visible matter in our universe is made of protons and neutrons. Hence, we are interested in their fundamental properties like their masses, their distribution of charge and their shape. The only known theoretical, non-perturbative and ab initio method to investigate hadron properties at low energies is lattice Quantum Chromodynamics (lattice QCD). However, up-to-date simulations (especially for baryonic quantities) do not achieve the accuracy of experiments. In fact, current simulations do not even reproduce the experimental values for the form factors. The question arises wether these deviations can be explained by systematic effects in lattice QCD simulations. This thesis is about the computation of nucleon form factors and other hadronic quantities from lattice QCD. So called Wilson fermions are used and the u- and d-quarks are treated fully dynamically. The simulations were performed using gauge ensembles with a range of lattice spacings, volumes and pion masses. First of all, the lattice spacing was set to be able to make contact between the lattice results and their experimental complement and to be able to perform a continuum extrapolation. The light quark mass has been computed and found to be m{sub ud}{sup MS}(2 GeV)=3.03(17)(38) MeV. This value is in good agreement with values from experiments and other lattice determinations. Electro-magnetic and axial form factors of the nucleon have been calculated. From these form factors the nucleon radii and the coupling constants were computed. The different ensembles enabled us to investigate systematically the dependence of these quantities on the volume, the lattice spacing and the pion mass. Finally we perform a continuum extrapolation and chiral extrapolations to the physical point
International Nuclear Information System (INIS)
Knippschild, Bastian
2012-01-01
Quantum Chromodynamics (QCD) is the theory of strong interactions, one of the four fundamental forces in our Universe. It describes the interaction of gluons and quarks which build up hadrons like protons and neutrons. Most of the visible matter in our universe is made of protons and neutrons. Hence, we are interested in their fundamental properties like their masses, their distribution of charge and their shape. The only known theoretical, non-perturbative and ab initio method to investigate hadron properties at low energies is lattice Quantum Chromodynamics (lattice QCD). However, up-to-date simulations (especially for baryonic quantities) do not achieve the accuracy of experiments. In fact, current simulations do not even reproduce the experimental values for the form factors. The question arises whether these deviations can be explained by systematic effects in lattice QCD simulations. This thesis is about the computation of nucleon form factors and other hadronic quantities from lattice QCD. So called Wilson fermions are used and the u- and d-quarks are treated fully dynamically. The simulations were performed using gauge ensembles with a range of lattice spacings, volumes and pion masses. First of all, the lattice spacing was set to be able to make contact between the lattice results and their experimental complement and to be able to perform a continuum extrapolation. The light quark mass has been computed and found to be m ud MS (2 GeV)=3.03(17)(38) MeV. This value is in good agreement with values from experiments and other lattice determinations. Electro-magnetic and axial form factors of the nucleon have been calculated. From these form factors the nucleon radii and the coupling constants were computed. The different ensembles enabled us to investigate systematically the dependence of these quantities on the volume, the lattice spacing and the pion mass. Finally we perform a continuum extrapolation and chiral extrapolations to the physical point. In
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.)
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
Multiquark baryons with broken flavour symmetry 1
International Nuclear Information System (INIS)
Wroldsen, J.
The calculation of the spectrum of 4qq multiquark baryons is carried out, taking into account that SU(3) flavour is broken. To handle this problem, which includes manipulation of giant expressions for the wavefunctions, methods suitable for programming in SCHOONSCHIP are developed and employed. (Auth)
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.
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.)
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.
Weak radiative baryonic decays of B mesons
International Nuclear Information System (INIS)
Kohara, Yoji
2004-01-01
Weak radiative baryonic B decays B→B 1 B 2 -barγ are studied under the assumption of the short-distance b→sγ electromagnetic penguin transition dominance. The relations among the decay rates of various decay modes are derived
CP asymmetries in Strange Baryon Decays
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 production in proton-proton collisions
International Nuclear Information System (INIS)
Liu, F.M.; Werner, K.
2002-01-01
Motivated by the recent rapidity spectra of baryons and antibaryons in pp collisions at 158 GeV and the Ω-bar/Ω ratio discussion, we reviewed string formation mechanism and some string models. This investigation told us how color strings are formed in ultrarelativistic proton-proton collisions
Baryon asymmetry from Planck-scale physics
International Nuclear Information System (INIS)
Gelmini, G.; Holman, R.; Carnegie-Mellon Univ., Pittsburgh, PA
1992-06-01
It has been noted recently that Planck scale physics may induce the explicit breaking of global symmetries. We point out that in Majoron models, these explicit breakings, combined with sphaleron induced violation of B + L can give rise to the baryon asymmetry of the Universe
Large N baryons, strong coupling theory, quarks
International Nuclear Information System (INIS)
Sakita, B.
1984-01-01
It is shown that in QCD the large N limit is the same as the static strong coupling limit. By using the static strong coupling techniques some of the results of large N baryons are derived. The results are consistent with the large N SU(6) static quark model. (author)
Beauty baryons produced in pp interactions
International Nuclear Information System (INIS)
Fridman, A.
1996-01-01
For pp interactions, we discuss the beauty-baryon (N b ), production and decay, using cross-section estimates at a c.m. energy corresponding to the LHC project (√s ≅ 14 TeV). The polarization measurement of N b as well as the search for CP violation effects in their decays is discussed. (orig.)
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)
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
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.)
Do the weak neutral currents cause parity non-conserving eN and μN forces
International Nuclear Information System (INIS)
Henley, E.M.
1977-01-01
It is stated that although the evidence for weak neutral currents is now well established its effects have been observed primarily in reactions initiated by muon neutrinos in which the neutrino is also present in the final state. There is, as yet, no comparable evidence for a weak force due to neutral currents, mediated by an uncharged boson, between charged leptons (electrons, muons) and nucleons. Theory predicts such a force, but its detection requires it to be parity non-conserving, since any weak parity conserving force is masked by the much larger electromagnetic interaction between the charged lepton and proton. Although high energy neutrino experiments favor a parity non-conserving interaction, the evidence is not overwhelming, and pure vector current theories cannot be ruled out. The electromagnetic current which is related directly to the weak force in modern gauge theories, behaves, as a pure vector under rotations and reflections, but the charged weak currents, responsible for ordinary β decays, are known to be of a mixed vector-axial vector nature. It is therefore of great interest to learn the spatial characteristics of the neutral weak currents. The search for parity non-conserving (PNC) effects in electron-nucleon scattering, in muonic atoms and in normal electronic atoms, has received much attention, but the experiments require very high precision and great care and ingenuity. The variety of ways for searching for PNC effects are discussed, together with the basic framework for most PNC theories, restricted to vector and axial-vector currents. One method to learn about the e-N weak force is to scatter longitudinally polarized electrons from protons, and the advantages of this are discussed - such tests are being undertaken. Experiments with muonic and normal electronic atoms are referred to, and their advantages and disadvantages are discussed. It is pointed out that a pleasant feature of the weak interaction is that perturbation theory can be used
Evidence for non-conservative current-induced forces in the breaking of Au and Pt atomic chains
Sabater, Carlos; Untiedt, Carlos; van Ruitenbeek, Jan M
2015-01-01
This experimental work aims at probing current-induced forces at the atomic scale. Specifically it addresses predictions in recent work regarding the appearance of run-away modes as a result of a combined effect of the non-conservative wind force and a ‘Berry force’. The systems we consider here are atomic chains of Au and Pt atoms, for which we investigate the distribution of break down voltage values. We observe two distinct modes of breaking for Au atomic chains. The breaking at high volta...
Semileptonic Decays of Heavy Omega Baryons in a Quark Model
International Nuclear Information System (INIS)
Muslema Pervin; Winston Roberts; Simon Capstick
2006-01-01
The semileptonic decays of (Omega) c and (Omega) b are treated in the framework of a constituent quark model developed in a previous paper on the semileptonic decays of heavy Λ baryons. Analytic results for the form factors for the decays to ground states and a number of excited states are evaluated. For (Omega) b to (Omega) c the form factors obtained are shown to satisfy the relations predicted at leading order in the heavy-quark effective theory at the non-recoil point. A modified fit of nonrelativistic and semirelativistic Hamiltonians generates configuration-mixed baryon wave functions from the known masses and the measured Λ c + → Λe + ν rate, with wave functions expanded in both harmonic oscillator and Sturmian bases. Decay rates of (Omega) b to pairs of ground and excited (Omega) c states related by heavy-quark symmetry calculated using these configuration-mixed wave functions are in the ratios expected from heavy-quark effective theory, to a good approximation. Our predictions for the semileptonic elastic branching fraction of (Omega) Q vary minimally within the models we use. We obtain an average value of (84 ± 2%) for the fraction of (Omega) c → Ξ (*) decays to ground states, and 91% for the fraction of (Omega) c → (Omega) (*) decays to the ground state (Omega). The elastic fraction of (Omega) b → (Omega) c ranges from about 50% calculated with the two harmonic-oscillator models, to about 67% calculated with the two Sturmian models
Magnetic moments of the lowest-lying singly heavy baryons
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.
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.)
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.
Odd-parity baryons: progress and problems
International Nuclear Information System (INIS)
Cutkosky, R.E.
1981-01-01
The odd-parity baryons have provided a graveyard for many cherished ideas about hadrons. The simple quark shell model, with QCD-inspired phenomenological perturbations, is the only model able to describe the states with even partial qualitative success. There are also important unexplained residual dynamical effects. Resonance decays can be accounted for, provided the usual spectator model is abandoned. Better experimental data could help to sort out the many remaining puzzles
Candidates for non-baryonic dark matter
International Nuclear Information System (INIS)
Fornengo, Nicolao
2002-01-01
This report is a brief review of the efforts to explain the nature of non-baryonic dark matter and of the studies devoted to the search for relic particles. Among the different dark matter candidates, special attention is devoted to relic neutralinos, by giving an overview of the recent calculations of its relic abundance and detection rates in a wide variety of supersymmetric schemes
Candidates for non-baryonic dark matter
Fornengo, Nicolao
2002-01-01
This report is a brief review of the efforts to explain the nature of non-baryonic dark matter and of the studies devoted to the search for relic particles. Among the different dark matter candidates, special attention is devoted to relic neutralinos, by giving an overview of the recent calculations of its relic abundance and detection rates in a wide variety of supersymmetric schemes.
The compressed baryonic matter experiment at FAIR
International Nuclear Information System (INIS)
Senger, Peter
2015-01-01
Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At top RHIC and LHC energies, the QCD phase diagram is studied at very high temperatures and very low net-baryon densities. These conditions presumably existed in the early universe about a microsecond after the big bang. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure such as a critical point, a first order phase transition between hadronic and partonic matter, or new phases like quarkyonic matter. The experimental discovery of these prominent landmarks of the QCD phase diagram would be a major breakthrough in our understanding of the properties of nuclear matter. The Compressed Baryonic Matter (CBM) experiment will be one of the major scientific pillars of the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The goal of the CBM research program is to explore the QCD phase diagram in the region of high baryon densities using high-energy nucleus-nucleus collisions. This includes the study of the equation-of-state of nuclear matter at neutron star core densities, and the search for the deconfinement and chiral phase transitions. The CBM detector is designed to measure rare diagnostic probes such as multi-strange hyperons, charmed particles and vector mesons decaying into lepton pairs with unprecedented precision and statistics. Most of these particles will be studied for the first time in the FAIR energy range. In order to achieve the required precision, the measurements will be performed at very high reaction rates of 100 kHz to 10 MHz. This requires very fast and radiation-hard detectors, and a novel data read-out and analysis concept based on free streaming front-end electronics and a high-performance computing cluster for online event selection. The layout, the physics performance, and the status of the proposed CBM experimental facility
Negative parity non-strange baryons
International Nuclear Information System (INIS)
Stancu, F.; Stassart, P.
