Decuplet baryons in hot medium
Azizi, K
2016-01-01
The thermal properties of the light decuplet baryons are investigated in the framework of the thermal QCD sum rules. In particular, the behavior of the mass and residue of the $\\Delta$, $\\Sigma^{*}$, $\\Xi^{*}$ and $\\Omega$ baryons with respect to temperature are analyzed taking into account the additional operators coming up in the Wilson expansion at finite temperature. It is found that the mass and residue of these particles remain overall unaffected up to $T\\simeq150~MeV$ but, after this point, they start to diminish, considerably.
Decuplet baryon masses in covariant baryon chiral perturbation theory
Ren, Xiu-Lei; Geng, Li-Sheng; Meng, Jie
2013-01-01
We present an analysis of the lowest-lying decuplet baryon masses in the covariant baryon chiral perturbation theory with the extended-on-mass-shell scheme up to next-to-next-to-next-to-leading order. In order to determine the $14$ low-energy constants, we perform a simultaneous fit of the $n_f=2+1$ lattice QCD data from the PACS-CS, QCDSF-UKQCD, and HSC Collaborations, taking finite-volume corrections into account self-consistently. We show that up to next-to-next-to-next-to-leading order on...
Li, Hao-Song; Chen, Xiao-Lin; Deng, Wei-Zhen; Zhu, Shi-Lin
2016-01-01
We have systematically investigated the magnetic moments and magnetic form factors of the decuplet baryons to the next-to-next-leading order in the framework of the heavy baryon chiral perturbation theory. Our calculation includes the contributions from both the intermediate decuplet and octet baryon states in the loops. We also calculate the charge and magnetic dipole form factors of the decuplet baryons. Our results may be useful to the chiral extrapolation of the lattice simulations of the decuplet electromagnetic properties.
Study of decuplet baryon resonances from lattice QCD
Alexandrou, C.; Negele, J. W.; Petschlies, M.; Pochinsky, A. V.; Syritsyn, S. N.
2016-06-01
A lattice QCD study of the strong decay width and coupling constant of decuplet baryons to an octet baryon-pion state is presented. The transfer matrix method is used to obtain the overlap of lattice states with decuplet baryon quantum numbers on the one hand and octet baryon-pion quantum numbers on the other as an approximation of the matrix element of the corresponding transition. By making use of leading-order effective field theory, the coupling constants as well as the widths for the various decay channels are determined. The transitions studied are Δ →π N , Σ*→Λ π , Σ*→Σ π and Ξ*→Ξ π . We obtain results for two ensembles of Nf=2 +1 dynamical fermion configurations: one using domain wall valence quarks on a staggered sea at a pion mass of 350 MeV and a box size of 3.4 fm and a second one using domain wall sea and valence quarks at pion mass 180 MeV and box size 4.5 fm.
Calculation of the decay width of decuplet baryons
Alexandrou, Constantia; Petschlies, Marcus; Pochinsky, Andrew V; Syritsyn, Sergey S
2015-01-01
We calculate the coupling constant and decay width of the decuplet to octet baryon transitions in lattice QCD using the transfer matrix method. The transition amplitude is related to the coupling constant and via the Fermi's Golden Rule to the decay width. The method is applicable for near-degeneracy of the energy levels of initial and final states and, when this condition is fulfilled, yields a good estimate of the decay width. We present results using a hybrid action with domain wall valence quarks on a staggered sea with $350$ MeV pion mass as well as for a domain wall fermion action with $180$ MeV pion mass. We find $\\Gamma\\left( \\Delta \\to \\pi\\,N \\right) = 119\\,( 8)\\,( 8)$ MeV for the transition of Delta to pion-nucleon within the unitary domain wall setup. We also report values for the decay widths of the $\\Sigma^*$ and $\\Xi*$ baryons.
Virtual decuplet effects on octet baryon masses in covariant baryon chiral perturbation theory
Ren, Xiu-Lei; Geng, Lisheng; Meng, Jie; Toki, Hiroshi
2013-01-01
We extend a previous analysis of the lowest-lying octet baryon masses in covariant baryon chiral perturbation theory (ChPT) by explicitly taking into account the contribution of the virtual decuplet baryons. Up to next-to-next-to-next-to-leading order (N$^3$LO), the effects of these heavier degrees of freedom are systematically studied. Their effects on the light-quark mass dependence of the octet baryon masses are shown to be relatively small and can be absorbed by the available low-energy c...
Charge radii of octet and decuplet baryons in chiral constituent quark model
Indian Academy of Sciences (India)
Neetika Sharma; Harleen Dahiya
2013-09-01
The charge radii of the spin-$\\dfrac{1}{2}^{+}$ octet and spin-$\\dfrac{3}{2}^{+}$ decuplet baryons have been calculated in the framework of chiral constituent quark model ( CQM) using a general parametrization method (GPM). Our results are not only comparable with the latest experimental studies but also agree with other phenomenological models. The effects of (3) symmetry breaking pertaining to the strangeness contribution and GPM parameters pertaining to the one-, two- and three-quark contributions have also been investigated in detail and are found to be the key parameters in understanding the non-zero values for the neutral octet $(n, \\sum^{0}, \\Xi, )$ and decuplet $(^{0}, \\sum^{*0}, \\Xi^{*0})$ baryons.
Octet-decuplet baryon mass splittings from self-consistent one-loop perturbation theory
International Nuclear Information System (INIS)
The bag model of confined relativistic quarks in chiral-invariant interaction with scalar, pseudoscalar, vector, and pseudovector mesons, as well as gluons, is used to calculate the masses and wave functions of the spin-1/2 baryon octet and spin-3/2 decuplet, using self-consistent Brillouin-Wigner bound state perturbation theory. Chiral symmetry breaking is invoked with the sigma model. SU (6) and SU (3) symmetries are broken by the experimental meson spectrum, and a strange quark mass. Mass corrections are calculated to one loop order, limited to the baryons of the octet and decuplet and the lowest lying mesons. Encouraging results are obtained, especially for the Δ - N and the Σ - Λ splittings. Convergence and stability have not been demonstrated, but are evidently improved by the self-consistency requirement. An initial parameter tuning gives a fit to all the octet and decuplet masses within ≤0.02 GeV, at the price of choosing the bag radius, the non-strange baryon input bag mass, and the strange quark mass. Even these small discrepancies can be dramatically reduced by fine-tuning the vector meson coupling and including an instanton contribution peculiar to the Λ. (orig.)
The calculation of the quark distribution amplitudes of decuplet baryons by means of QCD sum rules
International Nuclear Information System (INIS)
Using the QCD sum rule technique, we derive the quark distribution amplitudes of the decuplet memebers Δ(1232), Σ*(1385), Ξ*(1530) and Ω(1672). Generalizing the treatment of the Bethe-Salpeter amplitude, we can distinguish spin- and orbital- angular momentum parts of the quark distributions and establish separate sum rules for the contributions. Projecting out the angular momentum 1/2 contributions, we obtain sum rules which are saturated by the lowest resonance in the given iso spin channel, thus resolving deficiencies of the standard approach. We find that for helicity 1/2 the spin part of the quark distributions is asymmetric. Also the orbital angular momentum contributions are extremely asymmetric and tend to decrease the asymmetry of the spin part. As a result of SU(3) symmetry breaking, configuration mixing occurs and the decuplet baryons Σ* and Ξ* receive octet contributions. The antisymmetric part of these octet contributions is calculated. (orig.)
Magnetic moments of JP = 3/2+ decuplet baryons using statistical model
Kaur, Amanpreet
2015-01-01
A suitable wave function for baryon decuplet is framed with inclusion of sea containing quark- gluon Fock states. Relevant operator formalism is applied to calculate magnetic moments of JP = 3 2 + baryon decuplet. Statistical model assumes decomposition of baryonic state in various quark-gluon Fock states such as jqqqijgi; jqqqijggi; jqqqijgggi with possibility gluon emitting qq pairs condensates due to the subprocesses like g , qq; g , gg and g , qg where qq = uu; dd; ss. Statistical approach and detailed balance principle in combination is used to find the relative probabilities of these Fock states in avor, spin and color space. The total number of partons (sea) in this formalism are restricted to three gluons due to limited free energy of gluon and suppressed number of strange quark-antiquark pairs. The combined approach is used to calculate the magnetic moments, importance of strangeness in the sea (scalar, vector and tensor). Our approach has confirmed the scalar-tensor sea dominancy over vector sea. Va...
Nonrelativistic chiral expansion and nonleptonic decays of octet and decuplet baryons
International Nuclear Information System (INIS)
We discuss the chiral lagrangian for JP=1/2+ octet and JP=3/2+ decuplet baryons in the language of the heavy particle effective theory. We show that the effective theory qualitatively reproduces the Pauli amplitudes for the nonleptonic hyperon decays, calculated recently by Trofimenkoff. We discuss the relation of our results to nonrelativistic SU(6). We argue that we can consistently classify the meson-baryon interaction terms in lowest order in the momentum expansion according to their transformation properties under nonrelativistic SU(6). Nevertheless, the theory as a whole remains explicitly Lorentz invariant. We explain why this does not run afoul of the theorems concerning interacting relativistic SU(6) theories. We use this SU(6) classification to discuss the relation between the nonleptonic Ω- decays and the nonleptonic decays of the octet baryons. We find that the Ω- decays cannot be explained by any interaction term transforming simply under SU(6) because the nonleptonic Ω- decays do not display the pronounced ΔI=1/2 enhancement seen in the octet hyperon decays. Any explanation of the Ω- decays requires a fine tuning of the parameters in the effective theory. We speculate that this problem may point to a flaw in the basic assumption that ΔI=1/2 four-quark operators, universally enhanced by QCD, are the dominant mechanism behind the ΔS=1 nonleptonic decays. (orig.)
Akiyama, S; Akiyama, Satoru; Futami, Yasuhiko
2006-01-01
Mesonic fluctuations around the chiral solitons are investigated in the SU(3) chiral quark soliton model. Since the soliton takes the non-hedgehog shape for the hyperons and the hedgehog one for the non-hedgehog baryons in our approach, the fluctuations also change according to the baryonic state. The quantum corrections to the masses (the Casimir energies) are estimated for the octet and decuplet baryons. The lack of the confinement in this model demands the cutoff on the energy of the fluctuations. Under the assumption that the value of the cutoff energy is $2\\times$(the lightest constituent quark mass), these calculation reproduces the masses of the baryons within 15 % error.
International Nuclear Information System (INIS)
Samples of approx.= 1900 identified protons and approx.= 500 Λ have been used to search for decuplet baryon production in e+e- annihilation at a c.m. energy of 34.4 GeV. The pπ+ and Λπsup(+-) invariant mass spectra contain no Δ or Σsup(*) signals. Upper limits, at 95% confidence level, are that less than 12% of all p and less than 26% of all Λ come from the decay of doubly charged Δ and singly charged Σsup(*) states respectively. These limits correspond to production rates of ++ and ++ and Σsup(*+-) is suppressed by a factor > or approx. 9 relative to octet baryons of the same strangeness. (orig.)
International Nuclear Information System (INIS)
Samples of proportional1,900 identified protons and proportional500 Λ have been used to search for decuplet baryon production in e+e- annihilation at a c.m. energy of 34.4 GeV. The pπ4 and Λπsup(+-) invariant mass spectra contain no Δ or Σsup(*) signals. Upper limits, at 95% confidence level, are that less than 12% of all p and less than 26% of all Λ come from the decay of doubly charged Δ and singly charged Σsup(*) states respectively. These limits correspond to production rates of ++ and ++ and Σsup(*+-) is suppressed by a factor > or approx.9 relative to octet baryons of the same strangeness. (orig.)
Charge specific baryon mass formulas with deformed SU_q(3) flavor symmetry
Gresnigt, Niels G
2016-01-01
The quantum group $SU_q(3)=U_q(su(3))$ is taken as a baryon flavor symmetry to derive mass sum rules for octet and decuplet baryons. Accounting for electromagnetic contributions to baryons masses to zeroth order, the new charge specific $q$-deformed octet and decuplet baryon mass formulas are accurate to 0.02% and 0.08% respectively. A new relation between the octet and decuplet baryon masses that is accurate to 1.0% is derived. An explicit formula for the Cabibbo angle, taken to be $\\frac{\\pi}{14}$, in terms of the deformation parameter $q$ and $J^P$ of the baryons is obtained.
Large-Nc operator analysis of 2-body meson-baryon counter terms in the chiral Lagrangian
International Nuclear Information System (INIS)
The chiral SU(3) Lagrangian with the baryon octet and decuplet fields is considered. The Q2 counter terms involving the decuplet fields are constructed. We derive the parameter correlation implied by the 1/Nc expansion at leading order in QCD.
Baryon magnetic moments in the effective quark Lagrangian approach
Simonov, YA; Tjon, JA; Weda, J; Simonov, Yu A.
2002-01-01
An effective quark Lagrangian is derived from first principles through bilocal gluon field correlators. It is used to write down equations for baryons, containing both perturbative and nonperturbative fields. As a result one obtains magnetic moments of octet and decuplet baryons without the introduc
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.)
On the quark-mass dependence of baryon ground-state masses
International Nuclear Information System (INIS)
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.)
Renormalization of the baryon axial vector current in large-Nc chiral perturbation theory
International Nuclear Information System (INIS)
The baryon axial vector current is considered within the combined framework of large-Nc baryon chiral perturbation theory (where Nc is the number of colors) and the baryon axial vector couplings are extracted. Loop graphs with octet and decuplet intermediate states are systematically incorporated into the analysis
Anisotropic Lattice QCD Studies of Penta-quark Anti-decuplet
Ishii, N; Iida, H; Oka, M; Okiharu, F; Suganuma, H
2004-01-01
Anti-decuplet penta-quark baryon is studied with the quenched anisotropic lattice QCD for accurate measurement of the correlator. Both the positive and negative parity states are studied using a non-NK type interpolating field with I=0 and J=1/2. After the chiral extrapolation, the lowest positive parity state is found at m_{Theta} \\simeq 2.25 GeV, which is too massive to be identified with the experimentally observed Theta^+(1540). The lowest negative parity state is found at m_{Theta}\\simeq 1.75 GeV, which is rather close to the empirical value. To confirm that this state is a compact 5Q resonance, a new method with ``hybrid boundary condition (HBC)'' is proposed. The HBC analysis shows that the observed state in the negative parity channel is an NK scattering state.
Finite-volume effects on octet-baryon masses in covariant baryon chiral perturbation theory
Geng, Li-Sheng; Ren, Xiu-Lei; Martin-Camalich, J.; Weise, W.
2011-01-01
We study finite-volume effects on the masses of the ground-state octet baryons using covariant baryon chiral perturbation theory (ChPT) up to next-to-leading order by analyzing the latest $n_f=2+1$ lattice Quantum ChromoDynamics (LQCD) results from the NPLQCD collaboration. Contributions of virtual decuplet baryons are taken into account using the "consistent" coupling scheme. We compare our results with those obtained from heavy baryon ChPT and show that, although both approaches can describ...
Density-dependent effective baryon-baryon interaction from chiral three-baryon forces
Petschauer, Stefan; Kaiser, Norbert; Meißner, Ulf-G; Weise, Wolfram
2016-01-01
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 Lambda-nucleon 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 ...
Lowest-lying octet baryon masses in covariant baryon chiral perturbation theory
Ren, Xiu-Lei; Geng, Lisheng; Meng, Jie; Toki, Hiroshi
2013-01-01
We report on a systematic study of the ground-state octet baryon masses in the covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme up to next-to-next-to-next-to-leading order, taking into account the contributions of the virtual decuplet baryons. A reasonable description of the lattice results is achieved by fitting simultaneously all the publicly available $n_f = 2+1$ lattice QCD data. It confirms that the various lattice simulations are consist...
One-loop corrections to the baryon axial vector current
Indian Academy of Sciences (India)
M A Hernández-Ruíz
2012-10-01
The symmetry breaking corrections to the pion–baryon couplings vanish to first order in $1/N_{c}$, where $N_{c}$ is the number of colours. Loop graphs with octet and decuplet intermediate states cancel to various orders in $N_{c}$ as a consequence of the large-$N_{c}$ spin-flavour symmetry of QCD baryons. The baryon axial vector current is computed at one-loop order in heavy baryon chiral perturbation theory in the large Nc limit. $1/N_{c}$ corrections in the case of $g_{A}$ in QCD are presented here.
Strangeness in the baryon ground states
Semke, A
2012-01-01
We compute the strangeness content of the baryon ground states based on an analysis of recent lattice simulations of the BMW, PACS, LHPC and HSC groups for the pion-mass dependence of the baryon masses. Our results rely on the relativistic chiral Lagrangian and large-$N_c$ sum rule estimates of the counter terms relevant for the baryon masses at N$^3$LO. A partial summation is implied by the use of physical baryon and meson masses in the one-loop contributions to the baryon self energies. A simultaneous description of the lattice results of the BMW, LHPC, PACS and HSC groups is achieved. We predict the pion- and strangeness sigma terms and the pion-mass dependence of the octet and decuplet ground states at different strange quark masses.
Observation of octet and decuplet hyperons in e+e- annihilation at 10 GeV centre-of-mass energy
International Nuclear Information System (INIS)
Results on hyperon production are reported for data accumulated at 10 GeV centre-of-mass energy with the ARGUS detector. Signals for both the octet states Λ, Σ0 and Ξ- and the decuplet states Σ±(1385), Ξ0(1530) and Ω- are observed (references to a specific state are to be interpreted as also implying the charge conjugate state), some for the first time in e+e- annihilation. Baryon rates from Υdir (1S) decays are enhanced by a factor of about 3 over the continuum. (orig.)
Calculation of baryon masses in quantum chromodynamics
International Nuclear Information System (INIS)
The polarization operator of quark currents with the baryon quantum numbers is considered in quantum chromodynamics. The non-zero mean vacuum of the field operator products are taken into account. The sum rules are obtained assuming that in the virtuality region approximately 1 GeV, among the mean vacuum values violating the chiral invariance, the most important is . Saturating these sum rules by the lowest baryonic states one is able to calculate the masses of the isobar Δ and nucleon N, Msub(Δ) 1.4 GeV, Msub(N) = 1 GeV, up to 15 % through the known value . The mass splitting in the baryonic decuplet Msub(Σ*) - Msub(Δ) = 125 MeV is calculated in the first order in the current strange quark mass msub(s) = 150 MeV. Certain results for that baryonic resonances have been obtained
Staggered Heavy Baryon Chiral Perturbation Theory
Bailey, Jon A
2007-01-01
Although taste violations significantly affect the results of staggered calculations of pseudoscalar and heavy-light mesonic quantities, those entering staggered calculations of baryonic quantities have not been quantified. Here I develop staggered chiral perturbation theory in the light-quark baryon sector by mapping the Symanzik action into heavy baryon chiral perturbation theory. For 2+1 dynamical quark flavors, the masses of flavor-symmetric nucleons are calculated to third order in partially quenched and fully dynamical staggered chiral perturbation theory. To this order the expansion includes the leading chiral logarithms, which come from loops with virtual decuplet-like states, as well as terms the order of the cubed pion mass, which come from loops with virtual octet-like states. Taste violations enter through the meson propagators in loops and tree-level terms the order of the squared lattice spacing. The pattern of taste symmetry breaking and the resulting degeneracies and mixings are discussed in d...
Rotational Spectra of the Baryons and Mesons
Akers, D
2003-01-01
An investigation of the rotational spectra of baryons and mesons is conducted. Diakonov, Petrov and Polyakov claimed that all light baryons are rotational excitations. A study of the history of particle physics indicates that the ideas of rotational spectra can be originally attributed to a constituent-quark (CQ) model as proposed by Mac Gregor. Later research advanced spin-orbit splitting in a deformed model as suggested by Bhaduri and others. In the present work, we show from current data that the rotational spectra of baryons and mesons are in agreement with the original claims of Mac Gregor: namely, the values for the rotational energies Erot of particles merge with those of nuclear rotational bands in light nuclei. It is also shown that particles of different isotopic spins are separated in mass by a 70 MeV quantum, which is related to the SU(3) decuplet mass spacing as originally proposed by Gell-Mann.