1991-01-01
Our previous study is extended to negative parity baryon resonances up to J=(9/2) - . The framework is a semi-relativistic constituent quark model. The quark-quark interaction contains a Coulomb plus linear confinement terms and a short distance spin-spin and tensor terms. It is emphasized that a linear confinement potential gives too large a mass to the D 35 (1930) resonance. (orig.)
Heavy baryon spectroscopy with relativistic kinematics
International Nuclear Information System (INIS)
Valcarce, A.; Garcilazo, H.; Vijande, J.
2014-01-01
We present a comparative Faddeev study of heavy baryon spectroscopy with nonrelativistic and relativistic kinematics. We show results for different standard hyperfine interactions with both kinematics in an attempt to learn about the light quark dynamics. We highlight the properties of particular states accessible in nowadays laboratories that would help in discriminating between different dynamical models. The advance in the knowledge of light quark dynamics is a key tool for the understanding of the existence of exotic hadrons.
Charmed baryons photoproduced in FOCUS at Fermilab
Ratti, S P
2001-01-01
FOCUS collected over 7 * 10/sup 7/ triggers and more than 10/sup 6/ fully reconstructed charm particles in a photoproduction experiment at Fermilab. The experimental setup is an upgraded version of a multiparticle spectrometer used in the previous experiment E687. Data on charmed meson spectroscopy have been presented by F.L Fabbri in this Section. Here data on photoproduction of charmed baryons are presented.
Determining properties of baryon resonances in nuclei
International Nuclear Information System (INIS)
Johnson, M.B.; Chen, C.M.; Ernst, D.J.; Jiang, M.F.
1996-01-01
Meson-nucleus and photon-nucleus interactions are important sources of information about the medium modifications of baryon resonances in nuclei. Indications of how large the medium effects are for resonances above the Δ 33 (1232) are provided by it combined analysis of photonuclear and pion cross sections in the GeV range of energies. Tile existing data indicate a possible 10-20% renormalization of the pion coupling to higher-lying resonances in nuclei
Critical Opalescence in Baryonic QCD Matter
Antoniou, N. G.; Diakonos, F. K.; Kapoyannis, A. S.; Kousouris, K. S.
2006-01-01
We show that critical opalescence, a clear signature of second-order phase transition in conventional matter, manifests itself as critical intermittency in QCD matter produced in experiments with nuclei. This behaviour is revealed in transverse momentum spectra as a pattern of power laws in factorial moments, to all orders, associated with baryon production. This phenomenon together with a similar effect in the isoscalar sector of pions (sigma mode) provide us with a set of observables associ...
Baryon production in e+e- annihilation
International Nuclear Information System (INIS)
Saxon, D.H.
1988-11-01
The phenomenology of baryon production in high energy e + e - annihilation is described. Much can be understood in terms of mass effects. Comparisons with the rates for different flavours and spins, with momentum and transverse momentum spectra and with particle correlations are used to confront models. Diquark models give good descriptions, except for the on/off Υ(1s) rates. Areas for experimental and theoretical development are indicated. (author)
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.
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.
Lifetime and production rate of beauty baryons from Z decays
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{\
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
Search for CP violation in baryon decays at LHCb
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.
Weak decays of doubly heavy baryons. The 1/2 → 1/2 case
Energy Technology Data Exchange (ETDEWEB)
Wang, Wei; Zhao, Zhen-Xing [Shanghai Jiao Tong University, INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, School of Physics and Astronomy, Shanghai (China); Yu, Fu-Sheng [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China)
2017-11-15
Very recently, the LHCb collaboration has observed in the final state Λ{sub c}{sup +}K{sup -}π{sup +}π{sup +} a resonant structure that is identified as the doubly charmed baryon Ξ{sub cc}{sup ++}. Inspired by this observation, we investigate the weak decays of doubly heavy baryons Ξ{sub cc}{sup ++}, Ξ{sub cc}{sup +}, Ω{sub cc}{sup +}, Ξ{sub bc}{sup (')+}, Ξ{sub bc}{sup (')0}, Ω{sub bc}{sup (')0}, Ξ{sub bb}{sup 0}, Ξ{sub bb}{sup -} and Ω{sub bb}{sup -} and focus on the decays into spin 1/2 baryons in this paper. At the quark level these decay processes are induced by the c → d/s or b → u/c transitions, and the two spectator quarks can be viewed as a scalar or axial vector diquark. We first derive the hadronic form factors for these transitions in the light-front approach and then apply them to predict the partial widths for the semileptonic and nonleptonic decays of doubly heavy baryons. We find that the number of decay channels is sizable and can be examined in future measurements at experimental facilities like LHC, Belle II and CEPC. (orig.)
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 baryon vector current in the combined chiral and 1/Nc expansions
Energy Technology Data Exchange (ETDEWEB)
Flores-Mendieta, Ruben; Goity, Jose L [JLAB
2014-12-01
The baryon vector current is computed at one-loop order in large-Nc baryon chiral perturbation theory, where Nc is the number of colors. Loop graphs with octet and decuplet intermediate states are systematically incorporated into the analysis and the effects of the decuplet-octet mass difference and SU(3) flavor symmetry breaking are accounted for. There are large-Nc cancellations between different one-loop graphs as a consequence of the large-Nc spin-flavor symmetry of QCD baryons. The results are compared against the available experimental data through several fits in order to extract information about the unknown parameters. The large-Nc baryon chiral perturbation theory predictions are in very good agreement both with the expectations from the 1/Nc expansion and with the experimental data. The effect of SU(3) flavor symmetry breaking for the |Delta S|=1 vector current form factors f1(0) results in a reduction by a few percent with respect to the corresponding SU(3) symmetric values.
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.)
International Nuclear Information System (INIS)
Vrhovac, S.B.; Petrovic, Z.Lj.
1995-01-01
Momentum - transfer approximation is applied to momentum and energy balance equations describing reacting particle swarms in gases in crossed electric and magnetic fields. Transport coefficients of charged particles undergoing both inelastic and reactive, non-particle-conserving collisions with a gas of neutral molecules are calculated. Momentum - transfer theory (MTT) has been developed mainly by Robson and collaborators. It has been applied to a single reactive gas and mixtures of reactive gases in electric field only. MTT has also been applied in crossed electric and magnetic fields recently and independently of our work but the reactive collisions were not considered. Consider a swarm of electrons of charge e and mass m moving with velocity rvec v through a neutral gas under the influence of an applied electric rvec E and magnetic rvec B field. The collision processes which we shall investigate are limited to elastic, inelastic and reactive collisions of electrons with gas molecules. Here we interpret reactive collisions as collisions which produce change in number of the swarm particles. Reactive collisions involve creation (ionization by electron impact) or loss (electron attachment) of swarm particles. We consider only single ionization in approximation of the mass ratio m/m 0 0 are masses of electrons and neutral particles, respectively. We assume that the stage of evolution of the swarm is the hydrodynamic limit (HDL). In HDL, the space - time dependence of all properties is carried by the number density n of swarm particles
International Nuclear Information System (INIS)
Perianez, R.; Abril, J.M.; Garcia-Leon, M.
1996-01-01
A 2D four-phase model to study the dispersion of non-conservative radionuclides in tidal waters, in conditions of disequilibrium for ionic exchanges, has been developed. At disequilibrium conditions, ionic exchanges cannot be formulated using distribution coefficients k d . Thus, kinetic transfer coefficients have been used. The model includes ionic exchanges among water and the solid phases (suspended matter and two grain size fractions of sediments), the deposition and resuspension of suspended matter and advective plus diffusive transport. In the second part of this work, which is presented in a separate paper, the model is applied to simulate 226 Ra dispersion, discharged from a fertilizer processing plant, in an estuarine system in the south-west of Spain. (Author)
Directory of Open Access Journals (Sweden)
Branislav Fričovský
2012-12-01
Full Text Available Total geothermal energy potential is estimated for 209 714 TJ per year or 6 650 MWth. Natural conditions define a use of thermalwaters for heat generation only. Accepting proportion of real achievable output of geothermal projects in the non-conservative scenarioat a rate of 1 861 MWth or 13 440 TJ per year, yearly carbon dioxide savings are up to reach 0,357 MtCO2.yr-1 or 12,5 of cumulativeMtCO2 in 35 years. By a contrast, introduction of conservative approach points to increase in a geothermal heat production from 145 to243 TJ per period or 6 944 TJ of cumulative 35 years production, with a real outcome of 0,45 MtCO2 cumulative carbon dioxidesavings, corresponding to yearly real savings from 9,4 .10-3 to 15,8 .10-3 MtCO2.
International Nuclear Information System (INIS)
Velloso, P.A.; Galeao, A.C.
1989-05-01
This paper deals with nonlinear vibrations of pipes subjected to non-conservative loads. Periodic solutions of these problems are determined using a variational approach based on Hamilton's Principle combined with a Fourier series expansion to describe the displacement field time dependence. A finite element model which utilizes Hemite's cubic interpolation for both axial and transversal displacement amplitudes is used. This model is applied to the problem of a pipe subjected to a tangential and a normal follower force. The numerical results obtained with this model are compared with the corespondent solutions determined using a total lagrangian description for the Principle of Virtual Work, coupled with Newmark's step-by-step integration procedure. It is shown that for small to moderate displacement amplitudes the one-term Fourier series approximation compares fairly well with the predicted solution. For large displacements as least a two-term approximation should be utilized [pt
Baryon asymmetry and gravitational waves from pseudoscalar inflation
Jiménez, Daniel; Kamada, Kohei; Schmitz, Kai; Xu, Xun-Jie
2017-12-01
In models of inflation driven by an axion-like pseudoscalar field, the inflaton, a, may couple to the standard model hypercharge via a Chern-Simons-type interaction, Script L ⊃ a/(4Λ) Ftilde F. This coupling results in explosive gauge field production during inflation, especially at its last stage, which has interesting phenomenological consequences: For one thing, the primordial hypermagnetic field is maximally helical. It is thus capable of sourcing the generation of nonzero baryon number, via the standard model chiral anomaly, around the time of electroweak symmetry breaking. For another thing, the gauge field production during inflation feeds back into the primordial tensor power spectrum, leaving an imprint in the stochastic background of gravitational waves (GWs). In this paper, we focus on the correlation between these two phenomena. Working in the approximation of instant reheating, we (1) update the investigation of baryogenesis via hypermagnetic fields from pseudoscalar inflation and (2) examine the corresponding implications for the GW spectrum. We find that successful baryogenesis requires a suppression scale Λ of around Λ ~ 3 × 1017 GeV, which corresponds to a relatively weakly coupled axion. The gauge field production at the end of inflation is then typically accompanied by a peak in the GW spectrum at frequencies in the MHz range or above. The detection of such a peak is out of reach of present-day technology; but in the future, it may serve as a smoking-gun signal for baryogenesis from pseudoscalar inflation. Conversely, models that do yield an observable GW signal suffer from the overproduction of baryon number, unless the reheating temperature is lower than the electroweak scale.
The non-conserved region of MRP is involved in the virulence of Streptococcus suis serotype 2.
Li, Quan; Fu, Yang; Ma, Caifeng; He, Yanan; Yu, Yanfei; Du, Dechao; Yao, Huochun; Lu, Chengping; Zhang, Wei
2017-10-03
Muramidase-released protein (MRP) of Streptococcus suis serotype 2 (SS2) is an important epidemic virulence marker with an unclear role in bacterial infection. To investigate the biologic functions of MRP, 3 mutants named Δmrp, Δmrp domain 1 (Δmrp-d1), and Δmrp domain 2 (Δmrp-d2) were constructed to assess the phenotypic changes between the parental strain and the mutant strains. The results indicated that MRP domain 1 (MRP-D1, the non-conserved region of MRP from a virulent strain, a.a. 242-596) played a critical role in adherence of SS2 to host cells, compared with MRP domain 1* (MRP-D1*, the non-conserved region of MRP from a low virulent strain, a.a. 239-598) or MRP domain 2 (MRP-D2, the conserved region of MRP, a.a. 848-1222). We found that MRP-D1 but not MRP-D2, could bind specifically to fibronectin (FN), factor H (FH), fibrinogen (FG), and immunoglobulin G (IgG). Additionally, we confirmed that mrp-d1 mutation significantly inhibited bacteremia and brain invasion in a mouse infection model. The mrp-d1 mutation also attenuated the intracellular survival of SS2 in RAW246.7 macrophages, shortened the growth ability in pig blood and decreased the virulence of SS2 in BALB/c mice. Furthermore, antiserum against MRP-D1 was found to dramatically impede SS2 survival in pig blood. Finally, immunization with recombinant MRP-D1 efficiently enhanced murine viability after SS2 challenge, indicating its potential use in vaccination strategies. Collectively, these results indicated that MRP-D1 is involved in SS2 virulence and eloquently demonstrate the function of MRP in pathogenesis of infection.
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
Papastergis, Emmanouil; Cattaneo, Andrea; Huang, Shan; Giovanelli, Riccardo; Haynes, Martha P.
2012-01-01
We use both an HI-selected and an optically-selected galaxy sample to directly measure the abundance of galaxies as a function of their "baryonic" mass (stars + atomic gas). Stellar masses are calculated based on optical data from the Sloan Digital Sky Survey (SDSS) and atomic gas masses are
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.
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.)
Dynamical twisted mass fermions and baryon spectroscopy
International Nuclear Information System (INIS)
Drach, V.
2010-06-01
The aim of this work is an ab initio computation of the baryon masses starting from quantum chromodynamics (QCD). This theory describes the interaction between quarks and gluons and has been established at high energy thanks to one of its fundamental properties: the asymptotic freedom. This property predicts that the running coupling constant tends to zero at high energy and thus that perturbative expansions in the coupling constant are justified in this regime. On the contrary the low energy dynamics can only be understood in terms of a non perturbative approach. To date, the only known method that allows the computation of observables in this regime together with a control of its systematic effects is called lattice QCD. It consists in formulating the theory on an Euclidean space-time and to evaluating numerically suitable functional integrals. First chapter is an introduction to the QCD in the continuum and on a discrete space time. The chapter 2 describes the formalism of maximally twisted fermions used in the European Twisted Mass (ETM) collaboration. The chapter 3 deals with the techniques needed to build hadronic correlator starting from gauge configuration. We then discuss how we determine hadron masses and their statistical errors. The numerical estimation of functional integral is explained in chapter 4. It is stressed that it requires sophisticated algorithm and massive parallel computing on Blue-Gene type architecture. Gauge configuration production is an important part of the work realized during my Ph.D. Chapter 5 is a critical review on chiral perturbation theory in the baryon sector. The two last chapter are devoted to the analysis in the light and strange baryon sector. Systematics and chiral extrapolation are extensively discussed. (author)
Non-conservation of parity in fission of 234U, 236U and 240Pu nuclei
International Nuclear Information System (INIS)
Danilyan, G.V.; Vodennikov, B.D.; Dronyaev, V.P.; Novitskij, V.V.; Pavlov, V.S.; Borovlev, S.P.
1980-01-01
Targets, which contained approximately 100 μg.cm -2 fissionable material placed on both sides of an aluminium backing and were 0.1-0.15 mm wide, were arranged in a vacuum chamber along the axis of the neutron beam. Silicon surface-barrier detectors were arranged on each side of the target to detect fission fragments emitted by the target either in the direction of neutron polarization or away from it, depending on the direction of neutron-beam polarization at the moment of fragment detection. The direction of polarization could be reversed once per second; however, it was reversed not regularly but stochastically. An electronic circuit separated out pulses from light and heavy fragments and channelled them into scaling circuits corresponding to the two opposing directions of polarization. After each measurement cycle a computer connected on line with the experiment calculated the asymmetry in the number of light and heavy fragments counted by a given detector when the direction of neutron beam polarization was reversed. The measurement cycle lasted approximately 17 min, during which time the direction of polarization was reversed on average approximately 600 times. Measurements on a polarized beam alternated with measurements on a depolarized beam. Control measurements excluded the possibility of instruments affecting the results
Critical opalescence in baryonic QCD matter.
Antoniou, N G; Diakonos, F K; Kapoyannis, A S; Kousouris, K S
2006-07-21
We show that critical opalescence, a clear signature of second-order phase transition in conventional matter, manifests itself as critical intermittency in QCD matter produced in experiments with nuclei. This behavior is revealed in transverse momentum spectra as a pattern of power laws in factorial moments, to all orders, associated with baryon production. This phenomenon together with a similar effect in the isoscalar sector of pions (sigma mode) provide us with a set of observables associated with the search for the QCD critical point in experiments with nuclei at high energies.
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.
STRANGE BARYONIC MATTER AND KAON CONDENSATION
Czech Academy of Sciences Publication Activity Database
Gazda, Daniel; Friedman, E.; Gal, A.; Mareš, Jiří
2011-01-01
Roč. 26, 3-4 (2011), s. 567-569 ISSN 0217-751X. [11th International Workshop on Meson Production, Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA ČR GA202/09/1441 Institutional research plan: CEZ:AV0Z10480505 Keywords : (K)over-bar-nuclear bound states * strange baryonic matter * kaon condensation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.053, year: 2011
Parity doubling in the baryon string model
International Nuclear Information System (INIS)
Khokhlachev, S.B.
1990-01-01
The nature of parity doubling of baryon states with non-zero angular momentum is considered. The idea of explaining this phenomenon lies in the fact that the rotation of the gluon string leads to a centrifugal potential for quarks. The quarks on the string form a quark-diquark system. Quark tunneling from one end of the string to the other is not probable for systems with large angular momentum due to a large centrifugal potential, and the smallness of the underbarrier transition amplitude explains the small mass difference of the states with opposite parity. (orig.)
Critical Opalescence in Baryonic QCD Matter
Antoniou, N. G.; Diakonos, F. K.; Kapoyannis, A. S.; Kousouris, K. S.
2006-07-01
We show that critical opalescence, a clear signature of second-order phase transition in conventional matter, manifests itself as critical intermittency in QCD matter produced in experiments with nuclei. This behavior is revealed in transverse momentum spectra as a pattern of power laws in factorial moments, to all orders, associated with baryon production. This phenomenon together with a similar effect in the isoscalar sector of pions (sigma mode) provide us with a set of observables associated with the search for the QCD critical point in experiments with nuclei at high energies.
Critical Opalescence in Baryonic QCD Matter
International Nuclear Information System (INIS)
Antoniou, N. G.; Diakonos, F. K.; Kapoyannis, A. S.; Kousouris, K. S.
2006-01-01
We show that critical opalescence, a clear signature of second-order phase transition in conventional matter, manifests itself as critical intermittency in QCD matter produced in experiments with nuclei. This behavior is revealed in transverse momentum spectra as a pattern of power laws in factorial moments, to all orders, associated with baryon production. This phenomenon together with a similar effect in the isoscalar sector of pions (sigma mode) provide us with a set of observables associated with the search for the QCD critical point in experiments with nuclei at high energies
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.
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)
Galaxy Formation by Cosmic Strings and Cooling of Baryonic Matter
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.
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
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.
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
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.
Search for strange baryon electric dipole moment at LHCb
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.
Another baryon miracle? Testing solutions to the `missing dwarfs' problem
Trujillo-Gomez, Sebastian; Schneider, Aurel; Papastergis, Emmanouil; Reed, Darren S.; Lake, George
2018-04-01
The dearth of dwarf galaxies in the local Universe is hard to reconcile with the large number of low-mass haloes expected within the concordance Λ cold dark matter (ΛCDM) paradigm. In this paper, we perform a systematic evaluation of the uncertainties affecting the measurement of dark matter halo abundance using galaxy kinematics. Using a large sample of dwarf galaxies with spatially resolved kinematics, we derive a correction to obtain the abundance of galaxies as a function of maximum circular velocity - a direct probe of halo mass - from the line-of-sight velocity function in the Local Volume. This method provides a direct means of comparing the predictions of theoretical models and simulations (including non-standard cosmologies and novel galaxy formation physics) to the observational constraints. The new `galactic Vmax' function is steeper than the line-of-sight velocity function but still shallower than the theoretical CDM expectation, implying that unaccounted baryonic physics may be necessary to reduce the predicted abundance of galaxies. Using the galactic Vmax function, we investigate the theoretical effects of feedback-powered outflows and photoevaporation of gas due to reionization. At the 3σ confidence level, we find that feedback and reionization are not effective enough to reconcile the disagreement. In the case of maximum baryonic effects, the theoretical prediction still deviates significantly from the observations for Vmax < 60 km s-1. CDM predicts at least 1.8 times more galaxies with Vmax = 50 km s-1 and 2.5 times more than observed at 30 km s-1. Recent hydrodynamic simulations seem to resolve the discrepancy but disagree with the properties of observed galaxies with spatially resolved kinematics. This abundance problem might point to the need to modify cosmological predictions at small scales.
Efficient construction of mock catalogs for baryon acoustic oscillation surveys
International Nuclear Information System (INIS)
Sunayama, Tomomi; Padmanabhan, Nikhil; Heitmann, Katrin; Habib, Salman; Rangel, Esteban
2016-01-01
Precision measurements of the large scale structure of the Universe require large numbers of high fidelity mock catalogs to accurately assess, and account for, the presence of systematic effects. We introduce and test a scheme for generating mock catalogs rapidly using suitably derated N-body simulations. Our aim is to reproduce the large scale structure and the gross properties of dark matter halos with high accuracy, while sacrificing the details of the halo's internal structure. By adjusting global and local time-steps in an N-body code, we demonstrate that we recover halo masses to better than 0.5% and the power spectrum to better than 1% both in real and redshift space for k =1 h Mpc −1 , while requiring a factor of 4 less CPU time. We also calibrate the redshift spacing of outputs required to generate simulated light cones. We find that outputs separated by Δ z =0.05 allow us to interpolate particle positions and velocities to reproduce the real and redshift space power spectra to better than 1% (out to k =1 h Mpc −1 ). We apply these ideas to generate a suite of simulations spanning a range of cosmologies, motivated by the Baryon Oscillation Spectroscopic Survey (BOSS) but broadly applicable to future large scale structure surveys including eBOSS and DESI. As an initial demonstration of the utility of such simulations, we calibrate the shift in the baryonic acoustic oscillation peak position as a function of galaxy bias with higher precision than has been possible so far. This paper also serves to document the simulations, which we make publicly available.
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
The Compressed Baryonic Matter Experiment at FAIR
International Nuclear Information System (INIS)
Heuser, Johann M.