Chiral extrapolations and strangeness in the baryon ground states
Lutz, Matthias F M
2013-01-01
We review the quark-mass dependence of the baryon octet and decuplet masses as obtained from recent lattice simulations of the BMW, PACS-CS, LHPC, HSC and QCDSF-UKQCD groups. Our discussion relies on the relativistic chiral Lagrangian and large-$N_c$ sum rule estimates of the counter terms relevant for the baryon masses at N$^3$LO. A partial summation is implied by the use of physical baryon and meson masses in the one-loop contributions to the baryon self energies. In our analysis the physical masses are reproduced exactly by means of a suitable set of linear constraints. A quantitative and simultaneous description of all lattice results is achieved in terms of a six parameter fit, where the symmetry conserving counter term that are relevant at N$^3$LO are not yet being used. For pion masses larger than 300 MeV there appears to be an approximate linear pion-mass dependence of all octet and decuplet baryon masses. We discuss the pion- and strangeness sigma terms of the baryon octet states.
On the quark-mass dependence of the baryon ground-state masses
Semke, A
2011-01-01
We perform a chiral extrapolation of the baryon octet and decuplet masses in a relativistic formulation of chiral perturbation theory. A partial summation is assumed as implied by the use of physical baryon and meson masses in the one-loop diagrams. Upon a chiral expansion our results are consistent with strict chiral perturbation theory at the next-to-next-to-next-to-leading order. All counter terms are correlated by a large-$N_c$ operator analysis. Our results are confronted with recent results of unquenched three flavor lattice simulations. We adjust the parameter set to the pion-mass dependence of the nucleon and omega masses as computed by the BMW group and predict the pion-mass dependence of the remaining baryon octet and decuplet states. The current lattice simulations can be described accurately and smoothly up to pion masses of about 600 MeV. In particular we recover the recent results of HSC without any further adjustments.
Chiral perturbation theory analysis of baryon temperature mass shifts
Bedaque, P F
1995-01-01
We compute the finite temperature pole mass shifts of the octet and decuplet baryons using heavy baryon chiral perturbation theory and the 1/N_c expansion, where N_c is the number of QCD colors. We consider the temperatures of the order of the pion mass m_\\pi, and expand truncate the chiral and 1/N_c expansions assuming that m_\\pi \\sim 1/N_c. There are three scales in the problem: the temperature T, the pion mass m_\\pi, and the octet--decuplet mass difference. Therefore, the result is not simply a power series in T. We find that the nucleon and \\Delta temperature mass shifts are opposite in sign, and that their mass difference changes by 20% in the temperature range 90 MeV < T < 130 MeV, that is the range where the freeze out in relativistic heavy ion collisions is expected to occur. We argue that our results are insensitive to the neglect of 1/N_c- supressed effects; the main purpose of the 1/N_c expansion in this work is to justify our treatment of the decuplet states.
Faria da Veiga, Paulo A.; O'Carroll, Michael; Valencia Alvites, José C.
2016-03-01
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.
Polarized pK{sup -} scattering in Unitary Baryon Chiral Perturbation Theory
Energy Technology Data Exchange (ETDEWEB)
Bouzas, Antonio O. [CINVESTAV-IPN, Departamento de Fisica Aplicada, Carretera Antigua a Progreso Km. 6, Apdo. Postal 73 ' ' Cordemex' ' , Merida, Yucatan (Mexico)
2010-03-15
We study pK{sup -} scattering in the energy range from threshold through the {lambda} (1520) peak in UBChPT, taking into account O(q) vertices from meson-baryon contact interactions and s- and u-channel ground-state baryon exchange, s- and u-channel decuplet- and nonet-baryon exchange and t -channel vector-meson exchange, as well as O(q {sup 2}) flavor-breaking vertices. Detailed fits to data are presented, including a substantial body of differential cross-section data with meson momentum q{sub lab} >300 MeV not considered in previous treatments. (orig.)
Partially quenched study of strange baryon with N{sub f}=2 twisted mass fermions
Energy Technology Data Exchange (ETDEWEB)
Drach, Vincent; Brinet, Mariane; Carbonell, Jaume [UJF, CNRS/IN2P3, INPG, Grenoble (FR). Lab. de Physique Subatomique et de Cosmologie] (and others)
2009-06-15
We present results on the mass of the baryon octet and decuplet using two flavors of light dynamical twisted mass fermions. The strange quark mass is fixed to its physical value from the kaon sector in a partially quenched set up. Calculations are performed for light quark masses corresponding to a pion mass in the range 270-500 MeV and lattice sizes of 2.1 fm and 2.7 fm. We check for cut-off effects and isospin breaking by evaluating the baryon masses at two different lattice spacings. We carry out a chiral extrapolation for the octet baryons and discuss results for the {omega}. (orig.)
Partially quenched study of strange baryon with Nf = 2 twisted mass fermions
Drach, V; Carbonell, J; Alexandrou, Z L C; Korzec, T; Koutsou, G; Baron, R; Guichon, P; Pène, O; Pallante, E; Reker, S; Urbach, C; Jansen, K
2008-01-01
We present results on the mass of the baryon octet and decuplet using two flavors of light dynamical twisted mass fermions. The strange quark mass is fixed to its physical value from the kaon sector in a partially quenched set up. Calculations are performed for light quark masses corresponding to a pion mass in the range 270-500 MeV and lattice sizes of 2.1 fm and 2.7 fm. We check for cut-off effects and isospin breaking by evaluating the baryon masses at two different lattice spacings. We carry out a chiral extrapolation for the octet baryons and discuss results for the Omega.
Zero temperature properties of mesons and baryons from an extended linear sigma-model
International Nuclear Information System (INIS)
An extended linear sigma model with mesons (q q-bar states) and baryons (qqq states) is presented. The model contains a low energy multiplet for every hadronic particle type, namely a scalar, a pseudoscalar, a vector and an axialvector nonet, a baryon octet and a baryon decuplet. The model parameters are determined through a multiparametric minimalization with the help of well known physical quantities. It is found that the considered zero temperature quantities (masses and decay widths) can be described well at tree-level and are in good agreement with the experimental data.
Rate equation network for baryon production in high energy nuclear collisions
International Nuclear Information System (INIS)
We develop and solve a network of rate equations for the production of baryons and antibaryons in high energy nuclear collisions. We include all members of the baryon octet and decuplet and allow for transformations among them. This network is solved during a relativistic 2+1 hydrodynamical expansion of the of the hot matter created in the collision. As an application we compare to the number of protons, Λ's, negative cascades, and Ω baryons measured at midrapidity in central collisions of gold nuclei at 65 GeV per nucleon at the Relativistic Heavy Ion Collider (RHIC)
Baryon spectroscopy at ELPH and LEPS2
Ishikawa, Takatsugu
2014-09-01
Baryon spectroscopy is an important testing ground for understanding low energy QCD. Meson photoproduction is complementary to π induced reactions for studying excited baryons. Among the meson photo-produced reactions, the neutron target, kaon photo-produced, and multi-meson photo-produced reactions are important to reveal the properties of baryon resonances. The photoproduction experiments at ELPH and the planned experiments at LEPS2 will be discussed. The nucleon and Δ resonances are studied with an electromagnetic calorimeter FOREST at ELPH, Tohoku University by using various photoproduction reactions. A narrow resonance observed at W-75 MeV in η photoproduction on the neutron is of great interest. It would be attributed to a member of anti-decuplet pentaquark baryons with hidden strangeness since no signature corresponding to this bump has been observed so far in the proton channel. Multi-meson/kaon photoproduction is a good tool to study highly excited baryons. The results obtained at ELPH and planned experiments at LEPS2 will be presented.
International Nuclear Information System (INIS)
This paper contains a discussion of the spectrum of the lowest-lying charm baryons and review the experimental status of the masses of charm baryons and briefly comment on theoretical attempts to understand their spectroscopy. Lifetime measurements and lifetime hierarchies suggested by the interplay of various theoretical mechanisms contributing to the decay and semileptonic decays of charm baryons are discussed. It also treats exclusive nonleptonic charm baryon decays, where there are more data to be compared to theoretical modeling, and contains a summary and an outlook on future charm baryon experiments
Bottom Baryon Decays to Pseudoscalar Meson and Pentaquark
Cheng, Hai-Yang
2015-01-01
Based on SU(3) flavor symmetry, we decompose the decay amplitudes of bottom baryon decays to a pseudoscalar meson and an octet or a decuplet pentaquark in terms of three invariant amplitudes $T_1$ and $T_{2,3}$ corresponding to external $W$-emission and internal $W$-emission diagrams, respectively. For antitriplet bottom baryons $\\Lambda_b^0,\\Xi_b^0$ and $\\Xi_b^-$, their decays to a decuplet pentaquark proceed only through the internal $W$-emission diagram. Assuming the dominance from the external $W$-emission amplitudes, we present an estimate of the decay rates relative to $\\Lambda_b^0\\to P_p^+K^-$, where $P_p^+$ is the hidden-charm pentaquark with the same light quark content as the proton. Hence, our numerical results will provide a very useful guideline to the experimental search for pentaquarks in bottom baryon decays. For example, $\\Xi_b^0\\to P_{\\Sigma^+}K^-$, $\\Xi_b^-\\to P_{\\Sigma^-}\\bar K^0$, $\\Omega_b^-\\to P_{\\Xi^-}\\bar K^0$ and $\\Omega_b^-\\to P_{\\Xi^0}K^-$ may have rates comparable to that of $\\Lam...
Quark Spin and Orbital Angular Momentum in the Baryon
Song, X.
1999-01-01
The spin and orbital angular momentum carried by different quark flavors in the nucleon are calculated in the SU(3) chiral quark model with symmetry-breaking. The model is extended to all octet and decuplet baryons. In this model, the reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital motion of quarks and antiquarks. The orbital angular momentum for each quark flavor in the proton as function of the partition factor $\\kappa...
Penta-Quark Anti-Decuplet in Anisotropic Lattice QCD
Ishii, N; Iida, H; Oka, M; Okiharu, F; Suganuma, H
2005-01-01
The penta-quark(5Q) Theta^+(1540) is studied in anisotropic lattice QCD with renormalized anisotropy a_s/a_t=4 for a high-precision measurement. Both the positive and the negative parity 5Q baryons are studied using a non-NK type interpolating field with I=0 and J=1/2. After the chiral extrapolation, the lowest positive parity state is found at m_{Theta}\\simeq 2.25 GeV, which is too heavy to be identified with Theta^+(1540). In the negative parity channel, the lowest energy state is found at m_{Theta}\\simeq 1.75 GeV. Although it is rather close to the empirical value, it is considered to be an NK scattering state rather than a localized resonance state.
International Nuclear Information System (INIS)
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/mQ 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.)
D-wave baryon resonances with charm from coupled-channel dynamics
Hofmann, J
2006-01-01
Identifying the zero-range exchange of vector mesons as the driving force for the s-wave scattering of pseudo-scalar mesons off the baryon ground states, the spectrum of ${3/2}^-$ molecules is computed. We predict a strongly bound 15-plet of $C=-1$ states. A narrow crypto-exotic octet of charm-zero states is foreseen. In the $C=+1$ sector a sextet of narrow resonances is formed due to the interaction of D mesons with the baryon decuplet. A strongly bound triplet of double-charm states is a consequence of coupled-channel dynamics driven by the D mesons.
On light baryons and their excitations
Eichmann, Gernot; Sanchis-Alepuz, Helios
2016-01-01
We study ground states and excitations of light octet and decuplet baryons within the framework of Dyson-Schwinger and Faddeev equations. We improve upon similar approaches by explicitly taking into account the momentum-dependent dynamics of the quark-gluon interaction that leads to dynamical chiral symmetry breaking. We perform calculations in both the three-body Faddeev framework and the quark-diquark approximation in order to assess the impact of the latter on the spectrum. Our results indicate that both approaches agree well with each other. The resulting spectra furthermore agree one-to-one with experiment, provided well-known deficiencies of the rainbow-ladder approximation are compensated for. We also discuss the mass evolution of the Roper and the excited Delta with varying pion mass and analyse the internal structure in terms of their partial wave decompositions.
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.
Staggered heavy baryon chiral perturbation theory
Bailey, Jon A.
2008-03-01
Although taste violations significantly affect the results of staggered calculations of pseudoscalar and heavy-light mesonic quantities, those entering staggered calculations of baryonic quantities have not been quantified. Here I develop staggered chiral perturbation theory in the light-quark baryon sector by mapping the Symanzik action into heavy baryon chiral perturbation theory. For 2+1 dynamical quark flavors, the masses of flavor-symmetric nucleons are calculated to third order in partially quenched and fully dynamical staggered chiral perturbation theory. To this order the expansion includes the leading chiral logarithms, which come from loops with virtual decuplet-like states, as well as terms of O(mπ3), which come from loops with virtual octet-like states. Taste violations enter through the meson propagators in loops and tree-level terms of O(a2). The pattern of taste symmetry breaking and the resulting degeneracies and mixings are discussed in detail. The resulting chiral forms are appropriate to lattice results obtained with operators already in use and could be used to study the restoration of taste symmetry in the continuum limit. I assume that the fourth root of the fermion determinant can be incorporated in staggered chiral perturbation theory using the replica method.
Magnetic moments of cascade baryons with strange sea in statistical model
International Nuclear Information System (INIS)
Study of hadrons can help to enrich our knowledge of its structure. Various recent experimental facilities at BASE, COMPASS etc. have provided opportunities for measurements of hadronic properties with an additional strangeness degree of freedom and search for exotic particles. Experimentally, at present magnetic moments of Δ++, Δ0 and Ω- are known. Magnetic moments of decuplet particles have not been measured experimentally because the particles decay strongly and thus do not live long enough. The present work analyses the contribution of sea-quarks to magnetic moment of cascade baryons of JP=3/2+ decuplet. For this, the methodology is based on the statistical model presented. The results are compared with the predictions of other models
Flavor dependence of baryon melting temperature in effective models of QCD
Torres-Rincon, Juan M; Aichelin, Joerg
2015-01-01
We apply the three-flavor (Polyakov-)Nambu-Jona-Lasinio model to generate baryons as quark-diquark bound states using many-body techniques at finite temperature. All the baryonic states belonging to the octet and decuplet flavor representations are generated in the isospin-symmetric case. For each state we extract the melting temperature at which the baryon may decay into a quark-diquark pair. We seek for an evidence of the strangeness dependence of the baryon melting temperature as suggested by the statistical thermal models and supported by lattice-QCD results. A clear and robust signal for this claim is found, pointing to a flavor dependence of the hadronic deconfinement temperature.
Kaplunovsky, Vadim; Melnikov, Dmitry; Sonnenschein, Jacob
2012-01-01
In the large N limit cold dense nuclear matter must be in a lattice phase. This applies also to holographic models of hadron physics. In a class of such models, like the generalized Sakai-Sugimoto model, baryons take the form of instantons of the effective flavor gauge theory that resides on probe flavor branes. In this paper we study the phase structure of baryonic crystals by analyzing discrete periodic configurations of such instantons. We find that instanton configurations exhibit a serie...
Low-lying baryon spectrum with two dynamical twisted mass fermions
Energy Technology Data Exchange (ETDEWEB)
Alexandrou, C. [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Computation-based Science and Technology Research Center, Cyprus Institute, Nicosia (Cyprus); Baron, R.; Guichon, P. [CEA-Saclay, IRFU/Service de Physique Nucleaire, Gif-sur-Yvette (France); Carbonell, J.; Drach, V. [UJF/CNRS/IN2P3, Grenoble (France). Lab. de Physique Subatomique et Cosmologie; Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Korzec, T. [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Pene, O. [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique
2009-10-15
The masses of the low lying baryons are evaluated using two degenerate flavors of twisted mass sea quarks corresponding to pseudo scalar masses in the range of about 270 MeV to 500 MeV. The strange valence quark mass is tuned to reproduce the mass of the kaon in the physical limit. The tree-level Symanzik improved gauge action is employed. We use lattices of spatial size 2.1 fm and 2.7 fm at two values of the lattice spacing with r{sub 0}/a=5.22(2) and r{sub 0}/a=6.61(3). We check for both finite volume and cut-off effects on the baryon masses. We performed a detailed study of the chiral extrapolation of the octet and decuplet masses using SU(2) {chi}PT. The lattice spacings determined using the nucleon mass at the physical point are consistent with the values extracted using the pion decay constant. We examine the issue of isospin symmetry breaking for the octet and decuplet baryons and its dependence on the lattice spacing. We show that in the continuum limit isospin breaking is consistent with zero, as expected. The baryon masses that we find after taking the continuum limit and extrapolating to the physical limit are in good agreement with experiment. (orig.)
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.
Low-lying baryon spectrum with two dynamical twisted mass fermions
International Nuclear Information System (INIS)
The masses of the low lying baryons are evaluated using two degenerate flavors of twisted mass sea quarks corresponding to pseudo scalar masses in the range of about 270 MeV to 500 MeV. The strange valence quark mass is tuned to reproduce the mass of the kaon in the physical limit. The tree-level Symanzik improved gauge action is employed. We use lattices of spatial size 2.1 fm and 2.7 fm at two values of the lattice spacing with r0/a=5.22(2) and r0/a=6.61(3). We check for both finite volume and cut-off effects on the baryon masses. We performed a detailed study of the chiral extrapolation of the octet and decuplet masses using SU(2) χPT. The lattice spacings determined using the nucleon mass at the physical point are consistent with the values extracted using the pion decay constant. We examine the issue of isospin symmetry breaking for the octet and decuplet baryons and its dependence on the lattice spacing. We show that in the continuum limit isospin breaking is consistent with zero, as expected. The baryon masses that we find after taking the continuum limit and extrapolating to the physical limit are in good agreement with experiment. (orig.)
International Nuclear Information System (INIS)
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 P11 (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 P11 (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
On the consistency of recent QCD lattice data of the baryon ground-state masses
Lutz, M F M
2012-01-01
In our recent analysis of lattice data of the BMW, LHPC and PACS-CS groups we determined a parameter set of the chiral Lagrangian that allows a simultaneous description of the baryon octet and decuplet masses as measured by those lattice groups. The results on the baryon spectrum of the HSC group were recovered accurately without their inclusion into our 6 parameter fit. We show that the same parameter set provides an accurate reproduction of the recent results of the QCDSF-UKQCD group probing the baryon masses at quite different quark masses. This shows a remarkable consistency amongst the different lattice simulations. With even more accurate lattice data in the near future it will become feasible to determine all low-energy parameters relevant at N$^3$LO.
The low-lying baryon spectrum with two dynamical twisted mass fermions
Alexandrou, C; Carbonell, J; Drach, V; Guichon, P; Jansen, K; Korzec, T; Pène, O
2009-01-01
The masses of the low lying baryons are evaluated using two degenerate flavors of twisted mass sea quarks corresponding to pseudo scalar masses in the range of about 270-500 MeV. The strange valence quark mass is tuned to reproduce the mass of the kaon in the physical limit. The tree-level Symanzik improved gauge action is employed. We use lattices of spatial size 2.1 fm and 2.7 fm at two values of the lattice spacing with $r_0/a=5.22(2)$ and $r_0/a=6.61(3)$. We check for both finite volume and cut-off effects on the baryon masses. We performed a detailed study of the chiral extrapolation of the octet and decuplet masses using SU(2) $\\chi$PT. The lattice spacings determined using the nucleon mass at the physical point are consistent with the values extracted using the pion decay constant. We examine the issue of isospin symmetry breaking for the octet and decuplet baryons and its dependence on the lattice spacing. We show that in the continuum limit isospin breaking is consistent with zero, as expected. The b...
Low lying baryon spectrum with N{sub f}=2+1+1 dynamical twisted quarks
Energy Technology Data Exchange (ETDEWEB)
Drach, Vincent; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Carbonell, Jaume; Papinutto, Mauro [UJF, CNRS/IN2P3, INPG (France). Lab. de Physique Subatomique et de Cosmologie; Alexandrou, Constantia [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics
2010-12-15
We present first results on the octet and decuplet strange baryon spectrum with N{sub f}=2+1+1 twisted mass quarks. We use an Osterwalder Seiler valence strange quark with a mass tuned to the kaon and compare the results with those obtained in the unitary setup. This comparison allows to perform a first study of the lattice artefacts introduced by the mixed action approach. We investigate the effect of the strange and charm quarks in the sea by using two lattice spacings and comparing with preceding N{sub f}=2 twisted mass fermion calculations. (orig.)