2013-01-01
The Compressed Baryonic Matter (CBM) experiment will explore the phase diagram of strongly interacting matter in the region of high net baryon densities. The experiment is being laid out for nuclear collision rates from 0.1 to 10 MHz to access a unique wide spectrum of probes, including rarest particles like hadrons containing charm quarks, or multi-strange hyperons. The physics programme will be performed with ion beams of energies up to 45 GeV/nucleon. Those will be delivered by the SIS-300 synchrotron at the completed FAIR accelerator complex. Parts of the research programme can already be addressed with the SIS-100 synchrotron at the start of FAIR operation in 2018. The initial energy range of up to 11 GeV/nucleon for heavy nuclei, 14 GeV/nucleon for light nuclei, and 29 GeV for protons, allows addressing the equation of state of compressed nuclear matter, the properties of hadrons in a dense medium, the production and propagation of charm near the production threshold, and exploring the third, strange dimension of the nuclide chart. In this article we summarize the CBM physics programme, the preparation of the detector, and give an outline of the recently begun construction of the Facility for Antiproton and Ion Research
The Compressed Baryonic Matter experiment at FAIR
Directory of Open Access Journals (Sweden)
Höhne Claudia
2018-01-01
Full Text Available The CBM experiment will investigate highly compressed baryonic matter created in A+A collisions at the new FAIR research center. With a beam energy range up to 11 AGeV for the heaviest nuclei at the SIS 100 accelerator, CBM will investigate the QCD phase diagram in the intermediate range, i.e. at moderate temperatures but high net-baryon densities. This intermediate range of the QCD phase diagram is of particular interest, because a first order phase transition ending in a critical point and possibly new highdensity phases of strongly interacting matter are expected. In this range of the QCD phase diagram only exploratory measurements have been performed so far. CBM, as a next generation, high-luminosity experiment, will substantially improve our knowledge of matter created in this region of the QCD phase diagram and characterize its properties by measuring rare probes such as multi-strange hyperons, dileptons or charm, but also with event-by-event fluctuations of conserved quantities, and collective flow of identified particles. The experimental preparations with special focus on hadronic observables and strangeness is presented in terms of detector development, feasibility studies and fast track reconstruction. Preparations are progressing well such that CBM will be ready with FAIR start. As quite some detectors are ready before, they will be used as upgrades or extensions of already running experiments allowing for a rich physics program prior to FAIR start.
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
Finite temperature system of strongly interacting baryons
International Nuclear Information System (INIS)
Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.
1976-07-01
A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc 2 /k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10 11 0 K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light
Analysis of the photocouplings of baryon resonances
Energy Technology Data Exchange (ETDEWEB)
Bando, M; Toya, M [Kyoto Univ. (Japan). Dept. of Physics; Sugimoto, Hiroshi
1978-02-01
The typical features of the photocouplings of the 70 L=1 and 56 L=2 baryon resonances are discussed in view of the recently reported experimental data. It is emphasized that our relativistic quark model is very convenient for the phenomenological study on the photocouplings and also is suitable for a simple physical interpretation. The phenomenological analysis of the photocoupling data based on our model concludes that the transition from the quark state (jsup(P)=1/2/sup +/, lambda=1/2) to (j=L + 1/2, lambda=3/2) is dominant in the photo-transitions from nucleons to the excited baryons in both cases L=1 and 2. Our result implies the non-negligible magnitude of the value of delta L sub(z)=2 term. The experimental data on A sub(1/2)sup(p)(P/sub 13/) and A sub(3/2)sup(p)(P/sub 13/) is crucial to confirm the strength of delta L sub(z)=2 term.
Finite temperature system of strongly interacting baryons
Energy Technology Data Exchange (ETDEWEB)
Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.
1976-07-01
A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc/sup 2//k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10/sup 11/ /sup 0/K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light.
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
Masses and Regge trajectories of triply heavy Ω{sub ccc} and Ω{sub bbb} baryons
Energy Technology Data Exchange (ETDEWEB)
Shah, Zalak; Rai, Ajay Kumar [Sardar Vallabhbhai National Institute of Technology, Department of Applied Physics, Surat, Gujarat (India)
2017-10-15
The excited state masses of triply charm and triply bottom Ω baryons are exhibited in the present study. The masses are computed for 1S-5S, 1P-5P, 1D-4D and 1F-2F states in the Hypercentral Constituent Quark Model (hCQM) with the hyper Coulomb plus linear potential. The triply charm/bottom baryon masses are experimentally unknown so that the Regge trajectories are plotted using computed masses to assign the quantum numbers of these unknown states. (orig.)
SU(3) chiral symmetry for baryons
International Nuclear Information System (INIS)
Dmitrasinovic, V.
2011-01-01
Three-quark nucleon interpolating fields in QCD have well-defined SU L (3)xSU R (3) and U A (1) chiral transformation properties, viz. [(6,3)+(3,6)], [(3,3-bar)+(3-bar,3)], [(8,1)+(1,8)] and their 'mirror' images. It has been shown (phenomenologically) in Ref. [2] that mixing of the [(6,3)+(3,6)] chiral multiplet with one ordinary ('naive') and one 'mirror' field belonging to the [(3,3-bar)+(3-bar,3)], [(8,1)+(1,8)] multiplets can be used to fit the values of the isovector (g A (3) ) and the flavor-singlet (isoscalar) axial coupling (g A (0) ) of the nucleon and then predict the axial F and D coefficients, or vice versa, in reasonable agreement with experiment. In an attempt to derive such mixing from an effective Lagrangian, we construct all SU L (3)xSU R (3) chirally invariant non-derivative one-meson-baryon interactions and then calculate the mixing angles in terms of baryons' masses. It turns out that there are (strong) selection rules: for example, there is only one non-derivative chirally symmetric interaction between J 1/2 fields belonging to the [(6,3)+(3,6)] and the [(3,3-bar)+(3-bar,3)] chiral multiplets, that is also U A (1) symmetric. We also study the chiral interactions of the [(3,3-bar)+(3-bar,3)] and [(8,1)+(1,8)] nucleon fields. Again, there are selection rules that allow only one off-diagonal non-derivative chiral SU L (3)xSU R (3) interaction of this type, that also explicitly breaks the U A (1) symmetry. We use this interaction to calculate the corresponding mixing angles in terms of baryon masses and fit two lowest lying observed nucleon (resonance) masses, thus predicting the third (J = 1/2, I = 3/2)Δ resonance, as well as one or two flavor-singlet Λ hyperon(s), depending on the type of mixing. The effective chiral Lagrangians derived here may be applied to high density matter calculations.
Evidence for non-conservative current-induced forces in the breaking of Au and Pt atomic chains.
Sabater, Carlos; Untiedt, Carlos; van Ruitenbeek, Jan M
2015-01-01
This experimental work aims at probing current-induced forces at the atomic scale. Specifically it addresses predictions in recent work regarding the appearance of run-away modes as a result of a combined effect of the non-conservative wind force and a 'Berry force'. The systems we consider here are atomic chains of Au and Pt atoms, for which we investigate the distribution of break down voltage values. We observe two distinct modes of breaking for Au atomic chains. The breaking at high voltage appears to behave as expected for regular break down by thermal excitation due to Joule heating. However, there is a low-voltage breaking mode that has characteristics expected for the mechanism of current-induced forces. Although a full comparison would require more detailed information on the individual atomic configurations, the systems we consider are very similar to those considered in recent model calculations and the comparison between experiment and theory is very encouraging for the interpretation we propose.
Evidence for non-conservative current-induced forces in the breaking of Au and Pt atomic chains
Directory of Open Access Journals (Sweden)
Carlos Sabater
2015-12-01
Full Text Available This experimental work aims at probing current-induced forces at the atomic scale. Specifically it addresses predictions in recent work regarding the appearance of run-away modes as a result of a combined effect of the non-conservative wind force and a ‘Berry force’. The systems we consider here are atomic chains of Au and Pt atoms, for which we investigate the distribution of break down voltage values. We observe two distinct modes of breaking for Au atomic chains. The breaking at high voltage appears to behave as expected for regular break down by thermal excitation due to Joule heating. However, there is a low-voltage breaking mode that has characteristics expected for the mechanism of current-induced forces. Although a full comparison would require more detailed information on the individual atomic configurations, the systems we consider are very similar to those considered in recent model calculations and the comparison between experiment and theory is very encouraging for the interpretation we propose.
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.
Leptogenesis and gravity: Baryon asymmetry without decays
Directory of Open Access Journals (Sweden)
J.I. McDonald
2017-03-01
Full Text Available A popular class of theories attributes the matter-antimatter asymmetry of the Universe to CP-violating decays of super-heavy BSM particles in the Early Universe. Recently, we discovered a new source of leptogenesis in these models, namely that the same Yukawa phases which provide the CP violation for decays, combined with curved-spacetime loop effects, lead to an entirely new gravitational mechanism for generating an asymmetry, driven by the expansion of the Universe and independent of the departure of the heavy particles from equilibrium. In this Letter, we build on previous work by analysing the full Boltzmann equation, exploring the full parameter space of the theory and studying the time-evolution of the asymmetry. Remarkably, we find regions of parameter space where decays play no part at all, and where the baryon asymmetry of the Universe is determined solely by gravitational effects.
Reconstructing baryon oscillations: A Lagrangian theory perspective
International Nuclear Information System (INIS)
Padmanabhan, Nikhil; White, Martin; Cohn, J. D.
2009-01-01
Recently Eisenstein and collaborators introduced a method to 'reconstruct' the linear power spectrum from a nonlinearly evolved galaxy distribution in order to improve precision in measurements of baryon acoustic oscillations. We reformulate this method within the Lagrangian picture of structure formation, to better understand what such a method does, and what the resulting power spectra are. We show that reconstruction does not reproduce the linear density field, at second order. We however show that it does reduce the damping of the oscillations due to nonlinear structure formation, explaining the improvements seen in simulations. Our results suggest that the reconstructed power spectrum is potentially better modeled as the sum of three different power spectra, each dominating over different wavelength ranges and with different nonlinear damping terms. Finally, we also show that reconstruction reduces the mode-coupling term in the power spectrum, explaining why miscalibrations of the acoustic scale are reduced when one considers the reconstructed power spectrum.
Strange baryons with two heavy quarks
Karliner, Marek; Rosner, Jonathan L.
2018-05-01
The LHCb Experiment at CERN has observed a doubly-charmed baryon Ξcc ++=c c u with a mass of 3621.40 ±0.78 MeV , consistent with many predictions. We use the same methods that led us to predict M (Ξc c,JP=1 /2+)=3627 ±12 MeV and M (Ξcc *,JP=3 /2+)=3690 ±12 MeV to predict M (Ωcc +,JP=1 /2+)=3692 ±16 MeV and M (Ωcc *,JP=3 /2+)=3756 ±16 MeV . Production and decay are discussed briefly, and predictions for M (Ωb c) and M (Ωb b) are included.
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
Observation of excited $\\Lambda^0_b$ baryons
INSPIRE-00258707; Abellan Beteta, C; Adametz, A; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves Jr, A A; Amato, S; Amhis, Y; Anderson, J; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bates, A; Bauer, C; Bauer, Th; Bay, A; Beddow, J; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Benayoun, M; Bencivenni, G; Benson, S; Benton, J; Bernet, R; Bettler, M -O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blanks, C; Blouw, J; Blusk, S; Bobrov, A; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Büchler-Germann, A; Burducea, I; Bursche, A; Buytaert, J; Cadeddu, S; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carson, L; Carvalho Akiba, K; Casse, G; Cattaneo, M; Cauet, Ch; Charles, M; Charpentier, Ph; Chen, P; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coca, C; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Corti, G; Couturier, B; Cowan, G A; Craik, D; Currie, R; D'Ambrosio, C; David, P; David, P N Y; De Bonis, I; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Simone, P; Decamp, D; Deckenhoff, M; Degaudenzi, H; Del Buono, L; Deplano, C; Derkach, D; Deschamps, O; Dettori, F; Dickens, J; Dijkstra, H; Diniz Batista, P; Domingo Bonal, F; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisele, F; Eisenhardt, S; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Elsby, D; Esperante Pereira, D; Falabella, A; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Fernandez Albor, V; Ferro-Luzzi, M; Filippov, S; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Furcas, S; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garnier, J-C; Garofoli, J; Garra Tico, J; Garrido, L; Gascon, D; Gaspar, C; Gauld, R; Gauvin, N; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hampson, T; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Harrison, P F; Hartmann, T; He, J; Heijne, V; Hennessy, K; Henrard, P; Hernando Morata, J A; van Herwijnen, E; Hicks, E; Hoballah, M; Hopchev, P; Hulsbergen, W; Hunt, P; Huse, T; Huston, R S; Hutchcroft, D; Hynds, D; Iakovenko, V; Ilten, P; Imong, J; Jacobsson, R; Jaeger, A; Jahjah Hussein, M; Jans, E; Jansen, F; Jaton, P; Jean-Marie, B; Jing, F; John, M; Johnson, D; Jones, C R; Jost, B; Kaballo, M; Kandybei, S; Karacson, M; Karbach, T M; Keaveney, J; Kenyon, I R; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kim, Y M; Knecht, M; Kochebina, O; Komarov, I; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kruzelecki, K; Kucharczyk, M; Kudryavtsev, V; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J -P; Lefèvre, R; Leflat, A; Lefrançois, J; Leroy, O; Lesiak, T; Li, L; Li, Y; Li Gioi, L; Lieng, M; Liles, M; Lindner, R; Linn, C; Liu, B; Liu, G; von Loeben, J; Lopes, J H; Lopez Asamar, E; Lopez-March, N; Lu, H; Luisier, J; Mac Raighne, A; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Magnin, J; Malde, S; Mamunur, R M D; Manca, G; Mancinelli, G; Mangiafave, N; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martin, L; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Massafferri, A; Mathe, Z; Matteuzzi, C; Matveev, M; Maurice, E; Maynard, B; Mazurov, A; McCarthy, J; McGregor, G; McNulty, R; Meissner, M; Merk, M; Merkel, J; Milanes, D A; Minard, M -N; Molina Rodriguez, J; Monteil, S; Moran, D; Morawski, P; Mountain, R; Mous, I; Muheim, F; Müller, K; Muresan, R; Muryn, B; Muster, B; Mylroie-Smith, J; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neufeld, N; Nguyen, A D; Nguyen-Mau, C; Nicol, M; Niess, V; Nikitin, N; Nikodem, T; Nomerotski, A; Novoselov, A; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Otalora Goicochea, J M; Owen, P; Pal, B K; Palacios, J; Palano, A; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrick, G N; Patrignani, C; Pavel-Nicorescu, C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Perez Trigo, E; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pessina, G; Petrolini, A; Phan, A; Picatoste Olloqui, E; Pie Valls, B; Pietrzyk, B; Pilař, T; Pinci, D; Plackett, R; Playfer, S; Plo Casasus, M; Polci, F; Polok, G; Poluektov, A; Polycarpo, E; Popov, D; Popovici, B; Potterat, C; Powell, A; Prisciandaro, J; Pugatch, V; Puig Navarro, A; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Ricciardi, S; Richards, A; Rinnert, K; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodrigues, F; Rodriguez Perez, P; Rogers, G J; Roiser, S; Romanovsky, V; Rosello, M; Rouvinet, J; Ruf, T; Ruiz, H; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salzmann, C; Sanmartin Sedes, B; Sannino, M; Santacesaria, R; Santamarina Rios, C; Santinelli, R; Santovetti, E; Sapunov, M; Sarti, A; Satriano, C; Satta, A; Savrie, M; Savrina, D; Schaack, P; Schiller, M; Schindler, H; Schleich, S; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M -H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Senderowska, K; Sepp, I; Serra, N; Serrano, J; Seyfert, P; Shapkin, M; Shapoval, I; Shatalov, P; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, O; Shevchenko, V; Shires, A; Silva Coutinho, R; Skwarnicki, T; Smith, N A; Smith, E; Smith, M; Sobczak, K; Soler, F J P; Solomin, A; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Stagni, F; Stahl, S; Steinkamp, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Subbiah, V K; Swientek, S; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teklishyn, M; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tsaregorodtsev, A; Tuning, N; Ubeda Garcia, M; Ukleja, A; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Vesterinen, M; Viaud, B; Videau, I; Vieira, D; Vilasis-Cardona, X; Visniakov, J; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; Waldi, R; Wallace, R; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Webber, A D; Websdale, D; Whitehead, M; Wicht, J; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Witzeling, W; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, F; Xing, Z; Yang, Z; Young, R; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhong, L; Zvyagin, A
2012-01-01
Using $pp$ collision data corresponding to 1.0~fb^{-1} integrated luminosity collected by the LHCb detector, two narrow states are observed in the $\\Lambda_b^0\\pi^+\\pi^-$ spectrum with masses $5911.95\\pm 0.12(\\mbox{stat})\\pm 0.03(\\mbox{syst})\\pm 0.66(\\Lambda_b^0\\mbox{ mass})$ MeV/$c^2$ and $5919.76\\pm 0.07(\\mbox{stat})\\pm 0.02(\\mbox{syst})\\pm 0.66(\\Lambda_b^0\\mbox{ mass})$ MeV/$c^2$. The significances of the observations are 4.9 and 10.1 standard deviations, respectively. These states are interpreted as the orbitally-excited $\\Lambda_b^0$ baryons, $\\Lambda_b^{*0}(5912)$ and $\\Lambda_b^{*0}(5920)$.
Shedding light on baryonic dark matter
Silk, Joseph
1991-01-01
Halo dark matter, if it is baryonic, may plausibly consist of compact stellar remnants. Jeans mass clouds containing 10 to the 6th to 10 to the 8th solar masses could have efficiently formed stars in the early universe and could plausibly have generated, for a suitably top-heavy stellar initial mass function, a high abundance of neutron stars as well as a small admixture of long-lived low mass stars. Within the resulting clusters of dark remnants, which eventually are tidally disrupted when halos eventually form, captures of neutron stars by nondegenerate stars resulted in formation of close binaries. These evolve to produce, by the present epoch, an observable X-ray signal associated with dark matter aggregations in galaxy cluster cores.
Chiral analysis of quenched baryon masses
International Nuclear Information System (INIS)
Young, R.D.; Leinweber, D.B.; Thomas, A.W.; Wright, S. V.
2002-01-01
We extend to quenched QCD an earlier investigation of the chiral structure of the masses of the nucleon and the delta in lattice simulations of full QCD. Even after including the meson-loop self-energies which give rise to the leading and next-to-leading nonanalytic behavior (and hence the most rapid variation in the region of light quark mass), we find surprisingly little curvature in the quenched case. Replacing these meson-loop self-energies by the corresponding terms in full QCD yields a remarkable level of agreement with the results of the full QCD simulations. This comparison leads to a very good understanding of the origins of the mass splitting between these baryons
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)
Isospin breaking in octet baryon mass splittings
Energy Technology Data Exchange (ETDEWEB)
Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Najjar, J. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo (Japan); Pleiter, D. [Forschungszentrum Juelich (Germany). Juelich Supercomputer Centre; 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
Using an SU(3) flavour symmetry breaking expansion in the quark mass, we determine the QCD component of the nucleon, Sigma and Xi mass splittings of the baryon octet due to up-down (and strange) quark mass differences in terms of the kaon mass splitting. Provided the average quark mass is kept constant, the expansion coefficients in our procedure can be determined from computationally cheaper simulations with mass degenerate sea quarks and partially quenched valence quarks. Both the linear and quadratic terms in the SU(3) flavour symmetry breaking expansion are considered; it is found that the quadratic terms only change the result by a few percent, indicating that the expansion is highly convergent.
Equivalence principle and the baryon acoustic peak
Baldauf, Tobias; Mirbabayi, Mehrdad; Simonović, Marko; Zaldarriaga, Matias
2015-08-01
We study the dominant effect of a long wavelength density perturbation δ (λL) on short distance physics. In the nonrelativistic limit, the result is a uniform acceleration, fixed by the equivalence principle, and typically has no effect on statistical averages due to translational invariance. This same reasoning has been formalized to obtain a "consistency condition" on the cosmological correlation functions. In the presence of a feature, such as the acoustic peak at ℓBAO, this naive expectation breaks down for λLexplicitly applied to the one-loop calculation of the power spectrum. Finally, the success of baryon acoustic oscillation reconstruction schemes is argued to be another empirical evidence for the validity of the results.
Leptogenesis and gravity: Baryon asymmetry without decays
Energy Technology Data Exchange (ETDEWEB)
McDonald, J.I., E-mail: pymcdonald@swansea.ac.uk; Shore, G.M., E-mail: g.m.shore@swansea.ac.uk
2017-03-10
A popular class of theories attributes the matter-antimatter asymmetry of the Universe to CP-violating decays of super-heavy BSM particles in the Early Universe. Recently, we discovered a new source of leptogenesis in these models, namely that the same Yukawa phases which provide the CP violation for decays, combined with curved-spacetime loop effects, lead to an entirely new gravitational mechanism for generating an asymmetry, driven by the expansion of the Universe and independent of the departure of the heavy particles from equilibrium. In this Letter, we build on previous work by analysing the full Boltzmann equation, exploring the full parameter space of the theory and studying the time-evolution of the asymmetry. Remarkably, we find regions of parameter space where decays play no part at all, and where the baryon asymmetry of the Universe is determined solely by gravitational effects.
Cosmic ray antimatter and baryon symmetric cosmology
Stecker, F. W.; Protheroe, R. J.; Kazanas, D.
1982-01-01
The relative merits and difficulties of the primary and secondary origin hypotheses for the observed cosmic-ray antiprotons, including the new low-energy measurement of Buffington, et al. We conclude that the cosmic-ray antiproton data may be evidence for antimatter galaxies and baryon symmetric cosmology. The present bar P data are consistent with a primary extragalactic component having /p=/equiv 1+/- 3.2/0.7x10 = to the -4 independent of energy. We propose that the primary extragalactic cosmic ray antiprotons are most likely from active galaxies and that expected disintegration of bar alpha/alpha ban alpha/alpha. We further predict a value for ban alpha/alpha =/equiv 10 to the -5, within range of future cosmic ray detectors.
General solution of superconvergent sum rules for scattering of I=1 reggeons on baryons
International Nuclear Information System (INIS)
Grigoryan, A.A.; Khachatryan, G.N.
1986-01-01
Superconvergent sum rules for reggeon-particle scattering are applied to scattering of reggeons α i (i=π, ρ, A 2 ) with isospin I=1 on baryons with strangeness S=-1. The saturation scheme of these sum rules is determined on the basis of experimental data. Two series of baryon resonances with arbitrary isospins I and spins J=I+1/2 and J=I-1/2 are predicted. A general solution for vertices of interaction of these resonances with α i is found. Predictions for coupling vertices B α i B'(B, B'=Λ, Σ, Σ * ) agree well with the experiment. It is shown that the condition of sum rules saturation by minimal number of resonances brings to saturation schemes resulting from experimental data. A general solution of sum rules for scattering of α i reggeons on Ξ and Ω hyperons is analyzed
The Compressed Baryonic Matter Experiment at FAIR
Directory of Open Access Journals (Sweden)
Heuser J.M.
2011-04-01
Full Text Available The Compressed Baryonic Matter (CBM experiment is being planned at the international research centre FAIR, under realization next to the GSI laboratory in Darmstadt, Germany. Its physics programme addresses the QCD phase diagram in the region of highest net baryon densities. Of particular interest are the expected first order phase transition from partonic to hadronic matter, ending in a critical point, and modifications of hadron properties in the dense medium as a signal of chiral symmetry restoration. Laid out as a fixed-target experiment at the synchrotrons SIS-100/SIS-300, providing magnetic bending power of 100 and 300 T/m, the CBM detector will record both proton-nucleus and nucleus-nucleus collisions at beam energies up to 45A GeV. Hadronic, leptonic and photonic observables have to be measured with large acceptance. The nuclear interaction rates will reach up to 10 MHz to measure extremely rare probes like charm near threshold. Two versions of the experiment are being studied, optimized for either electron-hadron or muon identification, combined with silicon detector based charged-particle tracking and micro-vertex detection. The research programme will start at SIS-100 with ion beams between 2 and 11A GeV, and protons up to energies of 29 GeV using the HADES detector and an initial configuration of the CBM experiment. The CBM physics requires the development of novel detector systems, trigger and data acquisition concepts as well as innovative real-time reconstruction techniques. Progress with feasibility studies of the experiment and the development of its detector systems are discussed.