Low lying baryon spectrum with Nf=2+1+1 dynamical twisted quarks
International Nuclear Information System (INIS)
We present first results on the octet and decuplet strange baryon spectrum with Nf=2+1+1 twisted mass quarks. We use an Osterwalder Seiler valence strange quark with a mass tuned to the kaon and compare the results with those obtained in the unitary setup. This comparison allows to perform a first study of the lattice artefacts introduced by the mixed action approach. We investigate the effect of the strange and charm quarks in the sea by using two lattice spacings and comparing with preceding Nf=2 twisted mass fermion calculations. (orig.)
International Nuclear Information System (INIS)
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
Kaplunovsky, Vadim; Sonnenschein, Jacob
2012-01-01
In the large N limit cold dense nuclear matter must be in a lattice phase. This applies also to holographic models of hadron physics. In a class of such models, like the generalized Sakai-Sugimoto model, baryons take the form of instantons of the effective flavor gauge theory that resides on probe flavor branes. In this paper we study the phase structure of baryonic crystals by analyzing discrete periodic configurations of such instantons. We find that instanton configurations exhibit a series of "popcorn" transitions upon increasing the density. Through these transitions normal (3D) lattices expand into the transverse dimension, eventually becoming a higher dimensional (4D) multi-layer lattice at large densities. We consider 3D lattices of zero size instantons as well as 1D periodic chains of finite size instantons, which serve as toy models of the full holographic systems. In particular, for the finite-size case we determine solutions of the corresponding ADHM equations for both a straight chain and for a 2...
Kaplunovsky, Vadim; Melnikov, Dmitry; Sonnenschein, Jacob
2012-11-01
In the large N c limit cold dense nuclear matter must be in a lattice phase. This applies also to holographic models of hadron physics. In a class of such models, like the generalized Sakai-Sugimoto model, baryons take the form of instantons of the effective flavor gauge theory that resides on probe flavor branes. In this paper we study the phase structure of baryonic crystals by analyzing discrete periodic configurations of such instantons. We find that instanton configurations exhibit a series of "popcorn" transitions upon increasing the density. Through these transitions normal (3D) lattices expand into the transverse dimension, eventually becoming a higher dimensional (4D) multi-layer lattice at large densities. We consider 3D lattices of zero size instantons as well as 1D periodic chains of finite size instantons, which serve as toy models of the full holographic systems. In particular, for the finite-size case we determine solutions of the corresponding ADHM equations for both a straight chain and for a 2D zigzag configuration where instantons pop up into the holographic dimension. At low density the system takes the form of an "abelian anti- ferromagnetic" straight periodic chain. Above a critical density there is a second order phase transition into a zigzag structure. An even higher density yields a rich phase space characterized by the formation of multi-layer zigzag structures. The finite size of the lattices in the transverse dimension is a signal of an emerging Fermi sea of quarks. We thus propose that the popcorn transitions indicate the onset of the "quarkyonic" phase of the cold dense nuclear matter.
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...
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.
Yao, De-Liang; Siemens, D.; Bernard, V.; Epelbaum, E.; Gasparyan, A. M.; Gegelia, J.; Krebs, H.; Meißner, Ulf-G.
2016-05-01
We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S- and P -partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.
Relativistic chiral SU(3) symmetry, large Nc sum rules and meson-baryon scattering
International Nuclear Information System (INIS)
The relativistic chiral SU(3) Lagrangian is used to describe kaon-nucleon scattering imposing constraints from the pion-nucleon sector and the axial-vector coupling constants of the baryon octet states. We solve the covariant coupled-channel Bethe-Salpeter equation with the interaction kernel truncated at chiral order Q3 where we include only those terms which are leading in the large Nc limit of QCD. The baryon decuplet states are an important explicit ingredient in our scheme, because together with the baryon octet states they form the large Nc baryon ground states of QCD. Part of our technical developments is a minimal chiral subtraction scheme within dimensional regularization, which leads to a manifest realization of the covariant chiral counting rules. All SU(3) symmetry-breaking effects are well controlled by the combined chiral and large Nc expansion, but still found to play a crucial role in understanding the empirical data. We achieve an excellent description of the data set typically up to laboratory momenta of plab ≅ 500 MeV. (orig.)
International Nuclear Information System (INIS)
Experiments on strangeness production in nucleus-nucleus collisions at SIS energies address fundamental aspects of modern nuclear physics: the determination of the nuclear equation-of-state at high baryon densities and the properties of hadrons in dense nuclear matter. Experimental data and theoretical results will be reviewed. Future experiments at the FAIR accelerator aim at the exploration of the QCD phase diagram at highest baryon densities. The proposal for the Compressed Baryonic Matter (CBM) experiment will be presented. (author)
The Spectrum of the Baryon Masses in a Self-consistent SU(3) Quantum Skyrme Model
Jurciukonis, Darius; Regelskis, Vidas
2012-01-01
The semiclassical SU(3) Skyrme model is traditionally considered as describing a rigid quantum rotator with the profile function being fixed by the classical solution of the corresponding SU(2) Skyrme model. In contrast, we go beyond the classical profile function by quantizing the SU(3) Skyrme model canonically. The quantization of the model is performed in terms of the collective coordinate formalism and leads to the establishment of purely quantum corrections of the model. These new corrections are of fundamental importance. They are crucial in obtaining stable quantum solitons of the quantum SU(3) Skyrme model, thus making the model self-consistent and not dependent on the classical solution of the SU(2) case. We show that such a treatment of the model leads to a family of stable quantum solitons that describe the baryon octet and decuplet and reproduce the experimental values of their masses.
Spectroscopy of beautiful baryons
Energy Technology Data Exchange (ETDEWEB)
Caloi, R.; Gentile, S.; Mignani, R. (Rome Univ. (Italy). Ist. di Fisica)
1980-09-20
By assuming a non-relativistic quark model, an estimate of the masses of the low-lying (non-strange and non-charmed) beautiful baryons is given. Electromagnetic mass splittings of the same baryons are also discussed in some detail.
International Nuclear Information System (INIS)
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
Dipion decays of heavy baryons
International Nuclear Information System (INIS)
Compared with the charmed baryons, the bottom baryons are not known very well both experimentally and theoretically. In this paper, we investigate the dipion strong decays of the P-wave and D-wave excited bottom baryons in the framework of the QPC model. We also extend the same analysis to the charmed baryons
Indian Academy of Sciences (India)
Torsten Leddig
2012-11-01
From inclusive measurements, it is known that about 7% of all mesons decay into final states with baryons. In these decays, some striking features become visible compared to mesonic decays. The largest branching fractions come with quite moderate multiplicities of 3–4 hadrons. 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.
Indian Academy of Sciences (India)
Neetika Sharma; Harleen Dahiya
2013-02-01
The chiral constituent quark model ( CQM) with general parametrization (GP) method has been formulated to calculate the quadrupole moments of the spin $-\\dfrac{3}{2}^{+}$ decuplet baryons and spin $-\\dfrac{3}{2}^{+} → \\dfrac{1}{2}^{+}$ transitions. The implications of such a model have been investigated in detail for the effects of symmetry breaking and GP parameters pertaining to the two- and three-quark contributions. It is found that the CQM is successful in giving a quantitative and qualitative description of the quadrupole moments.
Photoproduction of hermaphrodite baryons
International Nuclear Information System (INIS)
We show 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. This is consistent with suggestions that the P11 (1710) is the lightest q3G baryon and eliminates the possibility of considerable mixing of q3G into the nucleon and delta's Fock space wavefunctions. (orig.)
International Nuclear Information System (INIS)
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 ΩB. 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 ΩB = 1 cosmological nucleosynthesis
Quark cluster model of baryon-baryon interaction
International Nuclear Information System (INIS)
The quark cluster model of the baryon-baryon interaction is reviewed. The emphasis is on the foundation of the approach and the main features of the model. The origins of the short-range repulsion in the nuclear force and other baryonic interactions are discussed. (author)
Supersymmetric Baryonic Branes
Gomis, J P; Simón, J; Townsend, P K; Gomis, Joaquim; Ramallo, Alfonso V.; Simon, Joan; Townsend, Paul K.
1999-01-01
We derive an energy bound for a `baryonic' D5-brane probe in the $adS_5\\times S^5$ background near the horizon of $N$ D3-branes. Configurations saturating the bound are shown to be 1/4 supersymmetric $S^5$-wrapped D5-branes with $N$ singularities at arbitrary positions. Previous results for $N$ coincident singularities are recovered as a special case. We derive a similar energy bound for a `baryonic' M5-brane probe in the background of $N$ M5-branes. Configurations saturating the bound are again 1/4 supersymmetric and, in the $adS_7\\times S^4$ near-horizon limit, provide a worldvolume realization of the `baryon string' vertex of the (2,0)-supersymmetric six-dimensional conformal field theory on coincident M5-branes. For the full M5-background we find a worldvolume realization of the Hannany-Witten effect in M-theory.
International Nuclear Information System (INIS)
Measurements of inclusive Λ + anti Λ production for 1.0 less than or equal to p less than or equal to 10.0 GeV/c and p + anti p production for 0.4 less than or equal to p less than or equal to 2.0 GeV/c show significant baryon production in e+e- annihilation at E/sub cm/ = 29 GeV. Λ + anti Λ production represents 0.2 Λ's or anti Λ's per PEP event while the observed p + anti p production implies all baryon-antibaryon pair production is occurring at least as often as 0.6 per event, depending on the yet to be measured p + anti p production at high momentum. Comparisons are made with the first theoretical attempts to account for baryon production at these energies
Charmed Bottom Baryon Spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Brown, Zachary S; Detmold, William; Meinel, Stefan; Orginos, Kostas
2014-11-01
The spectrum of doubly and triply heavy baryons remains experimentally unexplored to a large extent. Although the detection of such heavy particle states may lie beyond the reach of exper- iments for some time, it is interesting compute this spectrum from QCD and compare results between lattice calculations and continuum theoretical models. Several lattice calculations ex- ist for both doubly and triply charmed as well as doubly and triply bottom baryons. Here, we present preliminary results from the first lattice calculation of doubly and triply heavy baryons including both charm and bottom quarks. We use domain wall fermions for 2+1 flavors (up down and strange) of sea and valence quarks, a relativistic heavy quark action for the charm quarks, and non-relativistic QCD for the heavier bottom quarks. We present preliminary results for the ground state spectrum.
Photoproduction of hermaphrodite baryons
International Nuclear Information System (INIS)
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 P11(1710) is the lightest q3G 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 q3G into the nucleon and delta's Fock space wavefunctions. (author)
International Nuclear Information System (INIS)
Using state of the art lattice techniques we investigate the static baryon potential. We employ the multi-hit procedure for the time links and a variational approach to determine the ground state with sufficient accuracy that, for distances up to ∼ 1.2 fm, we can distinguish the Y- and Δ- Ansaetze for the baryonic Wilson area law. Our analysis shows that the Δ-Ansatz is favoured. This result is also supported by the gauge-invariant nucleon wave function which we measure for the first time
Liu, Keh-Fei
2016-01-01
The relevance of chiral symmetry in baryons is highlighted in three examples in the nucleon spectroscopy and structure. The first one is the importance of chiral dynamics in understanding the Roper resonance. The second one is the role of chiral symmetry in the lattice calculation of $\\pi N \\sigma$ term and strangeness. The third one is the role of chiral $U(1)$ anomaly in the anomalous Ward identity in evaluating the quark spin and the quark orbital angular momentum. Finally, the chiral effective theory for baryons is discussed.
Baryon masses at second order in large-N chiral perturbation theory
International Nuclear Information System (INIS)
We consider flavor breaking in the octet and decuplet baryon masses at second order in large-N chiral perturbation theory, where N is the number of QCD colors. We assume that 1/N∼1/NF∼ms/Λ>mu,d/Λ,αEM, where NF is the number of light quark flavors, and mu,d,s/Λ are the parameters controlling SU(NF) flavor breaking in chiral perturbation theory. We consistently include nonanalytic contributions to the baryon masses at orders mq3/2, m2qlnmq, and (mqlnmq)/N. The mq3/2 corrections are small for the relations that follow from SU(NF) symmetry alone, but the corrections to the large-N relations are large and have the wrong sign. Chiral power counting and large-N consistency allow a two-loop contribution at order m2qlnmq, and a nontrivial explicit calculation is required to show that this contribution vanishes. At second order in the expansion, there are eight relations that are nontrivial consequences of the 1/N expansion, all of which are well satisfied within the experimental errors. The average deviation at this order is 7 MeV for the ΔI=0 mass differences and 0.35 MeV for the ΔI≠0 mass differences, consistent with the expectation that the error is of order 1/N2∼10%. copyright 1996 The American Physical Society
Electroproduction of light quark baryons
International Nuclear Information System (INIS)
The status of electromagnetic excitation of light quark (u, d) baryon states is reviewed and confronted with results of calculations within the framework of microscopic models of the baryon structure and the photon-baryon coupling. Prospects for a qualitative improvement of our knowledge in this sector using photon and electron beams at the new, intermediate energy continuous wave electron machines are discussed
Babu, K S; Al-Binni, U; Banerjee, S; Baxter, D V; Berezhiani, Z; Bergevin, M; Bhattacharya, S; Brice, S; Brock, R; Burgess, T W; Castellanos, L; Chattopadhyay, S; Chen, M-C; Church, E; Coppola, C E; Cowen, D F; Cowsik, R; Crabtree, J A; Davoudiasl, H; Dermisek, R; Dolgov, A; Dutta, B; Dvali, G; Ferguson, P; Perez, P Fileviez; Gabriel, T; Gal, A; Gallmeier, F; Ganezer, K S; Gogoladze, I; Golubeva, E S; Graves, V B; Greene, G; Handler, T; Hartfiel, B; Hawari, A; Heilbronn, L; Hill, J; Jaffe, D; Johnson, C; Jung, C K; Kamyshkov, Y; Kerbikov, B; Kopeliovich, B Z; Kopeliovich, V B; Korsch, W; Lachenmaier, T; Langacker, P; Liu, C-Y; Marciano, W J; Mocko, M; Mohapatra, R N; Mokhov, N; Muhrer, G; Mumm, P; Nath, P; Obayashi, Y; Okun, L; Pati, J C; Pattie, R W; Phillips, D G; Quigg, C; Raaf, J L; Raby, S; Ramberg, E; Ray, A; Roy, A; Ruggles, A; Sarkar, U; Saunders, A; Serebrov, A; Shafi, Q; Shimizu, H; Shiozawa, M; Shrock, R; Sikdar, A K; Snow, W M; Soha, A; Spanier, S; Stavenga, G C; Striganov, S; Svoboda, R; Tang, Z; Tavartkiladze, Z; Townsend, L; Tulin, S; Vainshtein, A; Van Kooten, R; Wagner, C E M; Wang, Z; Wehring, B; Wilson, R J; Wise, M; Yokoyama, M; Young, A R
2013-01-01
This report, prepared for the Community Planning Study - Snowmass 2013 - summarizes the theoretical motivations and the experimental efforts to search for baryon number violation, focussing on nucleon decay and neutron-antineutron oscillations. Present and future nucleon decay search experiments using large underground detectors, as well as planned neutron-antineutron oscillation search experiments with free neutron beams are highlighted.
International Nuclear Information System (INIS)
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.)
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.
Paolis, F.; Ingrosso, G.; Jetzer, Ph.; 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.
Photoproduction of charmed baryons
International Nuclear Information System (INIS)
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 K0. The cross section times branching ratio of γ + C → Λ/sub c/+ + X, γ + C → p + anti K0 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/c2, in good agreement with the Mark II result from SPEAR. Upper limits (90% confidence level) are set on sigma B for the modes Λ0π, Λ0πππ, pKπ
Energy Technology Data Exchange (ETDEWEB)
Buccella, F.; Farrar, G.R.; Rutgers - the State Univ., New Brunswick, NJ; Pugliese, A.
1985-04-04
The MIT bag model is used to calculate masses of (R-)baryons, composed of three quarks and a gluino. If the gluino mass is small, the lightest of these, a flavor singlet, could be long-lived or even absolutely stable. The next lighest, the R-nucleons, probably have only weak decays, while all others are likely to decay strongly. This physical picture is not ruled out experimentally. (orig.).
Energy Technology Data Exchange (ETDEWEB)
Buccella, F.; Farrar, G.R.; Pugliese, A.
1985-04-04
The MIT bag model is used to calculate masses of (R-)baryons, composed of three quarks and a gluino. If the gluino mass is small, the lightest of these, a flavor singlet, could be long-lived or even absolutely stable. The next lighest, the R-nucleons, probably have only weak decays, while all others are likely to decay strongly. This physical picture is not ruled out experimentally.
International Nuclear Information System (INIS)
The MIT bag model is used to calculate masses of (R-)baryons, composed of three quarks and a gluino. If the gluino mass is small, the lightest of these, a flavor singlet, could be long-lived or even absolutely stable. The next lighest, the R-nucleons, probably have only weak decays, while all others are likely to decay strongly. This physical picture is not ruled out experimentally. (orig.)
CP Violating Baryon Oscillations
McKeen, David; Nelson, Ann E.
2015-01-01
We analyze neutron-antineutron oscillation in detail, developing a Hamiltonian describing the system in the presence of electromagnetic fields. While magnetic fields can couple states of different spin, we show that, because of Fermi statistics, this coupling of different spin states does not involve baryon-number--changing transitions and, therefore, a two-state analysis ignoring spin is sufficient even in the presence of electromagnetic fields. We also enumerate the conditions necessary for...
Reconstructing baryon oscillations
Noh, Yookyung; White, Martin; Padmanabhan, Nikhil
2009-01-01
The baryon acoustic oscillation (BAO) method for constraining the expansion history is adversely affected by non-linear structure formation, which washes out the correlation function peak created at decoupling. To increase the constraining power of low z BAO experiments, it has been proposed that one use the observed distribution of galaxies to "reconstruct'' the acoustic peak. Recently Padmanabhan, White and Cohn provided an analytic formalism for understanding how reconstruction works withi...
Strangeness S = -3 and -4 baryon-baryon interactions in chiral EFT
International Nuclear Information System (INIS)
I report on recent progress in the description of baryon-baryon systems within chiral effective field theory. In particular, I discuss results for the strangeness S = -3 to -4 baryon-baryon systems, obtained to leading order.
Baryon spectroscopy in lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Derek B. Leinweber; Wolodymyr Melnitchouk; David Richards; Anthony G. Williams; James Zanotti
2004-04-01
We review recent developments in the study of excited baryon spectroscopy in lattice QCD. After introducing the basic methods used to extract masses from correlation functions, we discuss various interpolating fields and lattice actions commonly used in the literature. We present a survey of results of recent calculations of excited baryons in quenched QCD, and outline possible future directions in the study of baryon spectra.
Chiral dynamics and baryon resonances
Hyodo, Tetsuo
2010-01-01
The structure of baryon resonance in coupled-channel meson-baryon scattering is studied from the viewpoint of chiral dynamics. The meson-baryon scattering amplitude can be successfully described together with the properties of the resonance in the scattering, by implementing the unitarity condition for the amplitude whose low energy structure is constrained by chiral theorem. Recently, there have been a major progress in the study of the structure of the resonance in chiral dynamics. We revie...
Nawa, K; Suganuma, H; Kojo, Toru; Nawa, Kanabu; Suganuma, Hideo
2006-01-01
We study the baryon in holographic QCD with $D4/D8/\\bar{D8}$ multi-$D$ brane system. In holographic QCD, the baryon appears as a topologically non-trivial chiral soliton in a four-dimensional effective theory of mesons. We call this topological soliton as Brane-induced Skyrmion. Some review of $D4/D8/\\bar{D8}$ holographic QCD is presented from the viewpoints of recent hadron physics and phenomenologies. Four-dimensional effective theory with pions and $\\rho$ mesons is uniquely derived from the non-abelian Dirac-Born-Infeld (DBI) action of $D8$ brane with $D4$ supergravity background, without small amplitude expansion of meson fields to discuss chiral solitons. For the hedgehog configuration of pion and $\\rho$-meson fields, we derive the energy functional and the Euler-Lagrange equation of Brane-induced Skyrmion from the meson effective action induced by holographic QCD. Performing the numerical calculation, we obtain the pion profile $F(r)$ and the $\\rho$-meson profile $G(r)$ of the Brane-induced Skyrmion, an...
Dynamically generated baryon resonances
Lutz, M F M
2005-01-01
Identifying a zero-range exchange of vector mesons as the driving force for the s-wave scattering of pseudo-scalar mesons off the baryon ground states, a rich spectrum of molecules is formed. We argue that chiral symmetry and large-$N_c$ considerations determine that part of the interaction which generates the spectrum. We suggest the existence of strongly bound crypto-exotic baryons, which contain a charm-anti-charm pair. Such states are narrow since they can decay only via OZI-violating processes. A narrow nucleon resonance is found at mass 3.52 GeV. It is a coupled-channel bound state of the $(\\eta_c N), (\\bar D \\Sigma_c)$ system, which decays dominantly into the $(\\eta' N)$ channel. Furthermore two isospin singlet hyperon states at mass 3.23 GeV and 3.58 GeV are observed as a consequence of coupled-channel interactions of the $(\\bar D_s \\Lambda_c), (\\bar D \\Xi_c)$ and $(\\eta_c \\Lambda),(\\bar D \\Xi_c')$ states. Most striking is the small width of about 1 MeV of the lower state. The upper state may be signi...
Baryon Production in the String Fragmentation Picture
Eden, Patrik; Gustafson, Gosta
1996-01-01
An improved version of the ``pop-corn'' model for baryon production in quark and gluon jets is presented. With a reduced number of parameters the model reproduces well both production rates for different baryon species and baryon momentum distributions. Predictions are presented for a set of baryon-antibaryon correlations.
Decay and spectra of baryons especially beauty baryons
Kalman, C. S.
1996-06-01
Masses and decays of the baryons are considered. The entire spectroscopy of baryons containing u,d,s,c and b quarks is calculated using the five quark masses and only four additional parameters describing the potential between the baryons. This potential is taken to be a short-range Coulomb potential together with a long-range linear potential modified by a harmonic-oscillator potential. Decays are studied using the quark pair creation model of Le Yaouanc et. al. The pair strength γ is replaced by kγ . This and the meson radius are the only parameters used in the calculation of the decays. Overall, we have a useful model, employing a small number of parameters, yet capable of yielding a description of the baryons in good accord with experimental data.
Baryon asymmetry in inflationary universe
International Nuclear Information System (INIS)
The problem of the baryon asymmetry in inflationary universe is discussed. It is shown that the baryon asymmetry in inflationary universe under certain constrainsts on masses of superheavy bosons can be larger than that in the standard scenario. An important property of the model considered is that the final baryon asymmetry does not depend on initial conditions in the early universe in contrast to what occUrs in the standard scenario based on (B-L) conserving grand unified theories. The new scenario is realized in the framework of the SU(5) Coleman-Weinberg theory with the symmetry breaking
Baryon mapping of quark systems
Sambataro, M
1995-01-01
We discuss a mapping procedure from a space of colorless three-quark clusters into a space of elementary baryons and illustrate it in the context of a three-color extension of the Lipkin model recently developed. Special attention is addressed to the problem of the formation of unphysical states in the mapped space. A correspondence is established between quark and baryon spaces and the baryon image of a generic quark operator is defined both in its Hermitian and non-Hermitian forms. Its spectrum (identical in the two cases) is found to consist of a physical part containing the same eigenvalues of the quark operator in the cluster space and an unphysical part consisting only of zero eigenvalues. A physical subspace of the baryon space is also defined where the latter eigenvalues are suppressed. The procedure discussed is quite general and applications of it can be thought also in the correspondence between systems of 2n fermions and n bosons.
Baryon Instability in SUSY Models
Nath, Pran; Arnowitt, R.
1996-01-01
Comment: 14 pages, latex, 1 fig, to be published in proceedings of the International Workshop on " Future Prospects of Baryon Instability Search in p-Decay and n-nbar Oscillation Experiments", Oak Ridge, Tennessee, March 28-30,1996
Excitations of strange bottom baryons
Woloshyn, R M
2016-01-01
The ground state and first excited state masses of Omega(b) and Omega(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.
Baryonic Operators for Lattice Simulations
Edwards, R; Fleming, G; Heller, U M; Morningstar, C J; Richards, D; Sato, I; Wallace, S
2004-01-01
The construction of baryonic operators for determining the N* excitation spectrum is discussed. The operators are designed with one eye towards maximizing overlaps with the low-lying states of interest, and the other eye towards minimizing the number of sources needed in computing the required quark propagators. Issues related to spin identification are outlined. Although we focus on tri-quark baryon operators, the construction method is applicable to both mesons and penta-quark operators.
Anomalous Dimensions of Conformal Baryons
Pica, Claudio
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 for a wide range of number of flavours. We also find that this is always smaller than the anomalous dimension of the fermion mass operator. These findings challenge the partial compositeness paradigm.
Galaxy Cluster Baryon Fractions Revisited
Gonzalez, Anthony H; Zabludoff, Ann I; Zaritsky, Dennis
2013-01-01
We measure the baryons contained in both the stellar and hot gas components for twelve galaxy clusters and groups at z~0.1 with M=1-5e14 Msun. This paper improves upon our previous work through the addition of XMM data, enabling measurements of the total mass and masses of each major baryonic component --- ICM, intracluster stars, and stars in galaxies --- for each system. We recover a relation for the stellar mass versus halo mass consistent with our previous result. We confirm that the partitioning of baryons between the stellar and hot gas components is a strong function of M500; the fractions of total mass in stars and X-ray gas within r500 scale as M500^-0.45 and M500^0.26, respectively. We also confirm that the combination of the BCG and intracluster stars is an increasingly important contributor to the stellar baryon budget in lower halo masses. We find a weak, but statistically significant, dependence of the total baryon fraction upon halo mass, scaling as M500^0.16. For M500>2e14, the total baryon fr...
Baryons and baryonic matter in four-fermion interaction models
International Nuclear Information System (INIS)
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
Galaxy cluster baryon fractions revisited
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, Anthony H. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Sivanandam, Suresh; Zabludoff, Ann I.; Zaritsky, Dennis [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
2013-11-20
We measure the baryons contained in both the stellar and hot-gas components for 12 galaxy clusters and groups at z ∼ 0.1 with M = 1-5 × 10{sup 14} M {sub ☉}. This paper improves upon our previous work through the addition of XMM-Newton X-ray data, enabling measurements of the total mass and masses of each major baryonic component—intracluster medium, intracluster stars, and stars in galaxies—for each system. We recover a mean relation for the stellar mass versus halo mass, M{sub ⋆}∝M{sub 500}{sup −0.52±0.04}, that is 1σ shallower than in our previous result. We confirm that the partitioning of baryons between the stellar and hot-gas components is a strong function of M {sub 500}; the fractions of total mass in stars and X-ray gas within a sphere of radius r {sub 500} scale as f{sub ⋆}∝M{sub 500}{sup −0.45±0.04} and f{sub gas}∝M{sub 500}{sup 0.26±0.03}, respectively. We also confirm that the combination of the brightest cluster galaxy and intracluster stars is an increasingly important contributor to the stellar baryon budget in lower halo masses. Studies that fail to fully account for intracluster stars typically underestimate the normalization of the stellar baryon fraction versus M {sub 500} relation by ∼25%. Our derived stellar baryon fractions are also higher, and the trend with halo mass weaker, than those derived from recent halo occupation distribution and abundance matching analyses. One difference from our previous work is the weak, but statistically significant, dependence here of the total baryon fraction upon halo mass: f{sub bary}∝M{sub 500}{sup 0.16±0.04}. For M {sub 500} ≳ 2 × 10{sup 14}, the total baryon fractions within r {sub 500} are on average 18% below the universal value from the seven year Wilkinson Microwave Anisotropy Probe (WMAP) analysis, or 7% below for the cosmological parameters from the Planck analysis. In the latter case, the difference between the universal value and cluster baryon fractions is
Baryon Transition in Holographic QCD
Li, Siwen
2015-01-01
We propose a mechanism of holographic baryon transition in the Sakai-Sugimoto (SS) model: baryons in this model can jump to different states under the mediated effect of gravitons (or glueballs by holography). We consider a time-dependent gravitational perturbation from M5-brane solution of D=11 supergravity and by employing the relations between 11D M-theory and IIA string theory, we get its 10 dimensional counterpart in the SS model. Such a perturbation is received by the D4-branes wrapped on the $S^{4}$ part of the 10D background, namely the baryon vertex. Technically, baryons in the SS model are described by BPST instanton ansatz and their dynamics can be analyzed using the quantum mechanical system in the instanton's moduli space. In this way, different baryonic states are marked by quantum numbers of moduli space quantum mechanics. By holographic spirit, the gravitational perturbation enters the Hamiltonian as a time-dependent perturbation and it is this time-dependent perturbative Hamiltonian produces ...
Kalashnikova, Yu S
1996-01-01
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 the baryon in comparison with the standard potential picture. We discuss the effects of the 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 and leaving room to the short range Coulomb force in...
The question of baryon conservation
International Nuclear Information System (INIS)
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)
Deforming baryons into confining strings
Hartnoll, S A; Hartnoll, Sean A.; Portugues, Ruben
2004-01-01
We find explicit probe D3-brane solutions in the infrared of the Maldacena-Nunez background. The solutions describe deformed baryon vertices: q external quarks are separated in spacetime from the remaining N-q. As the separation is taken to infinity we recover known solutions describing infinite confining strings in ${\\mathcal{N}}=1$ gauge theory. We present results for the mass of finite confining strings as a function of length. We also find probe D2-brane solutions in a confining type IIA geometry, the reduction of a G_2 holonomy M theory background. The interpretation of these solutions as deformed baryons/confining strings is not as straightforward.
Heavy Baryons and Exotics Spectrum
Karliner, Marek; Tornqvist, Nils A
2011-01-01
We discuss several highly accurate theoretical predictions for masses of baryons containing the b quark which have been recently confirmed by experimental data. Several predictions are given for additional properties of heavy baryons. We also discuss the two charged exotic resonances Z_b with quantum numbers of a (b bbar u ddbar) tetraquark, very recently reported by Belle in the channel [Upsilon(nS) \\pi^+, n=1,2,3]. Among possible implications are deeply bound I=0 counterparts of the Z_b-s and existence of a Sigma_b^+ Sigma_b^- dibaryon, a "beauteron".
Baryonic spectroscopy and its immediate future
International Nuclear Information System (INIS)
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
Baryon Resonance Analysis from SAID
Arndt, R A; Paris, M W; Strakovsky, I I; Workman, R L
2009-01-01
We discuss the analysis of data from piN elastic scattering and single pion photo- and electroproduction. The main focus is a study of low-lying non-strange baryon resonances. Here we concentrate on some difficulties associated with resonance identification, in particular the Roper and higher P11 states.
Magnetic monopoles and baryon decay
International Nuclear Information System (INIS)
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)
Alternative large Nc baryons and holography
International Nuclear Information System (INIS)
In gauge theories in the limit of a large number Nc of colors baryons are usually described as heavy solitonic objects with mass of order Nc. We discuss an alternative large Nc description both directly in the field theory as well as using holography. In this alternative large Nc limit at least some of the baryons behave like mesons, that is they stay light even at large Nc and their interactions vanish in that limit. For Nc=3 these alternative large Nc baryons are equivalent to the standard baryons. In the holographic description it is manifest that the Regge slopes of mesons and alternative baryons are degenerate.
Alternative large Nc baryons and holography
Hoyos-Badajoz, Carlos
2009-01-01
In gauge theories in the limit of a large number Nc of colors, baryons are usually described as heavy solitonic objects with mass of order Nc. We discuss an alternative large Nc description both directly in the field theory as well as using holography. In this alternative large Nc limit at least some of the baryons behave like mesons, that is they stay light even at large Nc and their interactions vanish in that limit. For Nc=3 these alternative large Nc baryons are equivalent to the standard baryons. In the holographic description it is manifest that the Regge slopes of mesons and alternative baryons are degenerate.
Heavy baryon production and decay
International Nuclear Information System (INIS)
The branching ratio B(Λc→pK-π+) normalizes the production and decay of charmed and bottom baryons. At present, this crucial branching ratio is extracted dominantly from bar B→baryons analyses. This paper questions several of the underlying assumptions and predicts sizable bar B→D(*)N bar N'X transitions, which were traditionally neglected. It predicts B(Λc→pK-π+) to be larger (0.07±0.02) than the world average. Some consequences are briefly mentioned. Several techniques to measure B(Λc→pK-π+) are outlined with existing or soon available data samples. By equating two recent CLEO results, an appendix obtains B(D0→K-π+)=0.035±0.002, which is somewhat smaller than the current world average. copyright 1998 The American Physical Society
Bergstrom, L.
2001-01-01
The need for dark matter is briefly reviewed. A wealth of observational information points to the existence of a non-baryonic component. To the theoretically favoured candidates today belong axions, supersymmetric particles, and to some extent massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. In particular, indirect detection methods of supersymmetric dark matter are described. Present experiments are just reaching the required sensitivity...
Baryons and Mesons with Beauty
Goldstein, Gary R.; Wali, Kameshwar C.
2007-01-01
Recent experimental findings of several mesons and baryons with "beauty" and "charm" as flavors remind us of the days when strangeness was discovered, and how its inclusion led to SU(3)-flavor symmetry with enormous success in the classification of the "proliferated" states into SU(3) multiplets. One of the key elements was the successful application of the first order perturbation in symmetry breaking, albeit what then appeared to be huge mass differences, and the prediction of new states th...
Transport coefficients of heavy baryons
Tolos, Laura; Torres-Rincon, Juan M.; Das, Santosh K.
2016-08-01
We compute the transport coefficients (drag and momentum diffusion) of the low-lying heavy baryons Λc and Λb in a medium of light mesons formed at the later stages of high-energy heavy-ion collisions. We employ the Fokker-Planck approach to obtain the transport coefficients from unitarized baryon-meson interactions based on effective field theories that respect chiral and heavy-quark symmetries. We provide the transport coefficients as a function of temperature and heavy-baryon momentum, and analyze the applicability of certain nonrelativistic estimates. Moreover we compare our outcome for the spatial diffusion coefficient to the one coming from the solution of the Boltzmann-Uehling-Uhlenbeck transport equation, and we find a very good agreement between both calculations. The transport coefficients for Λc and Λb in a thermal bath will be used in a subsequent publication as input in a Langevin evolution code for the generation and propagation of heavy particles in heavy-ion collisions at LHC and RHIC energies.
International Nuclear Information System (INIS)
The QCD-motivated constituent string model is extended to consider the baryon. The system of three quarks propagating in a 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. Under the assumption that quarks are sufficiently heavy to allow the adiabatic separation of quark and string-junction motions, the use of hyperspherical expansion for the quark subsystem makes it possible to write and solve the classical equation of motion for the junction. The motion of the junction is quantized, and it is shown that the effective ''swelling'' of the baryon in relation to the standard potential picture occurs as the result of taking these modes into account. Effects associated with a finite gluon-correlation length, which do not affect excited states, but which appear to be substantial for the baryon ground state, reducing the ''swelling'' considerably and leaving room to the short-range Coulomb force in the three-quark system, are discussed
Faddeev study of heavy baryon spectroscopy
Garcilazo, H; Vijande, J
2007-01-01
We investigate the structure of heavy baryons containing a charm or a bottom quark. We employ a constituent quark model successful in the description of the baryon-baryon interaction which is consistent with the light baryon spectra. We solve exactly the three-quark problem by means of the Faddeev method in momentum space. Heavy baryon spectrum shows a manifest compromise between perturbative and nonperturbative contributions. The flavor dependence of the one-gluon exchange is analyzed. We assign quantum numbers to some already observed resonances and we predict the first radial and orbital excitations of all states with $J=1/2$ or 3/2. We combine our results with heavy quark symmetry and lowest-order SU(3) symmetry breaking to predict the masses and quantum numbers of six still non-measured ground-state beauty baryons.
The Heavy Baryon Physics by means LEP
International Nuclear Information System (INIS)
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)
Baryon Asymmetry, Inflation and Squeezed States
Bambah, Bindu A.; Chaitanya, K. V. S. Shiv; Mukku, C.
2006-01-01
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 anti-particle modes gives rise to baryon asymmetry.
Hadronic molecules in the heavy baryon spectrum
International Nuclear Information System (INIS)
We study possible baryon molecules in the non-strange heavy baryon spectrum. We include configurations with a heavy-meson and a light baryon. We find several structures, in particular we can understand the Λc(2940) as a D*N molecule with JP = 3/2− quantum numbers. We also find D(*)Δ candidates for the recently discovered Xc(3250) resonance
Baryons with Two Heavy Quarks as Solitons
Bander, Myron; Subbaraman, Anand
1994-01-01
Using the chiral soliton model and heavy quark symmetry we study baryons containing two heavy quarks. If there exists a stable (under strong interactions) meson consisting of two heavy quarks and two light ones, then we find that there always exists a state of this meson bound to a chiral soliton and to a chiral anti-soliton, corresponding to a two heavy quark baryon and a baryon containing two heavy anti-quarks and five light quarks, or a ``heptaquark".
CP violation with beautiful baryons
Energy Technology Data Exchange (ETDEWEB)
Dunietz, I. (European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.)
1992-10-01
CP violation can be studied in modes of charmed or bottom baryons when a decay process is compared with its charge-conjugated partner. It can show up as a rate asymmetry and in a study of other decay parameters. Neither tagging nor time-dependences are required to observe CP violation with modes of baryons, in contrast to the conventional B{sup 0} modes. Numerous modes of bottom baryons have the potential to show large CP-violating effects within the Standard Model. Those effects can be substantial for modes with a D{sup 0}, which is seen in a final state that can also be fed from {anti D}{sup 0}. For instance, a comparison of the {Lambda}{sub b}{yields}{Lambda}D{sub CP}{sup 0} with the anti {Lambda}{sub b}{yields} anti {Lambda}D{sub CP}{sup 0} process can show sizeable CP violation. Here D{sub CP}{sup 0} denotes CP eigenstates of D{sup 0}, which occur at a few percent. Six related processes, such as {Lambda}{sub b}{yields}{Lambda}D{sup 0}, {Lambda}{sub b}{yields}{Lambda}{anti D}{sup 0}, {Lambda}{sub b}{yields}{Lambda}D{sub CP}{sup 0}, and their charge-conjugated counterparts, can extract {phi}, which is the most problematic angle of the unitarity triangle and which is conventionally probed with the B{sub s}{yields}{rho}{sup 0} K{sub S} asymmetry. Here D{sup 0} and anti D{sup 0} are identified by their charged kaon or lepton.
Doubly Heavy Tetraquarks and Baryons
Directory of Open Access Journals (Sweden)
Karliner Marek
2014-04-01
Full Text Available During the last three years strong experimental evidence from B and charm factories has been accumulating for the existence of exotic hadronic quarkonia, narrow resonances which cannot be made from a quark and an antiquark. Their masses and decay modes show that they contain a heavy quark-antiquark pair, but their quantum numbers are such that they must also contain a light quark-antiquark pair. The theoretical challenge has been to determine the nature of these resonances. The main possibilities are that they are either "genuine tetraquarks", i.e. two quarks and two antiquarks within one confinement volume, or "hadronic molecules" of two heavy-light mesons. In the last few months there as been more and more evidence in favor of the latter. I discuss the experimental data and its interpretation and provide fairly precise predictions for masses and quantum numbers of the additional exotic states which are naturally expected in the molecular picture but have yet to be observed. In addition, I provide arguments in favor of the existence of an even more exotic state – a hypothetical deuteron-like bound state of two heavy baryons. I also consider “baryon-like" states QQ' q¯q¯′$\\bar q\\bar q\\prime $, which if found will be direct evidence not just for near-threshold binding of two heavy mesons, but for genuine tetraquarks with novel color networks. I stress the importance of experimental search for doubly-heavy baryons in this context.
Quarks, baryons and chiral symmetry
Hosaka, Atsushi
2001-01-01
This book describes baryon models constructed from quarks, mesons and chiral symmetry. The role of chiral symmetry and of quark model structure with SU(6) spin-flavor symmetry are discussed in detail, starting from a pedagogic introduction. Emphasis is placed on symmetry aspects of the theories. As an application, the chiral bag model is studied for nucleon structure, where important methods of theoretical physics, mostly related to the semiclassical approach for a system of strong interactions, are demonstrated. The text is more practical than formal; tools and ideas are explained in detail w
Bergström, L
1999-01-01
The need for dark matter is briefly reviewed. A wealth of observational information points to the existence of a non-baryonic component. To the theoretically favoured candidates today belong axions, supersymmetric particles, and to some extent massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. In particular, indirect detection methods of supersymmetric dark matter are described. Present experiments are just reaching the required sensitivity to discover or rule out some of these candidates, and major improvements are planned over the next few years.