Compressed baryonic matter experiment at FAIR
Directory of Open Access Journals (Sweden)
Jürgen Eschke
2012-02-01
Full Text Available The Compressed Baryonic Matter (CBM experiment is being planned at the Facility for Antiproton and Ion Research (FAIR, under realization next to the GSI laboratory in Darmstadt, Germany. Its physics programme addresses the QCD phase diagram in the region of highest net baryon densities. Of particular interest are the expected first order phase transition from partonic to hadronic matter, ending in a critical point, and modifcations of hadron properties in the dense medium as a signal of chiral symmetry restoration. Laid out as a fixed-target experiment at the synchrotrons SIS-100/SIS-300, providing magnetic bending power of 100 and 300 T/Fm, the CBM detector will record both proton-nucleus and nucleus-nucleus collisions at beam energies up to 45 AGeV. Hadronic, leptonic and photonic observables will be measured in a large acceptance. The nuclear interaction rates will reach up to 10 MHz to measure extremely rare probes like charm near threshold. This requires the development of novel detector systems, trigger and data acquisition concepts as well as in- novative real-time reconstruction techniques. A key observable of the physics program is a precise measurement of lowmass vector mesons and charmonium in their leptonic decay channel. In CBM, electrons will be identified using a gaseous RICH detector combined with several TRD detectors positioned after a system of silicon tracking stations which are located inside a magnetic dipole field. The concept of the RICH detector, results on R & D as well as feasibility studies and invariant mass distributions of charmonium will be discussed.
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.
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
Modelling baryonic effects on galaxy cluster mass profiles
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.
An investigation of triply heavy baryon production at hadron colliders
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.
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.
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
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)
Scattering of decuplet baryons in chiral effective field theory
Energy Technology Data Exchange (ETDEWEB)
Haidenbauer, J. [Institut fuer Kernphysik, Institute for Advanced Simulation and Juelich Center for Hadron Physics, Juelich (Germany); Petschauer, S.; Kaiser, N.; Weise, W. [Technische Universitaet Muenchen, Physik Department, Garching (Germany); Meissner, Ulf G. [Institut fuer Kernphysik, Institute for Advanced Simulation and Juelich Center for Hadron Physics, Juelich (Germany); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany)
2017-11-15
A formalism for treating the scattering of decuplet baryons in chiral effective field theory is developed. The minimal Lagrangian and potentials in leading-order SU(3) chiral effective field theory for the interactions of octet baryons (B) and decuplet baryons (D) for the transitions BB → BB, BB <-> DB, DB → DB, BB <-> DD, DB <-> DD, and DD → DD are provided. As an application of the formalism we compare with results from lattice QCD simulations for ΩΩ and NΩ scattering. Implications of our results pertinent to the quest for dibaryons are discussed. (orig.)
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
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.
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
The Evolution of Galaxies by the Incompatibility between Dark Matter and Baryonic Matter
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...
Doubly charmed baryon production in heavy ion collisions
Yao, Xiaojun; Müller, Berndt
2018-04-01
We give an estimate of Ξcc ++ production rate and transverse momentum spectra in relativistic heavy ion collisions. We use Boltzmann transport equations to describe the dynamical evolution of charm quarks and diquarks inside quark-gluon plasma. In-medium formation and dissociation rates of charm diquarks are calculated from potential nonrelativistic QCD for the diquark sector. We solve the transport equations by Monte Carlo simulations. For 2.76 TeV Pb-Pb collisions with 0-10% centrality, the number of Ξcc ++ produced in the transverse momentum range 0-5 GeV and rapidity from -1 to 1 is roughly 0.02 per collision. We repeat the calculation with a melting temperature 250 MeV above which no diquarks can be formed. The number of Ξcc ++ produced in the same kinematic region is about 0.0125 per collision. We discuss how to study diquarks at finite temperature on a lattice and construct the antitriplet free energy in a gauge invariant but path dependent way. We also comment on extensions of the calculation to other doubly heavy baryons and doubly heavy tetraquarks and the feasibility of experimental measurements.
Glueballs, hermaphrodites and QCD problems for baryon spectroscopy
International Nuclear Information System (INIS)
Close, F.E.
1981-08-01
Spin-orbit splittings in baryon spectroscopy are examined with relevance to QCD: successes and failures are discussed. Claims to have seen glueballs are evaluated and the possibility of hermaphrodites-states containing quarks and glue - is mentioned. (author)
The baryon asymmetry and CPT invariance in the early universe
International Nuclear Information System (INIS)
Barshay, S.
1981-01-01
We discuss, and give a definite, simple phenomenological example, of the possibility that the baryon asymmetry is related to a failure of CPT invariance for a brief time interval at the origin of the universe. (orig.)
Masses and magnetic moments of triple heavy flavour baryons in ...
Indian Academy of Sciences (India)
The vital properties of these heaviest baryons in nature are their masses and ..... in bringing out a possible saturation property of the basic interactions within the ... forward to the experimental support to our predictions, from different future ...
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.)
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)
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 ...
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
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)
Heavy quark effective theory and heavy baryon transitions
International Nuclear Information System (INIS)
Hussain, F.
1992-01-01
The heavy quark effective theory (HQET) is applied to study the weak decay of heavy mesons and heavy baryons and to predict the form factors for heavy to heavy and heavy to light transitions. 28 refs, 10 figs, 2 tabs
Baryon production in e+e--annihilation at PETRA
International Nuclear Information System (INIS)
Bartel, W.; Cords, D.; Dittmann, P.; Eichler, R.; Felst, R.; Krehbiel, H.; Meier, K.; Naroska, B.; O'Neill, L.H.
1981-06-01
Data on anti p and anti Λ production by e + e - -annihilation at CM energies between 30 and 36 GeV are presented. Indication for an angular anticorrelation in events with baryon antibaryon pairs is seen. (orig.)
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
Self-Energy of Decuplet Baryons in Nuclear Matter
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...
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.)
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.)
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.)
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.)
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
Tracing the Baryon Cycle within Nearby Galaxies with a next-generation VLA
Kepley, Amanda A.; Leroy, Adam; Murphy, Eric J.; ngVLA Baryon Cycle Science Working Group
2017-01-01
The evolution of galaxies over cosmic time is shaped by the cycling of baryons through these systems, namely the inflow of atomic gas, the formation of molecular structures, the birth of stars, and the expulsion of gas due to associated feedback processes. The best way to study this cycle in detail are observations of nearby galaxies. These systems provide a complete picture of baryon cycling over a wide range of astrophysical conditions. In the next decade, higher resolution/sensitivity observations of such galaxies will fundamentally improve our knowledge of galaxy formation and evolution, allowing us to better interpret higher redshift observations of sources that were rapidly evolving at epochs soon after the Big Bang. In particular, the centimeter-to-millimeter part of the spectrum provides critical diagnostics for each of the key baryon cycling processes and access to almost all phases of gas in galaxies: cool and cold gas (via emission and absorption lines), ionized gas (via free-free continuum and recombination lines), cosmic rays and hot gas (via synchrotron emission and the Sunyaev-Zeldovich effect). This poster highlights a number of key science problems in this area whose solutions require a next-generation radio-mm interferometer such as the next-generation VLA.
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
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
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 effective quark potential in baryons
International Nuclear Information System (INIS)
Gromes, D.
1977-01-01
The splitting of the non-strange members of the first excited level [70,1 - ] 1 of baryon resonances is analysed. The spin-dependent forces (spin-spin, spin-orbit, tensor) are supposed to arise from the Coulomb term due to one-gluon exchange, from the long-range linearly rising part of the potential, and from additional 'hard-core' spin-spin terms which may be generated by higher-order graphs contributing to the qq kernel. For the long range part it is assumed either that it comes from a superposition of a vector and a scalar kernel of the form epsilon(γsup(μ) X γsub(μ) X 1) + (1 - epsilon)(1 X 1 X 1) (+ permutations), or, alternatively, that it arises from a vector exchange with an anomalous moment kappa in the quark-gluon vertex. Values of epsilon approximately 0 or kappa approximately -1 turn out to be favoured. The strong coupling constant and the slope of the linear potential come out in the correct order of magnitude. Very large hard-core spin-spin terms are needed. This fact makes the determination of the effective potential from the underlying theory of quantum chromodynamics as well as the phenomenological analysis of the observed spectra rather problematic. (Auth.)
First observation of a baryonic Bc+ decay.
Aaij, R; Adeva, B; Adinolfi, M; Affolder, A; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Anderson, J; Andreassen, R; Andreotti, M; Andrews, J E; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Bachmann, S; Back, J J; Badalov, A; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M-O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Borsato, M; Bowcock, T J V; Bowen, E; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; 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Donleavy, S; Dordei, F; Dorigo, M; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dreimanis, K; Dujany, G; Dupertuis, F; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Ely, S; Esen, S; Evans, H-M; Evans, T; Falabella, A; Färber, C; Farinelli, C; Farley, N; Farry, S; Fay, Rf; Ferguson, D; Fernandez Albor, V; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Fu, J; Furfaro, E; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; García Pardiñas, J; Garofoli, J; Garra Tico, J; Garrido, L; Gaspar, C; Gauld, R; Gavardi, L; Gavrilov, G; Geraci, A; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianelle, A; Giani', S; Gibson, V; Giubega, L; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Griffith, P; Grillo, L; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Hampson, T; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; He, J; Head, T; Heijne, V; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hoballah, M; Hombach, C; Hulsbergen, W; Hunt, P; Hussain, N; Hutchcroft, D; Hynds, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jaton, P; Jawahery, A; Jing, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kaballo, M; Kandybei, S; Kanso, W; Karacson, M; Karbach, T M; Karodia, S; Kelsey, M; Kenyon, I R; Ketel, T; Khanji, B; Khurewathanakul, C; Klaver, S; Klimaszewski, K; Kochebina, O; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kurek, K; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanfranchi, G; Langenbruch, C; Langhans, B; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Lefèvre, R; Leflat, A; Lefrançois, J; Leo, S; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Liles, M; Lindner, R; Linn, C; Lionetto, F; Liu, B; Lohn, S; Longstaff, I; Lopes, J H; Lopez-March, N; Lowdon, P; Lu, H; Lucchesi, D; Luo, H; Lupato, A; Luppi, E; Lupton, O; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Malde, S; Malinin, A; Manca, G; Mancinelli, G; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Märki, R; Marks, J; Martellotti, G; Martens, A; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; McSkelly, B; Meadows, B; Meier, F; Meissner, M; Merk, M; Milanes, D A; Minard, M-N; Moggi, N; Molina Rodriguez, J; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A-B; Mountain, R; Muheim, F; Müller, K; Mussini, M; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nicol, M; Niess, V; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Onderwater, G; Orlandea, M; Otalora Goicochea, J M; Owen, P; Oyanguren, A; Pal, B K; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrignani, C; Pazos Alvarez, A; Pearce, A; Pellegrino, A; Pepe Altarelli, M; Perazzini, S; Perez Trigo, E; Perret, P; Perrin-Terrin, M; Pescatore, L; Pesen, E; Petridis, K; Petrolini, A; Picatoste Olloqui, E; Pietrzyk, B; Pilař, T; Pinci, D; Pistone, A; Playfer, S; Plo Casasus, M; Polci, F; Poluektov, A; Polycarpo, E; Popov, A; Popov, D; Popovici, B; Potterat, C; Price, E; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Rachwal, B; Rademacker, J H; Rakotomiaramanana, B; Rama, M; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Reichert, S; Reid, M M; Dos Reis, A C; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Roa Romero, D A; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Perez, P; Roiser, S; Romanovsky, V; Romero Vidal, A; Rotondo, M; Rouvinet, J; Ruf, T; Ruiz, H; Ruiz Valls, P; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrie, M; Savrina, D; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Sepp, I; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Silva Coutinho, R; Simi, G; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, N A; Smith, E; Smith, E; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Steinkamp, O; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Stroili, R; Subbiah, V K; Sun, L; Sutcliffe, W; Swientek, K; Swientek, S; Syropoulos, V; Szczekowski, M; Szczypka, P; Szilard, D; Szumlak, T; T'Jampens, S; Teklishyn, M; Tellarini, G; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tresch, M; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vagnoni, V; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vázquez Sierra, C; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; de Vries, J A; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Websdale, D; Whitehead, M; Wicht, J; Wiedner, D; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, Z; Xu, Z; Yang, Z; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L; Zvyagin, A
2014-10-10
A baryonic decay of the B(c)(+) meson, B(c)(+) → J/ψppπ(+), is observed for the first time, with a significance of 7.3 standard deviations, in pp collision data collected with the LHCb detector and corresponding to an integrated luminosity of 3.0 fb(-1) taken at center-of-mass energies of 7 and 8 TeV. With the B(c)(+) → J/ψπ(+) decay as the normalization channel, the ratio of branching fractions is measured to be B(B(c)(+) → J/ψppπ(+))/B(B(c)(+) → J/ψπ(+)) = 0.143(-0.034)(+0.039)(stat) ± 0.013(syst). The mass of the B(c)(+) meson is determined as M(B(c)(+) = 6274.0 ± 1.8(stat) ± 0.4(syst) MeV/c(2), using the B(c)(+) → J/ψppπ(+) channel.