International Nuclear Information System (INIS)
The need for dark matter is briefly reviewed. A wealth of observational information points to the existence of a non-baryonic component. To the theoretically favoured candidates today belong axions, supersymmetric particles, and to some extent massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. In particular, indirect detection methods of supersymmetric dark matter are described. Present experiments are just reaching the required sensitivity to discover or rule out some of these candidates, and major improvements are planned over the next few years
Beautiful Baryons from Lattice QCD
Alexandrou, C.; Borrelli, A; Güsken, S.; Jegerlehner, F.; K. Schilling; Siegert, G.; Sommer, R
1994-01-01
We perform a lattice study of heavy baryons, containing one ($\\Lambda_b$) or two $b$-quarks ($\\Xi_b$). Using the quenched approximation we obtain for the mass of $\\Lambda_b$ $$ M_{\\Lambda_b}= 5.728 \\pm 0.144 \\pm 0.018 {\\rm GeV}.$$ The mass splitting between the $\\Lambda_b$ and the B-meson is found to increase by about 20\\% if the light quark mass is varied from the chiral limit to the strange quark mass.
Baryon Form Factors at Threshold
Energy Technology Data Exchange (ETDEWEB)
Baldini Ferroli, Rinaldo [Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' , Rome (Italy); INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Pacetti, Simone [INFN and Dipartimento di Fisica, Universita di Perugia, Perugia (Italy)
2012-04-15
An extensive study of the e{sup +}e{sup -}{yields}pp{sup Macron }BABAR cross section data is presented. Two unexpected outcomes have been found: the modulus of the proton form factor is normalized to one at threshold, i.e.: |G{sup p}(4M{sub p}{sup 2})|=1, as a pointlike fermion, and the resummation factor in the Sommerfeld formula is not needed. Other e{sup +}e{sup -} {yields} baryon-antibaryon cross sections show a similar behavior near threshold.
The good, the bad, and the baryon
International Nuclear Information System (INIS)
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 spectroscopy and the omega minus
International Nuclear Information System (INIS)
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
Octet-baryon masses in finite space
Ren, Xiu-Lei; Geng, Lisheng; Meng, Jie
2012-01-01
We report on a recent study of finite-volume effects on the lowest-lying octet baryon masses using the covariant baryon chiral perturbation theory up to next-to-leading order by analysing the latest $n_f = 2 + 1$ lattice QCD results from the NPLQCD Collaboration.
Heavy baryons in the relativistic quark model
International Nuclear Information System (INIS)
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 JP=1/2+, 3/2+ are computed. (orig.)
Domain walls. II. Baryon-number generation
International Nuclear Information System (INIS)
Domain walls present in the early universe due to a spontaneous breakdown of charge conjugation can leave behind net baryon number. SU/sub R/(2) instantons provide baryon nonconservation and the proton is effectively stable. Density perturbations (on scales large enough for galaxy formation) and monopole suppression can occur if walls dominate the energy density. Mechanisms for wall removal are discussed
Exploring the simplest purely baryonic decay processes
Geng, C Q; Rodrigues, Eduardo
2016-01-01
We propose to search for purely baryonic decay processes at the LHCb experiment. In particular, we concentrate on the decay $\\Lambda_b^0\\to p\\bar pn$, which is the simplest purely baryonic decay mode, with solely spin-1/2 baryons involved. We predict its decay branching ratio to be ${\\cal B}(\\Lambda_b^0\\to p\\bar pn)=(2.0^{+0.3}_{-0.2})\\times 10^{-6}$, which is sufficiently large to make the decay mode accessible to LHCb. Though not considered in general, purely baryonic decays could shed light on the puzzle of the baryon number asymmetry in the universe by means of a better understanding of the baryonic nature of our matter world. As such, they constitute a yet unexplored class of decay processes worth investigating. Our study can be extended to the purely baryonic decays of $\\Lambda_b^0\\to p\\bar p \\Lambda$, $\\Lambda_b^0\\to \\Lambda \\bar p\\Lambda$ and $\\Lambda_b^0\\to \\Lambda\\bar \\Lambda\\Lambda$, as well as other similar anti-triplet $b$-baryon decays, such as $\\Xi_b^{0,-}$.
Energy Technology Data Exchange (ETDEWEB)
Frishman, Y. (Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Physics); Zakrzewski, W.J. (Durham Univ. (UK). Dept. of Mathematical Siences)
1989-12-18
We find multi-baryon states in two-dimensional quantum chromodynamics. We show that to bind two baryons the model must involve at least seven flavours. All calculations are performed in the strong coupling limit and the semiclassical approximation is employed in the derivation of the results. We briefly comment on the properties of the derived states. (orig.).
Baryonic masses based on the NJL model
International Nuclear Information System (INIS)
We employ the Nambu-Jona-Lasinio model to determine the vacuum pressure on the quarks in a baryon and hence their density inside. Then we estimate the baryonic masses by implementing the local density approximation for the mean-field quark energies obtained in a uniform and isotropic system. We obtain a fair agreement with the experimental masses. (orig.)
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.
Electromagnetic structure of octet baryons
International Nuclear Information System (INIS)
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. General forms of the baryon interpolating fields are considered. Magnetic moments, electric radii, magnetic radii, and magnetic transition moments are extracted from the form factors. The electric properties are found to be consistent with a quark-model picture involving spin-dependent forces. The lattice results for the magnetic properties show a mass and spin dependence of the effective quark moments which is not accounted for in conventional quark models. Lattice calculations underestimate the magnitude of electric radii, magnetic radii, and magnetic moments compared to experimental measurements. The finite volume of the periodic lattice may be responsible for the discrepancies. The pattern of electromagnetic radii in the lattice results are seen to be generally reproduced in the model results that are considered. The only exception is that of Ξ- which proves to be a sensitive probe of the quark dynamics. Lattice calculations indicate a positive value for the normalized square magnetic radius in Ξ- which contrasts Skyrme model results. Ratios of the magnetic moments allow a more detailed comparison with the experimental measurements. The lattice calculations are seen to better reproduce the experimental ratios than the model calculations
Froggatt, C D
2005-01-01
It is proposed that dark matter could consist of compressed collections of atoms (or metallic matter) encapsulated into, for example, 20 cm big pieces of a different phase. The idea is based on the assumption that there exists at least one other phase of the vacuum degenerate with the usual one. Apart from the degeneracy of the phases we only assume Standard Model physics. The other phase has a Higgs VEV appreciably smaller than in the usual electroweak vacuum. The balls making up the dark matter are very difficult to observe directly, but inside dense stars may expand eating up the star and cause huge explosions (gamma ray bursts). The ratio of dark matter to ordinary baryonic matter is estimated to be of the order of the ratio of the binding energy per nucleon in helium to the difference between the binding energies per nucleon in heavy nuclei and in helium. Thus we predict approximately five times as much dark matter as ordinary baryonic matter!
Strange decays of nonstrange baryons
International Nuclear Information System (INIS)
The strong decays of excited nonstrange baryons into the final states ΛK, ΣK, and for the first time into Λ(1405)K, Λ(1520)K, Σ(1385)K, ΛK*, and ΣK*, are examined in a relativized quark pair creation model. The wave functions and parameters of the model are fixed by previous calculations of Nπ and Nππ, etc., decays. The results show that it should be possible to discover several new negative parity excited baryons and confirm the discovery of several others by analyzing these final states in kaon production experiments. They also establish clear predictions for the relative strengths of certain states to decay to Λ(1405)K and Λ(1520)K, which can be tested to determine if a three-quark model of the Λ(1405)K is valid. The authors results compare favorably with the results of partial wave analyses of the limited existing data for the ΛK and ΣK channels. They do not find large ΣK decay amplitudes for a substantial group of predicted and weakly established negative-parity states, in contrast to the only previous work to consider decays of these states into the strange final states ΛK and ΣK
Net-Baryon Physics: Basic Mechanisms
Alvarez-Muñiz, J; Dias de Deus, J; Santo, M C Espirito; Milhano, J G; Pimenta, M
2007-01-01
It is well known that, in nuclear collisions, a sizable fraction of the available energy is carried away by baryons. As the baryon number is conserved, the net-baryon $B-\\bar{B}$ retains information on the energy-momentum carried by the incoming nuclei. A simple but consistent model for net-baryon production in high energy hadron-hadron, hadron-nucleus and nucleus-nucleus collisions is presented. The basic ingredients of the model are valence string formation based on standard PDFs with QCD evolution and string fragmentation via the Schwinger mechanism. The results of the model are presented and compared with both data and existing models. These results show that a good description of the main features of net-baryon data is possible on the framework of a simplistic model, with the advantage of making the fundamental production mechanisms manifest.
Pion mean fields and heavy baryons
Yang, Ghil-Seok; Polyakov, Maxim V; Praszałowicz, Michał
2016-01-01
We show that the masses of the lowest-lying heavy baryons can be very well described in a pion mean-field approach. We consider a heavy baryon as a system consisting of the $N_c-1$ light quarks that induce the pion mean field, and a heavy quark as a static color source under the influence of this mean field. In this approach we derive a number of \\textit{model-independent} relations and calculate the heavy baryon masses using those of the lowest-lying light baryons as input. The results are in remarkable agreement with the experimental data. In addition, the mass of the $\\Omega_b^*$ baryon is predicted.
Baryon Mass in medium with Holographic QCD
Seo, Yunseok
2008-01-01
We study the baryon vertex (BV) in the presence of medium using DBI action and the force balance condition between BV and the probe branes. We note that a stable BV configuration exists only in some of the confining backgrounds. For the system of finite density, the issue is whether there is a canonical definition for the baryon mass in the medium. In this work, we define it as the energy of the deformed BV satisfying the force balance condition (FBC) with the probe brane. With FBC, lengths of the strings attached to the BV tend to be zero while the compact branes are enlongated to mimic the string. We attribute the deformation energy of the probe brane to the baryon-baryon interaction. We show that for a system with heavy quarks the baryon mass drops monotonically as a function of density while it has minimum in case of light quark system.
Measurements of the b baryon lifetime
Buskulic, D.; Casper, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Odier, P.; Pietrzyk, B.; Ariztizabal, F.; Chmeissani, M.; Crespo, J. M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, L.; Martinez, M.; Orteu, S.; Pacheco, A.; Padilla, C.; Palla, F.; Pascual, A.; Perlas, J. A.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Farilla, A.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Marinelli, N.; Natali, S.; Nuzzo, S.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Bonvicini, G.; Cassel, D.; Cattaneo, M.; Comas, P.; Coyle, P.; Drevermann, H.; Engelhardt, A.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Jacobsen, R.; Janot, P.; Jost, B.; Knobloch, J.; Lehraus, I.; Maggi, M.; Markou, C.; Martin, E. B.; Mato, P.; Meinhard, H.; Minten, A.; Miquel, R.; Oest, T.; Palazzi, P.; Pater, J. R.; Pusztaszeri, J.-F.; Ranjard, F.; Rensing, P.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Bardadin-Otwinowska, M.; Barres, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rossignol, J.-M.; Saadi, F.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Kyriakis, A.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Passalacqua, L.; Rougé, A.; Rumpf, M.; Tanaka, R.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Delfino, M.; Georgiopoulos, C.; 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.; Pepe-Altarelli, M.; Dorris, S. J.; Halley, A. W.; Ten Have, I.; Knowles, I. G.; Lynch, J. G.; Morton, W. T.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Thomson, F.; Thorn, S.; Turnbull, R. M.; Becker, U.; Braun, O.; Geweniger, C.; Graefe, G.; Hanke, P.; Hepp, V.; Kluge, E. E.; Putzer, A.; Rensch, B.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Colling, D. J.; Dornan, P. J.; Konstantinidis, N.; Moneta, L.; Moutoussi, A.; Nash, J.; San Martin, G.; Sedgbeer, J. K.; Stacey, A. M.; Dissertori, G.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Whelan, E. P.; Williams, M. I.; Galla, A.; Greene, A. M.; Kleinknecht, K.; Quast, G.; Raab, J.; Renk, B.; Sander, H.-G.; Wanke, R.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Thulasidas, M.; Nicod, D.; Payre, P.; Rousseau, D.; Talby, M.; Abt, I.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Jakobs, K.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Settles, R.; Seywerd, H.; Stierlin, U.; Denis, R. St.; Wolf, G.; Alemany, R.; Boucrot, J.; Callot, O.; Cordier, A.; Courault, F.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Musolino, G.; Nikolic, I.; Park, H. J.; Park, I. C.; Schune, M.-H.; Simion, S.; Veillet, J.-J.; Videau, I.; Abbaneo, D.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Gambino, D.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Rizzo, G.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Vannini, C.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Blair, G. A.; Bryant, L. M.; Cerutti, F.; Gao, Y.; Green, M. G.; Johnson, D. L.; Medcalf, T.; Mir, L. M.; Perrodo, P.; Strong, J. A.; Bertin, V.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Edwards, M.; Maley, P.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Trabelsi, A.; Vallage, B.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Beddall, A.; Booth, C. N.; Boswell, R.; Cartwright, S.; Combley, F.; Dawson, I.; Koksal, A.; Letho, M.; Newton, W. M.; Rankin, C.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Cowan, G.; Feigl, E.; Grupen, C.; Lutters, G.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Ragusa, F.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Bellantoni, L.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Harton, J. L.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I. J.; Sharma, V.; Turk, J. D.; Walsh, A. M.; Wu, Sau Lan; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.; Aleph Collaboration
1995-02-01
Using about 1.5 million hadronic Z decays recorded with the ALEPH detector, the lifetime of the b baryons has been measured using two independent data samples. From a maximum likelihood fit to the impact parameter distribution of leptons in 519 Λℓ - combinations containing a b baryon sample of 290 decays, the measured b baryon lifetime is τb-baryon = 1.05 -0.11+0.12(stat)±0.09(syst) ps. The lifetime of the Λb0 baryon from a maximum likelihood fit to the proper time distribution of 58 Λc+ℓ - candidates containing a Λb0 sample of 44 decays, is τΛb0 = 1.02 -0.18+0.23(stat) ± 0.06(syst) ps.
Dense detector for baryon decay
International Nuclear Information System (INIS)
Our studies indicate that the dense detector represents a potentially powerful means to search for baryon decay and to study this process, if it occurs. The detector has good angular resolution and particle identification properties for both showering and non-showering events. Its energy resolution is particularly good for muons, but pion, electron and photon energies can also be measured with resolutions of at least 25 percent (standard deviation). The dense detector has strong logistical advantages over other proposed schemes. These advantages imply not only a lower cost but also faster construction and higher reliability. A particular advantage is that the dense detector can be prototyped in order to optimize its characteristics prior to the construction of a large module. Subsequent modules can also be added easily, while the initial detector continues operation
Lifetime of Doubly Charmed Baryons
Institute of Scientific and Technical Information of China (English)
XU Xue-Fen; CHANG Chao-Hsi; LI Tong; LI Xue-Qian; WANG Yu-Ming
2008-01-01
In this work, we evaluate the lifetimes of the doubly charmed baryons cc+, cc++, and Ωcc+. We carefully calculate the non-spectator contributions at the quark level, where the Cabibbo-suppressed diagrams are also included. The hadronic matrix elements are evaluated in the simple non-relativistic harmonic oscillator model. Our numerical results are generally consistent with that obtained by other authors who used the diquark model. However, all the theoretical predictions on the lifetimes are one order larger than the upper limit set by the recent SELEX measurement. This discrepancy would be clarified by the future experiment. If more accurate experiment still confirms the value of the SELEX collaboration, there must be some unknown mechanism to be explored.
Diquark model of the baryon spectrum
International Nuclear Information System (INIS)
The presence of a coherent diquark structure within baryons has been suggested, both as a computational tool for simplifying some types of baryon calculations, and as an explanation for scaling violations in deep inelastic scattering. In this paper we consider the implications of the diquark hypothesis for baryons spectroscopy. Treating the diquark as an s-wave bound state of two quarks reduces the problem of three-body quark excitations within baryons to that of a two-body quark-diquark interaction. The spin-dependent excitation levels of the quark-diquark system can then be calculated in perturbative QCD, using a non-relativistic one-gluon-exchange approximation. The spectrum generated by this model differs from the conventional symmetric quark model spectrum in several crucial respects. Firstly, spin-orbit mass splitting between baryons is easily accommodated in the diquark picture, unlike the conventional model, where it must be cancelled ad hoc in order to obtain a reasonable fit to the mass spectrum. Secondly, the QCD parameters needed to fit the baryon spectrum in the diquark model are essentially the same as those used in the meson spectrum. This allows us to give a unified description of spin-dependent forces in mesons and baryons, which has not been possible in the symmetric quark model. We conclude with a qualitative discussion of spin-independent (multiple gluon exchange) forces in the diquark model, using effective confining potentials of the form, V(r) approx. r/sup n/. 28 references
Holographic heavy ion collisions with baryon charge
Casalderrey-Solana, Jorge; van der Schee, Wilke; Triana, Miquel
2016-01-01
We numerically simulate collisions of charged shockwaves in Einstein-Maxwell theory in anti-de Sitter space as a toy model of heavy ion collisions with non-zero baryon charge. The stress tensor and the baryon current become well described by charged hydrodynamics at roughly the same time. The effect of the charge density on generic observables is typically no larger than 15\\%. %The rapidity profile of the charge is wider than the profile of the local energy density. We find significant stopping of the baryon charge and compare our results with those in heavy ion collision experiments.
Holographic monopole catalysis of baryon decay
International Nuclear Information System (INIS)
We study how monopole catalysis of baryon decay is realized in holographic QCD. Physics of monopole catalysis becomes much simpler in holographic description as it occurs due to the violation of the Bianchi identity for the 5D gauge symmetry when magnetic monopole is present. In holographic QCD we find a unified picture of the baryon number violation under magnetic monopole or electroweak sphaleron, giving a new mechanism of baryon number violation. We also embed our set-up in the string theory model by Sakai and Sugimoto. (author)
Baryon octet interactions in the Skyrme model
International Nuclear Information System (INIS)
We calculate baryon-baryon interactions in the SU(3) octet using the Skyrme model. We employ an exact diagonalization procedure for the symmetry-breaking term in the solution of the single-baryon B=1 problem, and a product ansatz for the B=2 solutions. Qualitatively, the results resemble those obtained for the NN potentials using the product ansatz with no additional dynamical features. In particular, the central potentials for the ΛN and ΣN systems do not exhibit attraction. (orig.)
Chiral Dynamics of Baryons from String Theory
Hong, D K; Yee, H U; Yi, P; Hong, Deog Ki; Rho, Mannque; Yee, Ho-Ung; Yi, Piljin
2007-01-01
We study baryons in an AdS/CFT model of QCD by Sakai and Sugimoto, realized as small instantons with fundamental string hairs. We introduce an effective field theory of the baryons in the five-dimensional setting, and show that the instanton interpretation implies a particular magnetic coupling. Dimensional reduction to four dimensions reproduces the usual chiral effective action, and in particular we estimate the axial coupling $g_A$ between baryons and pions and the magnetic dipole moments, both of which are proportional to $N_c$. We extrapolate to finite $N_c$ and discuss subleading corrections.
Calculation of baryon sum rules and SU(4) mass formulae for mesons and baryons
International Nuclear Information System (INIS)
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)
A Program for Baryon Generation and Its Applications to Baryon Fragmentation in DIS
Eden, Patrik
1996-01-01
In an earlier paper, we discuss the ``popcorn'' model for baryon production in quark and gluon jets, and present an improved model (which we call Modified Popcorn Scenarium, MOPS). In this paper we give a manual to the MC program based on MOPS, and also discuss the application of the model to baryon fragmentation, i.e. fragmentation of strings originally contaning a diquark. Model predictions for baryon production in DIS are compared with data.
Neutron-antineutron Oscillation and Baryonic Majoron: Low Scale Spontaneous Baryon Violation
Berezhiani, Zurab
2015-01-01
We discuss a possibility that baryon number $B$ is spontaneously broken at low scales, of the order of MeV or even smaller, so that the neutron-antineutron oscillation can be induced 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 $B-L$ symmetry, baryo-majoron can be identified with the ordinary majoron associated with t...
Suppression of Baryon Diffusion and Transport in a Baryon Rich Strongly Coupled Quark-Gluon Plasma.
Rougemont, Romulo; Noronha, Jorge; Noronha-Hostler, Jacquelyn
2015-11-13
Five dimensional black hole solutions that describe the QCD crossover transition seen in (2+1)-flavor lattice QCD calculations at zero and nonzero baryon densities are used to obtain predictions for the baryon susceptibility, baryon conductivity, baryon diffusion constant, and thermal conductivity of the strongly coupled quark-gluon plasma in the range of temperatures 130 MeV≤T≤300 MeV and baryon chemical potentials 0≤μ(B)≤400 MeV. Diffusive transport is predicted to be suppressed in this region of the QCD phase diagram, which is consistent with the existence of a critical end point at larger baryon densities. We also calculate the fourth-order baryon susceptibility at zero baryon chemical potential and find quantitative agreement with recent lattice results. The baryon transport coefficients computed in this Letter can be readily implemented in state-of-the-art hydrodynamic codes used to investigate the dense QGP currently produced at RHIC's low energy beam scan. PMID:26613433
Net-Baryon Physics: Basic Mechanisms
International Nuclear Information System (INIS)
How does the fraction of energy carried by the net-baryon, B - anti-B , evolve as a function of the centre-of-mass collisional energy per nucleon, sqrt(s)? In order to answer this question we explore the net-baryon mechanism and it is propose a simple but consistent model for net-baryon production in high energy hadron-hadron, hadron-nucleus and nucleus-nucleus collisions. The model basic ingredients are: valence string formation based on standard PDFs with QCD evolution; and string fragmentation via the Schwinger mechanism. Our model shows that a good description of the main features of net-baryon data is possible in the framework of a simplistic model, with the advantage of making the fundamental production mechanisms manifest. We compare results both with data and existing models. (authors)
A holographic model for the baryon octet
Fang, Zhen
2016-01-01
By adopting the nonlinear realization of chiral symmetry, a holographic model for the baryon octet is proposed. The mass spectra of the baryon octet and their low-lying excited states are calculated, which show good consistency with experiments. The couplings of pion to nucleons are derived in two gauges and are shown to be equivalent with each other. It also shows that only derivative couplings of pion to nucleons appear in this holographic model. The coupling constant is then calculated.
Meson and baryon spectroscopy on the lattice
Energy Technology Data Exchange (ETDEWEB)
David Richards
2010-12-01
Recent progress at understanding the excited state spectrum of mesons and baryons is described. I begin by outlining the application of the variational method to compute the spectrum, and the program of anisotropic clover lattice generation designed for hadron spectroscopy. I present results for the excited meson spectrum, with continuum quantum numbers of the states clearly delineated. I conclude with recent results for the low lying baryon spectrum, and the prospects for future calculations.
Static-static-light baryonic potentials
Najjar, Johannes; Bali, Gunnar
2009-01-01
We determine doubly heavy baryonic potentials as a function of the distance between the two static sources, coupled to a light relativistic quark, for different quantum numbers. We use the variational method to compute the ground state and the first two excitations. These can be used as an input to nonrelativistic models or to NRQCD calculations of properties of doubly heavy baryons. We compare our findings with a factorization model. We employ all-to-all propagator methods, improved by an ad...
Anomaly-induced charges in baryons
Eto, Minoru; Hashimoto, Koji; Iida, Hideaki; Ishii, Takaaki; Maezawa, Yu
2011-01-01
We show that quantum chiral anomaly of QCD in magnetic backgrounds induces a novel structure of electric charge inside baryons. To illustrate the anomaly effect, we employ the Skyrme model for baryons, with the anomaly-induced gauged Wess-Zumino term (\\pi_0 + (multi-pion)) E_i B_i. Due to this term, the Skyrmions giving a local pion condensation ((\\pi_0 + (multi-pion)) \
Baryon Oscillations in the Large Scale Structure
Cooray, Asantha
2001-01-01
We study the possibility for an observational detection of oscillations due to baryons in the matter power spectrum and suggest a new cosmological test using the angular power spectrum of halos. The "standard rulers" of the proposed test involve overall shape of the matter power spectrum and baryon oscillation peaks in projection, as a function of redshift. Since oscillations are erased at non-linear scales, traces at redshifts greater than 1 are generally preferred. Given the decrease in num...
String junction as a baryonic constituent
Kalashnikova, Yu S
1995-01-01
We extend the model for QCD string with quarks to consider the Mercedes Benz string configuration describing the three-quark baryon. Under the assumption of adiabatic separation of quark and string junction motion we formulate and solve the classical equation of motion for the junction.We dare to quantize the motion of the junction, and discuss the impact of these modes on the baryon spectra.
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.
Baryonic matter perturbations in decaying vacuum cosmology
Energy Technology Data Exchange (ETDEWEB)
Marttens, R.F. vom; Zimdahl, W. [Departamento de Física, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitória, Espírito Santo (Brazil); Hipólito-Ricaldi, W.S., E-mail: rodrigovonmarttens@gmail.com, E-mail: wiliam.ricaldi@ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br [Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, CEUNES, Rodovia BR 101 Norte, km. 60, CEP 29932-540, São Mateus, Espírito Santo (Brazil)
2014-08-01
We consider the perturbation dynamics for the cosmic baryon fluid and determine the corresponding power spectrum for a Λ(t)CDM model in which a cosmological term decays into dark matter linearly with the Hubble rate. The model is tested by a joint analysis of data from supernovae of type Ia (SNIa) (Constitution and Union 2.1), baryonic acoustic oscillations (BAO), the position of the first peak of the anisotropy spectrum of the cosmic microwave background (CMB) and large-scale-structure (LSS) data (SDSS DR7). While the homogeneous and isotropic background dynamics is only marginally influenced by the baryons, there are modifications on the perturbative level if a separately conserved baryon fluid is included. Considering the present baryon fraction as a free parameter, we reproduce the observed abundance of the order of 5% independently of the dark-matter abundance which is of the order of 32% for this model. Generally, the concordance between background and perturbation dynamics is improved if baryons are explicitly taken into account.
Study of the baryon-baryon interaction in nucleon-nucleon and pion-deuteron scattering
International Nuclear Information System (INIS)
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
Papastergis, Emmanouil; 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 calculated using atomic hydrogen (HI) emission line data from the Arecibo Legacy Fast ALFA (ALFALFA) survey. By using the technique of abundance matching, we combine the measured baryonic function (BMF) of galaxies with the dark matter halo mass function in a LCDM universe, in order to determine the galactic baryon fraction as a function of host halo mass. We find that the baryon fraction of low-mass halos is much smaller than the cosmic value, even when atomic gas is taken into account. We find that the galactic baryon deficit increases monotonically with decreasing halo mass, in contrast with previous studies which suggested an approximately constant baryon fraction at the low-mass end. We argue that the observed baryon...
Compressed Baryonic Matter: from Nuclei to Pulsars
Xu, Renxin
2013-01-01
Our world is wonderful because of the negligible baryonic part although unknown dark matter and dark energy dominate the Universe. Those nuclei in the daily life are forbidden to fuse by compression due to the Coulomb repulse, nevertheless, it is usually unexpected in extraterrestrial extreme-environments: the gravity in a core of massive evolved star is so strong that all the other forces (including the Coulomb one) could be neglected. Compressed baryonic matter is then produced after supernova, manifesting itself as pulsar-like stars observed. The study of this compressed baryonic matter can not only be meaningful in fundamental physics (e.g., the elementary color interaction at low-energy scale, testing gravity theories, detecting nano-Hertz background gravitational waves), but has also profound implications in engineering applications (including time standard and navigation), and additionally, is focused by Chinese advanced telescopes, either terrestrial or in space. Historically, in 1930s, L. Landau spec...
Spectroscopy of charmed baryons from lattice QCD
Padmanath, M; Mathur, Nilmani; Peardon, Michael
2014-01-01
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. 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) $\\otimes$ 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.
Spectroscopy of charmed baryons from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Padmanath, M. [Univ. of Graz (Austria). Inst. of Physics; Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Mathur, Nilmani [Tata Institute of Fundamental Research, Bombay (India); Peardon, Michael [Trinity College, Dublin (Ireland)
2015-01-01
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. 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) x 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.
Dark Matter and the Baryon Asymmetry
Farrar, G R; Farrar, Glennys R.; Zaharijas, Gabrijela
2006-01-01
We present a mechanism to generate the baryon asymmetry of the Universe which preserves the net baryon number created in the Big Bang. If dark matter particles carry baryon number $B_X$, and $\\sigma^{\\rm annih}_{\\bar{X}} < \\sigma^{\\rm annih}_{X} $, the $\\bar{X}$'s freeze out at a higher temperature and have a larger relic density than $X$'s. If $m_X \\lsi 4.5 B_X $GeV and the annihilation cross sections differ by $\\mathcal{O}$(10%) or more, this type of scenario naturally explains the observed $\\Omega_{DM} \\approx 5 \\Omega_b$. Two concrete examples are given, one of which can be excluded on observational grounds.
International Nuclear Information System (INIS)
Ellis, Gabathuler and Karliner [Phys. Lett. B 217 (1989) 173] have recently proposed on theoretical grounds that the Okubo-Zweig-Iizuka (OZI) rule does not apply to baryonic vertices because baryons contain a significant number of strange quark-antiquark pairs, and they claim some phenomological support for this proposal. In the light of this, the excellent data on backward meson production is critically re-examined. We find some evidence for OZI-evading couplings for the case of the φ, and put bounds on any OZI-violating couplings of the f2' (1525). The violations found do not follow the pattern predicted by Ellis et al. and are also so small as to make their significance questionable. We also re-examine the data on the related question of Z* (exotic baryon) exchange. (orig.)
Dark Matter Assimilation into the Baryon Asymmetry
D'Eramo, Francesco; Thaler, Jesse
2011-01-01
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 "assimilation", 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.
Spectroscopy of charmed baryons from lattice QCD
International Nuclear Information System (INIS)
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. 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) x 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.
Baryon production from embedded metastable strings
Karouby, Johanna
2013-01-01
We quantify the baryon anti-baryon production generated by a metastable cosmic string, similar to the embedded pion string. More precisely, we study skyrmion production mediated by instantons generated by a pion-like metastable string in contact with a thermal bath, and interpret these Skyrmions as baryons. As shown in a previous work, the core of such a metastable string can melt due to quantum tunneling in the charged field direction. The specific configuration of our string containing 4 scalar fields out of equilibrium in contact with a thermal bath is shown to yield skyrmion production with partial or integer winding number. In this work, we describe and quantify this skyrmion production per unit length of the string. We also evaluate the skyrmion-anti skyrmions production by a dense string network by invoking similarity with the Skyrmion production in a phase transition.
Physical properties of the chiral quantum baryon
International Nuclear Information System (INIS)
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)
Strange anti-baryons---QGP versus HC
International Nuclear Information System (INIS)
We study quark-gluon plasma (QGP) and hadronic gas (HG) models of the central fireball presumed to be the source of abundantly produced strange (anti-)baryons in S→W collisions at 200 GeV A. We consider how multi-strange (anti-)baryon multiplicities depend on strangeness conservation and compare the HG and QGP fireball scenarios. We argue that the total particle multiplicity emerging from the central rapidity region as well as the variation of production rates with changes in the beam energy allows to distinguish between the two reaction scenarios
Heavy baryons in the large Nc limit
Albertus, C; Fernando, I P; Goity, J L
2015-01-01
It is shown that in the large Nc limit heavy baryon masses can be estimated quantitatively in a 1/Nc expansion using the Hartree approximation. The results are compared with available lattice calculations for different values of the ratio between the square root of the string tension and the heavy quark mass tension independent of Nc. Using a potential adjusted to agree with the one obtained in lattice QCD, a variational analysis of the ground state spin averaged baryon mass is performed using Gaussian Hartree wave functions. Relativistic corrections through the quark kinetic energy are included. The results provide good estimates for the first sub-leading in 1/Nc corrections.
Properties of doubly and triply heavy baryons
International Nuclear Information System (INIS)
We calculate the mass and residue of the doubly/triply heavy spin-1/2 and spin- 3/2 baryons containing two/three heavy b or c quarks in the framework of QCD sum rules. We use the most general interpolating currents in symmetric and anti-symmetric forms with respect to the exchange of heavy quarks, to calculate the two-point correlation functions describing the baryons under consideration. A comparison of the obtained results with the existing experimental data as well as predictions of other theoretical approaches is also made
Infrared enhancement in single-baryon systems
Lv, Songlin
2016-01-01
The pion-baryon triangle diagram is inspected for the special kinematic region in which the squared momentum transfer is close to $4m_\\pi^2$. The pion propagators can have very small energies, as opposed to $\\sim m_\\pi$ in the physical region, which allows the nucleon propagator to be near its mass shell. This observation leads us to conclude that in this particular domain the triangle diagram is augmented by $\\mathcal{O}(m_N/m_\\pi)$ compared with the standard counting of chiral perturbation theory, hence an infrared enhancement in the single-baryon sector.
A measurement of the b baryon lifetime
Buskulic, D.; Decamp, D.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Mours, B.; Alemany, R.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Delfino, M.; Fernandez, E.; Gaitan, V.; Garrido, Ll.; Pacheco, A.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Maggi, M.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Lou, J.; Qiao, C.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhao, W.; Atwood, W. B.; Bauerdick, L. A. T.; Blucher, E.; Bonvicini, G.; Bossi, F.; Boudreau, J.; Burnett, T. H.; Drevermann, H.; Forty, R. W.; Hagelberg, R.; Harvey, J.; Haywood, S.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lançon, E.; Lehraus, I.; Lohse, T.; Lusiani, A.; Martinez, M.; Mato, P.; Mattison, T.; Meinhard, H.; Menary, S.; Meyer, T.; Minten, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Perlas, J. A.; Pusztaszeri, J.-F.; Ranjard, F.; Redlinger, G.; Rolandi, L.; Roth, A.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Wachsmuth, H.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Badaud, F.; Bardadin-Otwinowska, M.; Bencheikh, A. M.; El Fellous, R.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Pietrzyk, B.; Proriol, J.; Prulhière, F.; Stimpfl, G.; Fearnley, T.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Efthymiopoulos, I.; Kyriakis, A.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Fouque, G.; Orteu, S.; Rosowsky, A.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Moneta, L.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Lannutti, J.; Levinthal, D.; Mermikides, M.; Sawyer, L.; Wasserbaech, S.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Picchi, P.; Altoon, B.; Boyle, O.; Colrain, P.; Ten Have, I.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Scarr, J. M.; Smith, K.; Thompson, A. S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geiges, R.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Belk, A. T.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Dugeay, S.; Greene, A. M.; Hassard, J. F.; Lieske, N. M.; Nash, J.; Patton, S. J.; Payne, D. G.; Phillips, M. J.; Sedgbeer, J. K.; Tomalin, I. R.; Wright, A. G.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Steeg, F.; Walther, S. M.; Wolf, B.; Aubert, J.-J.; Benchouk, C.; Bernard, V.; Bonissent, A.; Carr, J.; Coyle, P.; Drinkard, J.; Etienne, F.; Papalexiou, S.; Payre, P.; Qian, Z.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Bauer, C.; Blum, W.; Brown, D.; Cowan, G.; Dehning, B.; Dietl, H.; Dydak, F.; Fernandez-Bosman, M.; Frank, M.; Halley, A. W.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Rotscheidt, H.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, U.; Stiegler, U.; Denis, R. St.; Takashima, M.; Thomas, J.; Wolf, G.; Bertin, V.; Boucrot, J.; Callot, O.; Chen, X.; Cordier, A.; Davier, M.; Grivaz, J.-F.; Heusse, Ph.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Zhang, Z.; Zomer, F.; Abbaneo, D.; Amendolia, S. R.; Bagliesi, G.; Batignani, G.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Carpinelli, M.; Ciocci, M. A.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Focardi, E.; Forti, F.; Giassi, A.; Giorgi, M. A.; Ligabue, F.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Carter, J. M.; Green, M. G.; March, P. V.; Mir, Ll. M.; Medcalf, T.; Quazi, I. S.; Strong, J. A.; West, L. R.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Edwards, M.; Fisher, S. M.; Jones, T. J.; Norton, P. R.; Salmon, D. P.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Kozanecki, W.; Lemaire, M. C.; Locci, E.; Loucatos, S.; Monnier, E.; Perez, P.; Perrier, F.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Ashman, J. G.; Babbage, W.; Booth, C. N.; Buttar, C.; Carney, R. E.; Cartwright, S.; Combley, F.; Hatfield, F.; Reeves, P.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Grupen, C.; Mirabito, L.; Rivera, F.; Schäfer, U.; Ganis, G.; Giannini, G.; Gobbo, B.; Ragusa, F.; Bellantoni, L.; Chen, W.; Cinabro, D.; Conway, J. S.; Cowen, D. F.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Jared, R. C.; Leclaire, B. W.; Lishka, C.; Pan, Y. B.; Pater, J. R.; Saadi, Y.; Sharma, V.; Schmitt, M.; Shi, Z. H.; Walsh, A. M.; Weber, F. V.; Whitney, M. H.; Wu, Sau Lan; Wu, X.; Zobernig, G.; Aleph Collaboration
1992-12-01
In 451 000 hadronic Z 0 decays, recorded with the ALEPH detector at LEP, the yields of Λℓ - and Λℓ + combinations are measured. Semileptonic decays of b baryons result in a signal of 122± 18 (stat.) -23+22 (syst.) Λℓ - combinations. From a fit to the impact parameter distributions of the leptons in the Λℓ - sample, the lifetime of b baryons is measured to be 1.12 -0.29+0.32 (stat.) ±0.16 (syst.) ps.
Heavy flavor baryons in hypercentral model
Indian Academy of Sciences (India)
Bhavin Patel; Ajay Kumar Rai; P C Vinodkumar
2008-05-01
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 . The ground state masses of the heavy flavor, $J^{P} = \\dfrac{1}{2}^{+}$ and $\\dfrac{3}{2}^{+}$ baryons are computed for different power indices, 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 = 1.0.
Beautiful and other heavy baryons revisited
Energy Technology Data Exchange (ETDEWEB)
Martin, A.; Richard, J.M.
1987-02-19
We discuss the mass range for the beautiful baryons ..lambda../sub b/, ..sigma../sub b/ and ..sigma../sub b//sup */ allowed by rigorous inequalities which are derived in the framework of potential models but have probably a broader domain of validity. We obtain at the same time lower bounds on the masses of other baryons. We also compare the numerical prediction of several explicit models. There are convergent indications towards a mass of about 5.6 GeV for the ..lambda../sub b/.
Two-baryon forces from skyrmions
International Nuclear Information System (INIS)
Background material on solitons and, especially, skyrmions is provided and the applications of the latter to the derivation of the nucleon-nucleon force is reviewed with attention to the product Ansatz, additional terms in the Lagrangian, baryon resonance admixtures, dilatons, and exact two-or three-dimensional solutions for the B=2 system in order to find the sources of attraction in the central and spin-orbit potentials. We discuss extensions to two-baryon systems with nonzero strangeness and address applications to the behavior of the nucleon in nuclei achieved from skyrmions. (author)
Dynamically generated hidden-charm baryon resonances
Lutz, M F M
2006-01-01
Identifying a zero-range exchange of vector mesons as the driving force for the s-wave scattering of pseudo-scalar mesons off the baryon ground states, a rich spectrum of hadronic nuclei is formed. We argue that chiral symmetry and large-$N_c$ considerations determine that part of the interaction which generates the spectrum. We suggest the existence of strongly bound crypto-exotic baryons, which contain a charm-anti-charm pair. Such states are narrow since they can decay only via OZI-violating processes.
Octet baryon masses and sigma terms in covariant baryon chiral perturbation theory
Ren, Xiu-Lei; Geng, Li-Sheng; Meng, Jie
2015-01-01
We report on a recent study of the ground-state octet baryon masses and sigma terms in covariant baryon chiral perturbation theory with the extended-on-mass-shell scheme up to next-to-next-to-next-to-leading order. To take into account lattice QCD artifacts, the finite-volume corrections and finite lattice spacing discretization effects are carefully examined. We performed a simultaneous fit of all the $n_f = 2+1$ lattice octet baryon masses and found that the various lattice simulations are ...
Measurement of inclusive baryon production in B meson decays
International Nuclear Information System (INIS)
Using the ARGUS detector at the e+e- storage ring DORIS II at DESY, we have studied B meson decays into baryons p and Λ. From the simultaneous analysis of p and Λ yields, panti p and Λanti p correlations, and various lepton-baryon and lepton-baryon-antibaryon correlations the inclusive branching ratio is found to be BR (B→baryons)=(6.8±0.5±0.3)%. (orig.)
Baryon superfluidity and neutrino emissivity of neutron stars
Takatsuka, T.; Tamagaki, R.