Soft RPV through the baryon portal
International Nuclear Information System (INIS)
Krnjaic, Gordan; Tsai, Yuhsin
2014-01-01
Supersymmetric (SUSY) models with R-parity generically predict sparticle decays with invisible neutralinos, which yield distinctive missing energy events at colliders. Since most LHC searches are designed with this expectation, the putative bounds on sparticle masses become considerably weaker if R-parity is violated so that squarks and gluinos decay to jets with large QCD backgrounds. Here we introduce a scenario in which baryonic R-parity violation (RPV) arises effectively from soft SUSY breaking interactions, but leptonic RPV remains accidentally forbidden to evade constraints from proton decay and FCNCs. The model features a global R-symmetry that initially forbids RPV interactions, a hidden R-breaking sector, and a heavy mediator that communicates this breaking to the visible sector. After R-symmetry breaking, the mediator is integrated out and an effective RPV A-term arises at tree level; RPV couplings between quarks and squarks arise only at loop level and receive additional suppression. Although this mediator must be heavy compared to soft masses, the model introduces no new hierarchy since viable RPV can arise when the mediator mass is near the SUSY breaking scale. In generic regions of parameter space, a light thermally-produced gravitino is stable and can be a viable dark matter candidate
Search for missing baryons through scintillation
International Nuclear Information System (INIS)
Habibi, F.
2011-06-01
Cool molecular hydrogen H 2 may be the ultimate possible constituent to the Milky-Way missing baryon. We describe a new way to search for such transparent matter in the Galactic disc and halo, through the diffractive and refractive effects on the light of background stars. By simulating the phase delay induced by a turbulent medium, we computed the corresponding illumination pattern on the earth for an extended source and a given passband. We show that in favorable cases, the light of a background star can be subjected to stochastic fluctuations of the order of a few percent at a characteristic time scale of a few minutes. We have searched for scintillation induced by molecular gas in visible dark nebulae as well as by hypothetical halo clumpuscules of cool molecular hydrogen (H 2 -He) during two nights, using the NTT telescope and the IR SOFI detector. Amongst a few thousands of monitored stars, we found one light-curve that is compatible with a strong scintillation effect through a turbulent structure in the B68 nebula. Because no candidate were found toward the SMC (Small Magellan Cloud), we are able to establish upper limits on the contribution of gas clumpuscules to the Galactic halo mass. We show that the short time-scale monitoring of a few 10 6 star*hour in the visible band with a >4 m telescope and a fast readout camera should allow one to interestingly quantify or constrain the contribution of turbulent molecular gas to the Galactic halo. (author)
Cold dense baryonic matter and compact stars
International Nuclear Information System (INIS)
Hyun Kyu Lee; Sang-Jin Sin; Mannque Rho
2011-01-01
Probing dense hadronic matter is thus far an uncharted field of physics. Here we give a brief summary of the highlights of what has been so far accomplished and what will be done in the years ahead by the World Class University III Project at Hanyang University in the endeavor to unravel and elucidate the multi-facet of the cold dense baryonic matter existing in the interior of the densest visible stable object in the universe, i.e. neutron stars, strangeness stars and/or quark stars, from a modest and simplified starting point of an effective field theory modeled on the premise of QCD as well as from a gravity dual approach of hQCD. The core of the matter of our research is the possible origin of the ∼ 99% of the proton mass that is to be accounted for and how the 'vacuum' can be tweaked so that the source of the mass generation can be uncovered by measurements made in terrestrial as well as space laboratories. Some of the issues treated in the program concern what can be done - both theoretically and experimentally - in anticipation of what's to come for basic physics research in Korea. (authors)
Heavy baryons as polarimeters at colliders
Energy Technology Data Exchange (ETDEWEB)
Galanti, Mario [Department of Physics and Astronomy, University of Rochester,Rochester, NY 14627-0171 (United States); Giammanco, Andrea [Centre for Cosmology, Particle Physics and Phenomenology, Université catholique de Louvain,B-1348 Louvain-la-Neuve (Belgium); National Institute of Chemical Physics and Biophysics,10143 Tallinn (Estonia); Grossman, Yuval [Laboratory for Elementary-Particle Physics, Cornell University,Ithaca, NY 14853 (United States); Kats, Yevgeny; Stamou, Emmanuel [Department of Particle Physics and Astrophysics, Weizmann Institute of Science,Rehovot 7610001 (Israel); Zupan, Jure [Department of Physics, University of Cincinnati,Cincinnati, OH 45221 (United States)
2015-11-10
In new-physics processes that produce b or c jets, a measurement of the initial b or c-quark polarization could provide crucial information about the structure of the new physics. In the heavy-quark limit, the b and c-quark polarizations are preserved in the lightest baryons they hadronize into, Λ{sub b} and Λ{sub c}, respectively. We revisit the prediction for the polarization retention after the hadronization process and extend it to the case of transverse polarization. We show how ATLAS and CMS can measure the b-quark polarization using semileptonic Λ{sub b} decays, and the c-quark polarization using Λ{sub c}{sup +}→pK{sup −}π{sup +} decays. For calibrating both measurements we suggest to use tt̄ samples in which these polarizations can be measured with precision of order 10% using 100 fb{sup −1} of data in Run 2 of the LHC. Measurements of the transverse polarization in QCD events at ATLAS, CMS and LHCb are motivated as well. The proposed measurements give access to nonperturbative QCD parameters relevant to the dynamics of the hadronization process.
Baryonic distributions in galaxy dark matter haloes - II. Final results
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.
Baryon Wilson loop area law in QCD
International Nuclear Information System (INIS)
Cornwall, J.M.
1996-01-01
There is still confusion about the correct form of the area law for the baryonic Wilson loop (BWL) of QCD. Strong-coupling (i.e., finite lattice spacing in lattice gauge theory) approximations suggest the form exp[-KA Y ], where K is the q bar q string tension and A Y is the global minimum area, generically a three-bladed area with the blades joined along a Steiner line (Y configuration). However, the correct answer is exp[-(K/2)(A 12 +A 13 +A 23 )], where, e.g., A 12 is the minimal area between quark lines 1 and 2 (Δ configuration). This second answer was given long ago, based on certain approximations, and is also strongly favored in lattice computations. In the present work, we derive the Δ law from the usual vortex-monopole picture of confinement, and show that, in any case, because of the 1/2 in the Δ law, this law leads to a larger value for the BWL (smaller exponent) than does the Y law. We show that the three-bladed, strong-coupling surfaces, which are infinitesimally thick in the limit of zero lattice spacing, survive as surfaces to be used in the non-Abelian Stokes close-quote theorem for the BWL, which we derive, and lead via this Stokes close-quote theorem to the correct Δ law. Finally, we extend these considerations, including perturbative contributions, to gauge groups SU(N), with N>3. copyright 1996 The American Physical Society
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
QCD equation of state of hot deconfined matter at finite baryon density. A quasiparticle perspective
International Nuclear Information System (INIS)
Bluhm, Marcus
2008-01-01
The quasiparticle model, based on quark and gluon degrees of freedom, has been developed for the description of the thermodynamics of a hot plasma of strongly interacting matter which is of enormous relevance in astrophysics, cosmology and for relativistic heavy-ion collisions as well. In the present work, this phenomenological model is extended into the realm of imaginary chemical potential and towards including, in general, different and independent quark flavour chemical potentials. In this way, nonzero net baryon-density effects in the equation of state are selfconsistently attainable. Furthermore, a chain of approximations based on formal mathematical manipulations is presented which outlines the connection of the quasiparticle model with the underlying gauge field theory of strong interactions, QCD, putting the model on firmer ground. The applicability of the model to extrapolate the equation of state known from lattice QCD at zero baryon density to nonzero baryon densities is shown. In addition, the ability of the model to extrapolate results to the chiral limit and to asymptotically large temperatures is illustrated by confrontation with available first-principle lattice QCD results. Basing on these successful comparisons supporting the idea that the hot deconfined phase can be described in a consistent picture by dressed quark and gluon degrees of freedom, a reliable QCD equation of state is constructed and baryon-density effects are examined, also along isentropic evolutionary paths. Scaling properties of the equation of state with fundamental QCD parameters such as the number of active quark flavour degrees of freedom, the entering quark mass parameters or the numerical value of the deconfinement transition temperature are discussed, and the robustness of the equation of state in the regions of small and large energy densities is shown. Uncertainties arising in the transition region are taken into account by constructing a family of equations of state
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
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.)
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
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
Search for the doubly charmed baryon at LHCb
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...
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.)
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.)
Measuring the total and baryonic mass profiles of the very massive CASSOWARY 31 strong lens
DEFF Research Database (Denmark)
Grillo, Claudio; Christensen, L.; Gallazzi, A.
2013-01-01
We investigate the total and baryonic mass distributions in deflector number 31 (CSWA 31) of the Cambridge And Sloan Survey Of Wide ARcs in the skY (CASSOWARY). We confirm spectroscopically a four-image lensing system at redshift 1.4870 with Very Large Telescope/X-shooter observations. The lensed...... find that the CSWA 31 deflector has properties suggesting it to be among the most distant and massive fossil systems studied so far. The unusually strong central dark matter dominance and the possible fossil nature of this system render it an interesting target for detailed tests of cosmological models...
Cosmological leverage from the matter power spectrum in the presence of baryon and nonlinear effects
International Nuclear Information System (INIS)
Bielefeld, Jannis; Huterer, Dragan; Linder, Eric V.