2004-01-01
For neutron stars with hyperon-mixed core, neutrino emissivity is studied under the equation of state, obtained by introducing repulsive three-body force universal for all baryons so as to assure the maximum mass compatible with the observation. By paying attention to the density-dependence of critical temperatures of baryon superfluids, which reflect the nature of baryon-baryon interaction and control neutron star cooling, we show what neutrino emission processes are efficient in the regions...
Octet baryon magnetic moments in light cone QCD sum rules
Aliev, T M; Özpineci, A
2002-01-01
Octet baryon magnetic moments are calculated in framework of the light cone QCD sum rules. The analysis is carried for the general form of the interpolating currents for octet baryons. A comparison of our results on the magnetic moments of octet baryons with the predictions of other approaches and experimental data is presented.
Semileptonic heavy-to-light decays of baryons
International Nuclear Information System (INIS)
The results about semileptonic decays of baryons with only heavy quark into light baryons are reported. These processes are considered in the framework of the quark confinement model. Weak form factors, decay rates and differential distributions of semileptonic heavy-to-light baryon decays are calculated. The limit mQ→∞ is examined. 23 refs.; 14 figs.; 1 tab
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
Neutron-antineutron Oscillation and Baryonic Majoron: Low Scale Spontaneous Baryon Violation
Berezhiani, Zurab
2015-01-01
We discuss a possibility that baryon number $B$ is spontaneously broken at low scales, of the order of MeV or even smaller, so that the neutron-antineutron oscillation can be induced 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 $B-L$ symmetry, baryo-majoron can be identified with the ordinary majoron associated with the spontaneous breaking of lepton number, with interesting implications for neutrinoless $2\\beta$ becay with the majoron emission, etc. We also discuss a hypothesis suggesting that baryon number maybe spontaneously broken by the QCD itself via the six-quark condensates.
Twisted baryon loop effects in DTU
International Nuclear Information System (INIS)
Within the framwork of DTU we propose a simple model for mesons, baryons and baryonium which allows use to calculate the effects of inserting non-planar antiBB loops in all possible ways into meson and baryonium propagators. We study the renormalization of the leading non-zero isospin trajectories and the mixing of qantiq and qqantiqantiq states
Baryon number violation and particle collider experiments
International Nuclear Information System (INIS)
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
Beauty baryon decays: a theoretical overview
International Nuclear Information System (INIS)
I overview the theoretical status and recent progress on the calculations of beauty baryon decays focusing on the QCD aspects of the exclusive semi-leptonic Λb → pℓμ decay at large recoil and theoretical challenges of radiative and electro-weak penguin decays Λb → Λγ,Λℓ+ℓ−
Heavy-baryon weak form factors
International Nuclear Information System (INIS)
It has recently been shown that hadrons containing a single heavy quark exhibit a new flavor-spin symmetry of QCD. We exploit this symmetry to obtain model-independent absolutely normalized predictions for some heavy-baryon weak form factors at zero recoil as well as relations between such form factos at nonzero recoil. (orig.)
On gauged Baryon and Lepton numbers
International Nuclear Information System (INIS)
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
Charmed baryons in bootstrap quark model
Gerasyuta, S. M.; Ivanov, D.V.
2001-01-01
In the framework of dispersion relation technique the relativistic three-quark equations including heavy quarks are found. The approximate solutions of the relativistic three-particles equations based on the extraction of leading singularities of amplitudes are obtained. The mass values of S-wave multiplets of charmed baryons are calculated.
The baryonic self similarity of dark matter
Energy Technology Data Exchange (ETDEWEB)
Alard, C., E-mail: alard@iap.fr [Institut d' Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris (France)
2014-06-20
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 {sup 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.
Baryons in the unquenched quark model
Bijker, R; Lopez-Ruiz, M A; Santopinto, E
2016-01-01
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 $^{3}P_{0}$ quark-antiquark pair-creation mechanism. Particular attention is paid to the spin and flavor content of the proton, magnetic moments and $\\beta$ decays of octet baryons.
Excited mass spectra of Σ+c baryon
International Nuclear Information System (INIS)
Baryons are strongly interacting fermions made up of three quarks. Recently, many of single charm baryons are discovered by different colliders like CLEO, Belle, BABAR, etc. Among different phenomenological Quark models, we practise on Hypercentral Constituent Quark Model (hCQM) with coulomb plus power potential. The methodology of single charmed Baryon Σ+c is derived in the paper. Our predictions for charmed baryon masses are matched with other theoretical prediction as well as known experimental data. The obtained results are used for constructing the heavy baryon Regge trajectories in the (nr, M2)
Heavy baryons in the large Nc limit
Albertus, C.; Ruiz Arriola, E.; Fernando, I. P.; Goity, J. L.
2015-11-01
It is shown that in the large Nc limit heavy baryon masses can be estimated quantitatively in a 1 /Nc expansion using the Hartree approximation. The results are compared with available lattice calculations for different values of the ratio between the square root of the string tension and the heavy quark mass √{ σ} /mQ. These estimates implement important 1 /Nc corrections and assume a string tension independent of Nc. Using a potential adjusted to agree with the one obtained in lattice QCD, a variational analysis of the ground state spin averaged baryon mass is performed using Gaussian Hartree wave functions. Relativistic corrections through the quark kinetic energy are included. The results provide good estimates for the first sub-leading in 1 /Nc corrections.
The Compressed Baryonic Matter experiment at FAIR
Energy Technology Data Exchange (ETDEWEB)
Senger, P. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)
2011-07-15
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 high densities, and the search for the deconfinement and chiral phase transitions. The CBM detector is designed to measure both bulk observables with large acceptance and rare diagnostic probes such as charmed particles and vector mesons decaying into lepton pairs. The layout and the physics performance of the proposed CBM experimental facility will be discussed.
Large-distance properties of holographic baryons
International Nuclear Information System (INIS)
Employing the asymptotic instanton solution in an arbitrary background of a set of holographic QCD models, we show that baryon form factors have a precise large-distance behavior regardless of the background. The dependence coincides with that obtained from general chiral soliton models and large-NC chiral perturbation theory. The nonlinear terms in the equations of motion are necessary to recover the correct results. We also show that the holographic currents have the right structure at low energy if the solutions of the full equation of motion, instead of the linearized ones, are used. The indication is that in this holographic approach, the linearized approximation used in the meson sector is not appropriate for the solitonic description of the baryons
Two Baryons with Twisted Boundary Conditions
Energy Technology Data Exchange (ETDEWEB)
Briceno, Raul [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Davoudi, Zohreh [Univ. of Washington, Seattle, WA (United States) and Institute for Nuclear Theory, Seattle, WA (United States); Luu, Thomas [Lawrence Livermore National Laboratory, Livermore, CA (United States); Savage, Martin [Univ. of Washington, Seattle, WA (United States) and Institute for Nuclear Theory, Seattle, WA (United States)
2014-04-01
The quantization condition for two particle systems with arbitrary number of two-body open coupled-channels, spin and masses in a finite cubic volume is presented. The condition presented is in agreement with all previous studies of two-body systems in a finite volume. The result is fully relativistic and holds for all momenta below inelastic thresholds and is exact up to exponential volume corrections that are governed by m{sub {pi}} L, where m{sub {pi}} is the pion mass and L is the spatial extent of my box. Its implication for the studies of coupled-channel baryon-baryon systems is discussed, and the necessary tools for implementing the formalism are review.
Baryon Dynamics, Dark Matter Substructure, and Galaxies
Weinberg, D H; Davé, R; Katz, N; Colombi, Stephane; Dav\\'e, Romeel; Katz, Neal; Weinberg, David H.
2006-01-01
By comparing a collisionless cosmological N-body simulation (DM) to an SPH simulation with the same initial conditions, we investigate the correspondence between the dark matter subhalos produced by collisionless dynamics and the galaxies produced by dissipative gas dynamics in a dark matter background. When galaxies in the SPH simulation become satellites in larger groups, they retain local dark matter concentrations (SPH subhalos) whose mass is typically five times their baryonic mass. The more massive subhalos of the SPH simulation have corresponding subhalos of similar mass and position in the DM simulation; at lower masses, there is fairly good correspondence, but some DM subhalos are in different spatial positions and some suffer tidal stripping or disruption. The halo occupation statistics of DM subhalos -- the mean number of subhalos, pairs, and triples as a function of host halo mass -- are very similar to those of SPH subhalos and SPH galaxies. Gravity of the dissipative baryon component amplifies t...
Strong decays of nonstrange q3 baryons
International Nuclear Information System (INIS)
We study strong decays of nonstrange baryons by making use of the algebraic approach to hadron structure. Within this framework we derive closed expressions for decay widths in an elementary-meson emission model and use these to analyze the experimental data for N*→N+π, N*→Δ+π, N*→N+η, Δ*→N+π, Δ*→Δ+π, and Δ*→Δ+η decays. copyright 1997 The American Physical Society
Heavy baryon spectroscopy with relativistic kinematics
International Nuclear Information System (INIS)
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.
Baryon production in e+e- annihilation
International Nuclear Information System (INIS)
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)
Determining properties of baryon resonances in nuclei
International Nuclear Information System (INIS)
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 Δ33(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
Primordial Deuterium Abundance and Cosmic Baryon Density
Hogan, Craig J.
1994-01-01
The comparison of cosmic abundances of the light elements with the density of baryonic stars and gas in the universe today provides a critical test of big bang theory and a powerful probe of the nature of dark matter. A new technique allows determination of cosmic deuterium abundances in quasar absorption clouds at large redshift, allowing a new test of big bang homogeneity in diverse, very distant systems. The first results of these studies are summarized, along with their implications. The ...
Quark Orbital Angular Momentum in the Baryon
Song, Xiaotong
2000-01-01
Analytical and numerical results, for the orbital and spin content carried by different quark flavors in the baryons, are given in the chiral quark model with symmetry breaking. The reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital motion of quarks and antiquarks. The orbital angular momentum for each quark flavor in the proton as a function of the partition factor $\\kappa$ and the chiral splitting probability $a$ is shown...
Baryon Ratios in Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
MAZhong-Biao; MIAOHong; GAOChong-Shou
2003-01-01
A way to calculate ratios of baryon produced from quark gluon plasma in relativistic heavy ion collisions is presented. It is assumed that at the beginning of the hadronlzation there are diquarks and anti-diquarks in the quark matter. The number of three-quark states is distributed between the corresponding multiplets, and hadronic decays are taken into account. The results are shown at last.
Understanding the baryon and meson spectra
Energy Technology Data Exchange (ETDEWEB)
Pennington, Michael R. [JLAB
2013-10-01
A brief overview is given of what we know of the baryon and meson spectra, with a focus on what are the key internal degrees of freedom and how these relate to strong coupling QCD. The challenges, experimental, theoretical and phenomenological, for the future are outlined, with particular reference to a program at Jefferson Lab to extract hadronic states in which glue unambiguously contributes to their quantum numbers.
Baryon form factors: Model-independent results
International Nuclear Information System (INIS)
Baryon form factors can be analyzed in a largely model-independent fashion in terms of two complementary approaches. These are chiral perturbation theory and dispersion relations. I review the status of dispersive calculations of the nucleon electromagnetic form factors in the light of new data. Then, I present the leading one-loop chiral perturbation theory analysis of the hyperon and the strange nucleon form factors. Open problems and challenges are also discussed
Universal fitting formulae for baryon oscillation surveys
Blake, Chris; Parkinson, David; Glazebrook, Karl; Bassett, Bruce A.; Kunz, Martin; Nichol, Robert C.
2006-01-01
The next generation of galaxy surveys will attempt to measure the baryon oscillations in the clustering power spectrum with high accuracy. These oscillations encode a preferred scale which may be used as a standard ruler to constrain cosmological parameters and dark energy models. In this paper we present simple analytical fitting formulae for the accuracy with which the preferred scale may be determined in the tangential and radial directions by future spectroscopic and photometric galaxy re...
Optimal Redshift Weighting For Baryon Acoustic Oscillations
Zhu, Fangzhou; Padmanabhan, Nikhil; White, Martin
2014-01-01
Future baryon acoustic oscillation (BAO) surveys will survey very large volumes, covering wide ranges in redshift. We derive a set of redshift weights to compress the information in the redshift direction to a small number of modes. We suggest that such a compression preserves almost all of the signal for most cosmologies, while giving high signal-to-noise measurements for each combination. We present some toy models and simple worked examples. As an intermediate step, we give a precise meani...
Charming Mesons with Baryons and Nuclei
Tolos, Laura
2013-11-01
The properties of charmed mesons in nuclear matter and nuclei are reviewed. Different frameworks are discussed paying a special attention to unitarized coupled-channel approaches which incorporate heavy-quark spin symmetry. Several charmed baryon states with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. These states are compared to experimental data. Moreover, the properties of open-charm mesons in matter are analyzed. The in-medium solution accounts for Pauli blocking effects, and for the meson self-energies in a self-consistent manner. The behavior in the nuclear medium of the rich spectrum of dynamically-generated baryon states is studied as well as their influence in the self-energy and, hence, the spectral function of open charm. The possible experimental signatures of the in-medium properties of open charm are finally addressed, such as the formation of charmed nuclei, in connection with the future FAIR facility.
Charming mesons with baryons and nuclei
Tolos, Laura
2013-01-01
The properties of charmed mesons in nuclear matter and nuclei are reviewed. Different frameworks are discussed paying a special attention to unitarized coupled-channel approaches which incorporate heavy-quark spin symmetry. Several charmed baryon states with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with $1/2^+$ and $3/2^+$ baryons. These states are compared to experimental data. Moreover, the properties of open-charm mesons in matter are analyzed. The in-medium solution accounts for Pauli blocking effects, and for the meson self-energies in a self-consistent manner. The behavior in the nuclear medium of the rich spectrum of dynamically-generated baryon states is studied as well as their influence in the self-energy and, hence, the spectral function of open charm. The possible experimental signatures of the in-medium properties of open charm are finally addressed, such as the formation of charmed nuclei, in connection with the future F...
Baryons, Neutrinos, Feedback and Weak Gravitational Lensing
Harnois-Déraps, Joachim; Viola, Massimo; Heymans, Catherine
2014-01-01
(Abridged) The effect of baryonic feedback on the dark matter mass distribution is generally considered to be a nuisance to weak gravitational lensing. Measurements of cosmological parameters are affected as feedback alters the cosmic shear signal on angular scales smaller than a few arcminutes. Recent progress on the numerical modelling of baryon physics has shown that this effect could be so large that, rather than being a nuisance, the effect can be constrained with current weak lensing surveys, hence providing an alternative astrophysical insight on one of the most challenging questions of galaxy formation. In order to perform our analysis, we construct an analytic fitting formula that describes the effect of the baryons on the mass power spectrum. This fitting formula is based on three scenarios of the OWL hydrodynamical simulations. It is specifically calibrated for $z<1.5$, where it models the simulations to an accuracy that is better than $2\\%$ for scales $k<10 h\\mbox{Mpc}^{-1}$ and better than ...
Theoretical perspective for baryon number violation
International Nuclear Information System (INIS)
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 sin2theta/sub W/. It will be seen that the class of models involving an Su3 x SU2 x U1 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 SU5 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
Proton spin and baryon octet axial couplings
International Nuclear Information System (INIS)
Peripheral spin structure of the nucelon generated by the soft mesonic radiative corrections is studied within the light-cone perturbation theory. Starting with the tree-level SU(6) symmetry, we find a good description of the axial-vector couplings in β-decay of hyperons. We study the proton helicity flow from the baryonic core to the angular momentum of the pionic cloud. It is found that in the relativistic light-cone approach the spin-flip pattern is different from that in the coventional non-relativistic models. The axial-vector current matrix elements are shown to receive large corrections from beyond the conventional static limit. The important virtue of using the light-cone vertex functions of the meson-baryon Fock components of the proton is that the local gauge invariance and the energy-momentum sum rule are satisfied automatically. We infer the radius of the light-cone form factor from an analysis of the experimental data on the fragmentation of high-energy protons into nucleons and hyperons-the process dominated by stripping off the mesons of the meson-baryon Fock states. (orig.)
The Molecular Baryon Cycle of M82
Chisholm, John
2016-01-01
Baryons cycle into galaxies from the inter-galactic medium, are converted into stars, and a fraction of the baryons are ejected out of galaxies by stellar feedback. Here we present new high resolution (3.9"; 68 pc) CO(2-1) and CO(3-2) images that probe these three stages of the baryon cycle in the nearby starburst M 82. We combine these new observations with previous CO(1-0) and [Fe II] images to study the physical conditions within the molecular gas. Using a Bayesian analysis and the radiative transfer code RADEX, we model molecular Hydrogen temperatures and densities, as well as CO column densities. Besides the disc, we concentrate on two regions within the galaxy: an expanding super-bubble and the base of a molecular streamer. Shock diagnostics, kinematics, and optical extinction suggest that the streamer is an inflowing filament, with a molecular gas mass inflow rate of 3.5 M$_\\odot$ yr$^{-1}$. We measure the molecular gas mass outflow rate of the expanding super-bubble to be 17 M$_\\odot$ yr$^{-1}$, 5 tim...
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{\
Fragmentation Functions for Heavy Baryons in the Recombination Model
Institute of Scientific and Technical Information of China (English)
彭茹
2011-01-01
Using the shower parton distributions determined by the recombination model, we predict the fragmentation functions for heavy baryons. Then we obtain the completed fragmentation functions of heavy quarks (c and b) splitting into their hadrons (mesons and baryons containing one heavy valence quark). The calculated process shows that the fragmentation functions for mesons and baryons are not independent if the hadronization of the shower partons is taken into account.%Using the shower parton distributions determined by the recombination model,we predict the fragmentation functions for heavy baryons.Then we obtain the completed fragmentation functions of heavy quarks(c and b)splitting into their hadrons(mesons and baryons containing one heavy valence quark).The calculated process shows that the fragmentation functions for mesons and baryons are not independent if the hadronization of the shower partons is taken into account.
High statistics analysis using anisotropic clover lattices: (III) Baryon-baryon interactions
Energy Technology Data Exchange (ETDEWEB)
Beane, S; Detmold, W; Lin, H; Luu, T; Orginos, K; Savage, M; Torok, A; Walker-Loud, A
2010-01-19
Low-energy baryon-baryon interactions are calculated in a high-statistics lattice QCD study on a single ensemble of anisotropic clover gauge-field configurations at a pion mass of m{sub {pi}} {approx} 390 MeV, a spatial volume of L{sup 3} {approx} (2.5 fm){sup 3}, and a spatial lattice spacing of b {approx} 0.123 fm. Luescher's method is used to extract nucleon-nucleon, hyperon-nucleon and hyperon-hyperon scattering phase shifts at one momentum from the one- and two-baryon ground-state energies in the lattice volume. The isospin-3/2 N{Sigma} interactions are found to be highly spin-dependent, and the interaction in the {sup 3}S{sub 1} channel is found to be strong. In contrast, the N{Lambda} interactions are found to be spin-independent, within the uncertainties of the calculation, consistent with the absence of one-pion-exchange. The only channel for which a negative energy-shift is found is {Lambda}{Lambda}, indicating that the {Lambda}{Lambda} interaction is attractive, as anticipated from model-dependent discussions regarding the H-dibaryon. The NN scattering lengths are found to be small, clearly indicating the absence of any fine-tuning in the NN-sector at this pion mass. This is consistent with our previous Lattice QCD calculation of NN interactions. The behavior of the signal-to-noise ratio in the baryon-baryon correlation functions, and in the ratio of correlation functions that yields the ground-state energy splitting is explored. In particular, focus is placed on the window of time slices for which the signal-to-noise ratio does not degrade exponentially, as this provides the opportunity to extract quantitative information about multi-baryon systems.
Multi baryons with flavors in the Skyrme model
International Nuclear Information System (INIS)
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/mQ). The model predicts some narrow heavy flavored multi baryon states with baryon number four and seven. (author)
Detecting baryon acoustic oscillations by 3d weak lensing
Grassi, Alessandra; Schaefer, Bjoern Malte
2013-01-01
We investigate the possibility of detecting baryon acoustic oscillation features in the cosmic matter distribution by 3d weak lensing. Baryon oscillations are inaccessible even to weak lensing tomography because of wide line-of-sight weighting functions and require a specialized approach via 3d shear estimates. We quantify the uncertainty of estimating the matter spectrum amplitude at the baryon oscillations wave vectors by a Fisher-matrix approach with a fixed cosmology and show in this way ...