2015-01-01
We investigate how the use of higher wavenumbers (smaller scales) in the galaxy clustering power spectrum influences cosmological constraints. We take into account uncertainties from nonlinear density fluctuations, (scale dependent) galaxy bias, and baryonic effects. Allowing for substantially model independent uncertainties through separate fit parameters in each wavenumber bin that also allow for the redshift evolution, we quantify strong gains in dark energy and neutrino mass leverage with increasing maximum wavenumber, despite marginalizing over numerous (up to 125) extra fit parameters. The leverage is due to not only an increased number of modes but, more significantly, breaking of degeneracies beyond the linear regime
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
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.)
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)
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.
Accurate initial conditions in mixed Dark Matter--Baryon simulations
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 ...
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
Properties of Doubly Heavy Baryons in the Relativistic Quark Model
International Nuclear Information System (INIS)
Ebert, D.; Faustov, R.N.; Galkin, V.O.; Martynenko, A.P.
2005-01-01
Mass spectra and semileptonic decay rates of baryons consisting of two heavy (b or c) and one light quark are calculated in the framework of the relativistic quark model. The doubly heavy baryons are treated in the quark-diquark approximation. The ground and excited states of both the diquark and quark-diquark bound systems are considered. The quark-diquark potential is constructed. The light quark is treated completely relativistically, while the expansion in the inverse heavy-quark mass is used. The weak transition amplitudes of heavy diquarks bb and bc going, respectively, to bc and cc are explicitly expressed through the overlap integrals of the diquark wave functions in the whole accessible kinematic range. The relativistic baryon wave functions of the quark-diquark bound system are used for the calculation of the decay matrix elements, the Isgur-Wise function, and decay rates in the heavy-quark limit
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)
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.
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.)
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)
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
Chiral gravitational waves and baryon superfluid dark matter
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.
Diquark correlations in baryons on the lattice with overlap quarks
Energy Technology Data Exchange (ETDEWEB)
Babich, R.; Howard, J.; Rebbi, C. [Boston Univ., MA (United States). Dept. of Physics; Garron, N. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Hoelbling, C. [Wuppertal Univ. (Gesamthochschule) (Germany). Fachbereich Physik; Lellouch, L. [CNRS Luminy, Marseille (France). Centre de Physique Theorique]|[Wuppertal Univ. (Gesamthochschule) (Germany). Fachbereich Physik
2007-01-15
We evaluate baryon wave functions in both the Coulomb and Landau gauge in lattice QCD. These are constructed from quark propagators calculated with the overlap Dirac operator on quenched gauge configurations at {beta}=6. By comparing baryon states that differ in their diquark content, we find evidence for enhanced correlation in the scalar diquark channel, as favored by quark models. We also summarize earlier results for diquark masses in the Landau gauge, casting them in a form more easily compared with subsequent studies. (orig.)
Diquark correlations in baryons on the lattice with overlap quarks
International Nuclear Information System (INIS)
Babich, R.; Howard, J.; Rebbi, C.; Hoelbling, C.; Lellouch, L.; Wuppertal Univ.
2007-01-01
We evaluate baryon wave functions in both the Coulomb and Landau gauge in lattice QCD. These are constructed from quark propagators calculated with the overlap Dirac operator on quenched gauge configurations at β=6. By comparing baryon states that differ in their diquark content, we find evidence for enhanced correlation in the scalar diquark channel, as favored by quark models. We also summarize earlier results for diquark masses in the Landau gauge, casting them in a form more easily compared with subsequent studies. (orig.)
SU(6), baryonic decays of B-mesons and CP
International Nuclear Information System (INIS)
Wu, D.
1990-01-01
In this paper the four fermion weak decay Hamiltonian is expressed in terms of quark-antiquark creation operators with specific spin orientations. Then the SU(6) symmetry of the strong interactions among light quarks is imposed to find 8 invariant decay amplitudes for two body charmful baryonic decays of the B-mesons, 3 S-waves, 4 P- waves and 1 D-wave. Λ c branching ratio and some exclusive branching ratios are calculated based on the assumption of two body dominance in baryonic decay modes. Results on two body mesonic decays are also given. Relation between the SU(6) scheme and the quark diagram scheme is discussed
Study of flavor-tagged baryon production in B decay
Energy Technology Data Exchange (ETDEWEB)
Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Copty, N.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N. [University of Kansas, Lawrence, Kansas 66045 (United States); Kubota, Y.; Lattery, M.; Nelson, J.K.; Patton, S.; Poling, R.; Riehle, T.; Savinov, V.; Wang, R. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Alam, M.S.; Kim, I.J.; Ling, Z.; Mahmood, A.H.; ONeill, J.J.; Severini, H.; Sun, C.R.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Crawford, G.; Duboscq, J.E.; Fulton, R.; Fujino, D.; Gan, K.K.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Sung, M.; White, C.; Wanke, R.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio, 43210 (United States); Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Miao, T.; Miller, D.H.; Modesitt, M.; Shibata, E.I.; Shipsey, I.P.; Wang, P.N. [Purdue University, West Lafayette, Indiana 47907 (United States); Gibbons, L.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Coan, T.E.; Dominick, J.; Fadeyev, V.; Korolkov, I.; Lambrecht, M.; Sanghera, S.; Shelkov, V.; Stroynowski, R.; Volobouev, I.; Wei, G. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Gao, M.; Goldberg, M.; He, D.; Horwitz, N.; Kopp, S.; Moneti, G.C.; Mountain, R.; Muheim, F.; Mukhin, Y.; Playfer, S.; Skwarnicki, T.; Stone, S.; Xing, X. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.E.; Jain, V.; Marka, S. [Vanderbilt University, Nashville, Tennessee 37235 (United States); Gibaut, D.; Kinoshita, K.; Pomianowski, P.; Schrenk, S. [Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Barish, B.; Chadha, M.; Chan, S.; Cowen, D.
1997-01-01
Using data collected on the {Upsilon}(4S) resonance and the nearby continuum by the CLEO-II detector, we have studied combinations of baryons with leptons produced in the process {Upsilon}(4S){r_arrow}B{bar B}, B{r_arrow}lepton+X, {bar B}{r_arrow}baryon+X. Our results do not support models which Attribute the bulk of {Lambda}{sub c} production in {bar B} decay to the process b{r_arrow}cW{sup {minus}},W{sup {minus}}{r_arrow}{bar c}s. {copyright} {ital 1997} {ital The American Physical Society}
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
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)
Baryonic contributions to the dilepton spectra in relativistic heavy ion collisions
Energy Technology Data Exchange (ETDEWEB)
Bleicher, M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dutt-mazumder, A. K. [McGill Univ., Montreal, QC (Canada); Gale, C. [McGill Univ., Montreal, QC (Canada); Ko, C. M. [Texas A & M Univ., College Station, TX (United States); Koch, V. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2017-05-09
We investigate the baryonic contributions to the dilepton yield in high energy heavy ion collisions within the context of a transport model. The relative contribution of the baryonic and mesonic sources are examined. It is observed that most dominant among the baryonic channels is the decay of N*(1520) and mostly confined in the region below the rho peak. In a transport theory implementation we find the baryonic contribution to the lepton pair yield to be small.
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.)
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.)
International Nuclear Information System (INIS)
Nahrgang, Marlene; Schuster, Tim; Stock, Reinhard; Mitrovski, Michael; Bleicher, Marcus
2012-01-01
We explore the potential of net-baryon, net-proton and net-charge kurtosis measurements to investigate the properties of hot and dense matter created in relativistic heavy-ion collisions. Contrary to calculations in a grand-canonical ensemble we explicitly take into account exact electric and baryon charge conservation on an event-by-event basis. This drastically limits the width of baryon fluctuations. A simple model to account for this is to assume a grand-canonical distribution with a sharp cut-off at the tails. We present baseline predictions of the energy dependence of the net-baryon, net-proton and net-charge kurtosis for central (b≤2.75 fm) Pb+Pb/Au+Au collisions from E lab =2A GeV to √(s NN )=200 GeV from the UrQMD model. While the net-charge kurtosis is compatible with values around zero, the net-baryon number decreases to large negative values with decreasing beam energy. The net-proton kurtosis becomes only slightly negative for low √(s NN ). (orig.)
International Nuclear Information System (INIS)
Assinder, D.J.; Kelly, M.; Aston, S.R.
1984-01-01
Of the radionuclides entering the Esk Estuary from the Sellafield effluent discharges into the Irish Sea, the behaviour in the dissolved phase of 106 Ru, 134 Cs and 137 Cs is conservative whilst that of 238 Pu and sup(239,240)Pu is non-conservative. The latter leads to the enrichment of Pu in low salinity waters, probably by transfer from the particulate phase. This has repercussions on the distribution of Pu activity in the estuary, and also on the long term fate of sediment stored Pu. (author)
Directory of Open Access Journals (Sweden)
McCallion Andrew S
2009-01-01
Full Text Available Abstract Background Transcriptional regulatory elements are central to development and interspecific phenotypic variation. Current regulatory element prediction tools rely heavily upon conservation for prediction of putative elements. Recent in vitro observations from the ENCODE project combined with in vivo analyses at the zebrafish phox2b locus suggests that a significant fraction of regulatory elements may fall below commonly applied metrics of conservation. We propose to explore these observations in vivo at the human PHOX2B locus, and also evaluate the potential evidence for genome-wide applicability of these observations through a novel analysis of extant data. Results Transposon-based transgenic analysis utilizing a tiling path proximal to human PHOX2B in zebrafish recapitulates the observations at the zebrafish phox2b locus of both conserved and non-conserved regulatory elements. Analysis of human sequences conserved with previously identified zebrafish phox2b regulatory elements demonstrates that the orthologous sequences exhibit overlapping regulatory control. Additionally, analysis of non-conserved sequences scattered over 135 kb 5' to PHOX2B, provides evidence of non-conserved regulatory elements positively biased with close proximity to the gene. Furthermore, we provide a novel analysis of data from the ENCODE project, finding a non-uniform distribution of regulatory elements consistent with our in vivo observations at PHOX2B. These observations remain largely unchanged when one accounts for the sequence repeat content of the assayed intervals, when the intervals are sub-classified by biological role (developmental versus non-developmental, or by gene density (gene desert versus non-gene desert. Conclusion While regulatory elements frequently display evidence of evolutionary conservation, a fraction appears to be undetected by current metrics of conservation. In vivo observations at the PHOX2B locus, supported by our analyses of in
Low energy fermion number violation
International Nuclear Information System (INIS)
Peccei, R.D.
1989-01-01
After a brief aside on charge quantization in the standard electroweak theory, I concentrate on various aspects of anomaly induced fermion number violation in the standard model. A critical analysis of the role of sphalerons for the universe's baryon asymmetry is presented and the importance of calculating directly fermion number violating Green's functions is stressed. A physical interpretation of the recent observation of Ringwald, that coherent effects in the electroweak theory lead to catastrophic fermion number violation at 100 TeV, is discussed. Possible quantum effects which might spoil this semi-classical picture are examined
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'.
On the electromagnetic properties of the baryon octet
International Nuclear Information System (INIS)
Leinweber, D.B.; Woloshyn, R.M.; Draper, T.
1990-11-01
A numerical simulation of quenched QCD on a 24x12x12x24 lattice at β=5.9 is used to calculate the electric and magnetic form factors of the baryon octet. Magnetic moments, electric radii, magnetic radii, and magnetic transition moments are extracted from the form factors. (Author) (4 refs., 4 figs.)
Oscillations of the static meson fields at finite baryon density
International Nuclear Information System (INIS)
Florkowski, W.; Friman, B.; Technische Hochschule Darmstadt
1996-04-01
The spatial dependence of static meson correlation functions at finite baryon density is studied in the Nambu-Jona-Lasinio model. In contrast to the finite temperature case, we find that the correlation functions at finite density are not screened but exhibit long-range oscillations. The observed phenomenon is analogous to the Friedel oscillations in a degenerate electron gas. (orig.)