Quark-Pauli effects in three octet-baryons
Nakamoto, C
2016-01-01
To sustain a neutron star with about two times the solar mass, multi baryons including hyperons are expected to produce repulsive effects in the interior of its high baryon-density region. To examine possible quark-Pauli repulsion among the baryons, we solve the eigenvalue problem of the quark antisymmetrizer for three octet-baryons that are described by most compact spatial configurations. We find that the Pauli blocking effect is weak in the $\\Lambda nn$ system, while it is strong in the $\\Sigma^-nn$ system. The appearance of the $\\Sigma^-$ hyperon is suppressed in the neutron star interior but no quark-Pauli repulsion effectively works for the $\\Lambda$ hyperon.
Spectroscopy of singly, doubly, and triply bottom baryons
Wei, Ke-Wei; Liu, Na; Wang, Qian-Qian; Guo, Xin-Heng
2016-01-01
Recently, many singly bottom baryons have been established experimentally, but no doubly or triply bottom baryon has been observed. Under the Regge phenomenology, the mass of a ground state unobserved doubly or triply bottom baryon is expressed as a function of masses of the well established light baryons and singly bottom baryons. (For example, we write the mass of $\\Omega_{bbb}$ as a function of the masses of well established light baryons ($\\Sigma^{*}$, $\\Xi^{*}$, $\\Omega$) and singly bottom baryons ($\\Sigma_b^{*}$, $\\Xi_b^{*}$), and give its value to be 14788$\\pm$80 MeV.) After that, we calculate the values of Regge slopes and Regge intercepts for singly, doubly, and triply bottom baryons. (Regge intercepts and slopes, which are usually regarded as fundamental constants of hadron dynamics, are useful for many spectral and nonspectral purposes.) Then, masses of the orbitally excited singly, doubly, and triply bottom baryons are estimated. The isospin splitting is also determined, $M_{\\Xi_{bb}^{-}}-M_{\\Xi_{...
Hypermagnetic Fields and Baryon Asymmetry from Pseudoscalar Inflation
Anber, Mohamed M
2015-01-01
We show that maximally helical hypermagnetic fields produced during pseudoscalar inflation can generate the observed baryon asymmetry of the universe via the B+L anomaly in the Standard Model. We find that most of the parameter space of pseudoscalar inflation that explains the cosmological data leads to baryon overproduction, hence the models of natural inflation are severely constrained. We also point out a connection between the baryon number and topology of the relic magnetic fields. Both the magnitude and sign of magnetic helicity can be detected in future diffuse gamma ray data. This will be a smoking gun evidence for a link between inflation and the baryon asymmetry of the Universe.
Interrelations between baryon trajectories and new mass formulas for baryon octet
International Nuclear Information System (INIS)
In the framework of the dual analytic model the interrelations between Regge slopes and intercepts for baryon octet are obtained. The relations agree well with experiment and lead to new mass formulas for octets 1/2sup(+), 1/2sup(-) and their angular excitations
Octet baryon masses and sigma terms in covariant baryon chiral perturbation theory
Ren, Xiu-Lei; Meng, Jie
2015-01-01
We report on a recent study of the ground-state octet baryon masses and sigma terms in covariant baryon chiral perturbation theory with the extended-on-mass-shell scheme up to next-to-next-to-next-to-leading order. To take into account lattice QCD artifacts, the finite-volume corrections and finite lattice spacing discretization effects are carefully examined. We performed a simultaneous fit of all the $n_f = 2+1$ lattice octet baryon masses and found that the various lattice simulations are consistent with each other. Although the finite lattice spacing discretization effects up to $\\mathcal{O}(a^2)$ can be safely ignored, but the finite volume corrections cannot even for configurations with $M_\\phi L>4$. As an application, we predicted the octet baryon sigma terms using the Feynman-Hellmann theorem. In particular, the pion- and strangeness-nucleon sigma terms are found to be $\\sigma_{\\pi N} = 55(1)(4)$ MeV and $\\sigma_{sN} = 27(27)(4)$ MeV, respectively.
Extended-soft-core Baryon-Baryon Model ESC08 I. Nucleon-Nucleon Scattering
Nagels, M M; Yamamoto, Y
2014-01-01
The Nijmegen extended-sft-core ESC08c model for the baryon-baryon (BB) interactions of the SU(3) flavor-octet of baryons ($N, \\Lambda, \\Sigma$, and $\\Xi$) is presented. In this first of a series of papers, the NN results are reported in detail. In the spirit of the Yukawa-approach to the nuclear force problem, the interactions are studied from the meson-exchange picture viewpoint, 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. The extended-soft-core (ESC) meson-exchange interactions consist of local- and non-local-potentials due to ((i) One-boson-exchanges (OBE, which are the members of nonets of pseudoscalar , vector, scalar, and axial-vector mesons, (ii) diffractive (i.e. multiple-gluon) exchanges, (iii) two pseudoscalar exchange (PS-PS), and (iv) meson-pair-exchange (MPE). The OBE- and MPE-vertices are regulated by gaussian form factors producing potentials with a soft beha...
BARYON LOADED RELATIVISTIC BLAST WAVES IN SUPERNOVAE
International Nuclear Information System (INIS)
We provide a new analytic blast wave solution which generalizes the Blandford-McKee solution to arbitrary ejecta masses and Lorentz factors. Until recently relativistic supernovae have been discovered only through their association with long-duration gamma-ray bursts (GRBs). The blast waves of such explosions are well described by the Blandford-McKee (in the ultra-relativistic regime) and Sedov-Taylor (in the non-relativistic regime) solutions during their afterglows, as the ejecta mass is negligible in comparison to the swept-up mass. The recent discovery of the relativistic supernova SN 2009bb, without a detected GRB, opens up the possibility of highly baryon loaded, mildly relativistic outflows which remains in nearly free-expansion phase during the radio afterglow. In this work, we consider a massive, relativistic shell, launched by a Central Engine Driven EXplosion (CEDEX), decelerating adiabatically due to its collision with the pre-explosion circumstellar wind profile of the progenitor. We compute the synchrotron emission from relativistic electrons in the shock amplified magnetic field. This models the radio emission from the circumstellar interaction of a CEDEX. We show that this model explains the observed radio evolution of the prototypical SN 2009bb and demonstrate that SN 2009bb had a highly baryon loaded, mildly relativistic outflow. We discuss the effect of baryon loading on the dynamics and observational manifestations of a CEDEX. In particular, our predicted angular size of SN 2009bb is consistent with very long baseline interferometric (VLBI) upper limits on day 85, but is presently resolvable on VLBI angular scales, since the relativistic ejecta is still in the nearly free-expansion phase.
Dynamical twisted mass fermions and baryon spectroscopy
International Nuclear Information System (INIS)
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)
Time delay plots of unflavoured baryons
Kelkar, N. G.; Nowakowski, M.; Khemchandani, K. P.; Jain, S. R.
2004-01-01
We explore the usefulness of the existing relations between the S-matrix and time delay in characterizing baryon resonances in pion-nucleon scattering. We draw attention to the fact that the existence of a positive maximum in time delay is a necessary criterion for the existence of a resonance and should be used as a constraint in conventional analyses which locate resonances from poles of the S-matrix and Argand diagrams. The usefulness of the time delay plots of resonances is demonstrated through a detailed analysis of the time delay in several partial waves of πN elastic scattering.
Cosmology with X-ray Cluster Baryons
Energy Technology Data Exchange (ETDEWEB)
Linder, Eric V.
2007-04-10
X-ray cluster measurements interpreted with a universal baryon/gas mass fraction can theoretically serve as a cosmological distance probe. We examine issues of cosmological sensitivity for current (e.g., Chandra X-ray Observatory, XMM-Newton) and next generation (e.g., Con-X, XEUS) observations, along with systematic uncertainties and biases. To give competitive next generation constraints on dark energy, we find that systematics will need to be controlled to better than 1percent and any evolution in f_gas (and other cluster gas properties) must be calibrated so the residual uncertainty is weaker than (1+z)0.03.
Notes on anomalies, baryons, and Seiberg duality
Corley, Steven
2003-01-01
We consider an N=1 SU(N_c) SUSY gauge theory with N_f \\geq N_c matter multiplets transforming in the fundamental and antifundamental representations of the gauge group. Using the Konishi anomaly and a non-anomalous conservation law, we derive a system of partial differential equations that determine the low energy effective superpotential as a function of the mesonic and baryonic vacuum expectation values. We apply the formalism to the cases of N_f = N_c and N_f = N_c +1 where the equations a...
Non-Baryonic Dark Matter in Cosmology
Del Popolo, A
2014-01-01
This paper is a broad-band review of the current status of non-baryonic dark matter research. I start with a historical overview of the evidences of dark matter existence, then I discuss how dark matter is distributed from small scale to large scale, and I then verge the attention to dark matter nature: dark matter candidates and their detection. I finally discuss some of the limits of the $\\Lambda$CDM model, with particular emphasis on the small scale problems of the paradigm.
ABJM Baryon Stability and Myers effect
Lozano, Yolanda; Sfetsos, Konstadinos; Siampos, Konstadinos
2011-01-01
We consider magnetically charged baryon vertex like configurations in AdS^4 X CP^3 with a reduced number of quarks l. We show that these configurations are solutions to the classical equations of motion and are stable beyond a critical value of l. Given that the magnetic flux dissolves D0-brane charge it is possible to give a microscopical description in terms of D0-branes expanding into fuzzy CP^n spaces by Myers dielectric effect. Using this description we are able to explore the region of finite 't Hooft coupling.
Baryon instability search in large detectors
International Nuclear Information System (INIS)
Nucleon decay appears as a consequence of models trying to explain the baryon-antibaryon asymmetry. This has motivated 15 years ago many underground experiments devoted to the search of proton and neutron decay. A very large number of decay channels have been investigated and no evidence has been found yielding lower limits on lifetime which rule out the minimal SU(5) Grand Unified Theory predictions and put severe constraints on more complicated models. Next generation experiments like Super-Kamiokande, which is starting to take data now, ICARUS, whose a 600 ton prototype is under construction, will be sensitive to more complicated models predicting larger lifetimes. (author)
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
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.
Electromagnetic moments of quasi-stable baryons
Ledwig, T.; Martin-Camalich, J.; Pascalutsa, V.; Vanderhaeghen, M.
2011-01-01
We address electromagnetic properties of quasi-stable baryons in the context of chiral extrapolations of lattice QCD results. For particles near their decay threshold we show that the application of a small external magnetic field changes the particle's energy in a non-analytic way. Conventional electromagnetic moments are only well-defined when the background field B satisfies |eB|/(2M_*|M_*-M-m|) where M_* is the mass of the resonance and M, m the masses of the decay products. An applicatio...
Quasinuclear states in baryon-antibaryon systems
International Nuclear Information System (INIS)
A review of modern state of physics of quasinuclear baryon-antibarion systems (''baryonium'') is presented. The comparison between the theory predictions and recent experimental data is carried out. Discrete γ - spectrum from the anti pp annihilation, annihilation and elastic widths for N anti N resonances from experiments with hydrogen and deuterium targets, proton form factor and e+e- annihilation in the vicinity of N anti N threshold are considered. The most important future experiments on antiproton annihilation in nuclear targers are discussed. Experiments which may reveal the existences of 2B anti B and 2B anti 2B systems are predicted
Non-Baryonic Dark Matter in Cosmology
Del Popolo, A.
2013-01-01
This paper is a broad-band review of the current status of non-baryonic dark matter research. I start with a historical overview of the evidences of dark matter existence, then I discuss how dark matter is distributed from small scale to large scale, and I then verge the attention to dark matter nature: dark matter candidates and their detection. I finally discuss some of the limits of the $\\Lambda$CDM model, with particular emphasis on the small scale problems of the paradigm.
High Statistics Analysis using Anisotropic Clover Lattices: (III) Baryon-Baryon Interactions
Energy Technology Data Exchange (ETDEWEB)
Beane, Silas [Univ. of New Hampshire, Durham, NH (United States); Detmold, William [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Lin, Huey-Wen [Univ. of Washington, Seattle, WA (United States); Luu, Thomas C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Orginos, Kostas [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Savage, Martin [Univ. of Washington, Seattle, WA (United States); Torok, Aaron M. [Indiana Univ., Bloomington, IN (United States). Dept. of Physics; Walker-Loud, Andre [College of William and Mary, Williamsburg, VA (United States)
2010-03-01
Low-energy baryon-baryon interactions are calculated in a high-statistics lattice QCD study on a single ensemble of anisotropic clover gauge-field configurations at a pion mass of m_pi ~ 390 MeV, a spatial volume of L^3 ~ (2.5 fm)^3, and a spatial lattice spacing of b ~ 0.123 fm. Luscher’s method is used to extract nucleon-nucleon, hyperon-nucleon and hyperon-hyperon scattering phase shifts at one momentum from the one- and two-baryon ground-state energies in the lattice volume. The N-Sigma interactions are found to be highly spin-dependent, and the interaction in the ^3 S _1 channel is found to be strong. In contrast, the N-Lambda interactions are found to be spin-independent, within the uncertainties of the calculation, consistent with the absence of one-pion-exchange. The only channel for which a negative energy-shift is found is Lambda-Lambda, indicating that the Lambda-Lambda interaction is attractive, as anticipated from model-dependent discussions regarding the H-dibaryon. The NN scattering lengths are found to be small, clearly indicating the absence of any fine-tuning in the NN-sector at this pion mass. This is consistent with our previous Lattice QCD calculation of the NN interactions. The behavior of the signal-to-noise ratio in the baryon-baryon correlation functions, and in the ratio of correlation functions that yields the ground-state energy splitting
Evidence for chiral logarithms in the baryon spectrum
Walker-Loud, Andre
2011-01-01
Using precise lattice QCD computations of the baryon spectrum, we present the first direct evidence for the presence of contributions to the baryon masses which are non-analytic in the light quark masses; contributions which are often denoted "chiral logarithms". We isolate the poor convergence of SU(3) baryon chiral perturbation theory to the flavor-singlet mass combination. The flavor-octet baryon mass splittings, which are corrected by chiral logarithms at next to leading order in SU(3) chiral perturbation theory, yield baryon-pion axial coupling constants D, F, C and H consistent with QCD values; the first evidence of chiral logarithms in the baryon spectrum. The Gell-Mann--Okubo relation, a flavor-27 baryon mass splitting, which is dominated by chiral corrections from light quark masses, provides further evidence for the presence of non-analytic light quark mass dependence in the baryon spectrum; we simultaneously find the GMO relation to be inconsistent with the first few terms in a taylor expansion in ...
An Attempt to Study Pentaquark Baryons in String Theory
Sugamoto, Akio
2004-01-01
An attempt to study recently observed Pentaquark baryons is performed in the dual string theory of QCD. Mass formulae for Pentaquark baryons are naively estimated in the Maldacena's prototype model for supersymmetric QCD and a more realistic model for the ordinary QCD.
SU(4) breaking for semileptonic decays of charmed baryons
Energy Technology Data Exchange (ETDEWEB)
Buccella, F.; Sciarrino, A.; Sorba, P.
1978-08-01
The effects of SU(4) breaking are studied in connection with the semileptonic decays and magnetic moments of the baryons with charm + 1. Substantial suppression factors are predicted for the decay in which the final baryon belongs to the decimet. The consequences of a vanishing magnetic moment for the charmed quark are studied in detail.
SU(4) breaking for semileptonic decays of charmed baryons
International Nuclear Information System (INIS)
The effects of SU(4) breaking are studied in connection with the semileptonic decays and magnetic moments of the baryons with charm + 1. Substantial suppression factors are predicted for the decay in which the final baryon belongs to the decimet. The consequences of a vanishing magnetic moment for the charmed quark are studied in detail
Electromagnetic form factors of octet baryons in QCD
International Nuclear Information System (INIS)
The electromagnetic form factors of octet baryons are estimated within light cone QCD sum rules method, using the most general form of the interpolating current for baryons. A comparison of our predictions on the magnetic dipole and electric form factors with the results of other approaches is performed
Diquark Structure in Heavy Quark Baryons in a Geometric Model
Paria, Lina; Abbas, Afsar
1996-01-01
Using a geometric model for the study of the structure of hadrons, we study baryons having one, two and three heavy quarks. The study reveals diquark structure in baryons with one and two heavy quarks but not with three heavy identical quarks.
Unifying Nucleon and Quark Dynamics at Finite Baryon Number Density
Meyer, J.; Schwenzer, K.; Pirner, H. -J.
1999-01-01
We present a model of baryonic matter which contains free constituent quarks in addition to bound constituent quarks in nucleons. In addition to the common linear sigma-model we include the exchange of vector-mesons. The percentage of free quarks increases with baryon density but the nucleons resist a restoration of chiral symmetry.
Soliton solutions of Chiral Born-Infeld Theory and baryons
Pavlovsky, Oleg V.
2003-01-01
Finite-energy topological spherically symmetrical solutions of Chiral Born-Infeld Theory are studied. Properties of these solution are obtained, and a possible physical interpretation is also given. We compute static properties of baryons (mass,main radius, magnetic main radius, axial coupling constant) whose solutions can be interpreted as the baryons of QCD.
Electroproduction of Baryon Resonances and Strangeness Suppression
Santopinto, E; Tecocoatzi, H Garcia
2016-01-01
We describe the electroproduction ratios of baryon-meson states from nucleon using an extension of the quark model that takes into account the sea. As a result we provide, with no adjustable parameters, the predictions of ratios of exclusive meson-baryon final states: Lambda K , Sigma K, p pion, and n pion. These predictions are in agreement with the new Jlab experimental data showing that sea quarks play an important role in the electroproduction. We also predicted further ratios of exclusive reactions that can be measured and tested in future experiments. In particular, we suggested new experiments on deuterium and tritium. Such measurements can provide crucial test of different predictions concerning the structure of nucleon and its sea quarks helping to solve an outstanding problem. Finally, we computed the so called strangeness suppression factor, lambda s, that is the suppression of strange quark-antiquarks compared to nonstrange pairs, and we found that our finding with this simple extension of the qua...
Baryon masses with dynamical twisted mass fermions
Alexandrou, C; Koutsou, G; Baron, R; Guichon, P; Brinet, M; Carbonell, J; Drach, V; Liu, Z; Pène, O; Urbach, C
2007-01-01
We present results on the mass of the nucleon and the $\\Delta$ using two dynamical degenerate twisted mass quarks. The evaluation is performed at four quark masses corresponding to a pion mass in the range of 690-300 MeV on lattices of size 2.1 fm and 2.7 fm. We check for cutoff effects by evaluating these baryon masses on lattices of spatial size 2.1 fm with lattice spacings $a(\\beta=3.9)=0.0855(6)$ fm and $a(\\beta=4.05)=0.0666(6)$ fm, determined from the pion sector and find them to be within our statistical errors. Lattice results are extrapolated to the physical limit using continuum chiral perturbation theory. The nucleon mass at the physical point provides a determination of the lattice spacing. Using heavy baryon chiral perturbation theory at ${\\cal O}(p^3)$ we find $a(\\beta=3.9)=0.0879(12)$ fm, with a systematic error due to the chiral extrapolation estimated to be about the same as the statistical error. This value of the lattice spacing is in good agreement with the value determined from the pion se...
Universal fitting formulae for baryon oscillation surveys
Blake, Chris; Parkinson, David; Bassett, Bruce; Glazebrook, Karl; Kunz, Martin; Nichol, Robert C.
2006-01-01
The next generation of galaxy surveys will attempt to measure the baryon oscillations in the clustering power spectrum with high accuracy. These oscillations encode a preferred scale which may be used as a standard ruler to constrain cosmological parameters and dark energy models. In this paper we present simple analytical fitting formulae for the accuracy with which the preferred scale may be determined in the tangential and radial directions by future spectroscopic and photometric galaxy redshift surveys. We express these accuracies as a function of survey parameters such as the central redshift, volume, galaxy number density and (where applicable) photometric redshift error. These fitting formulae should greatly increase the efficiency of optimizing future surveys, which requires analysis of a potentially vast number of survey configurations and cosmological models. The formulae are calibrated using a grid of Monte Carlo simulations, which are analysed by dividing out the overall shape of the power spectrum before fitting a simple decaying sinusoid to the oscillations. The fitting formulae reproduce the simulation results with a fractional scatter of 7 per cent (10 per cent) in the tangential (radial) directions over a wide range of input parameters. We also indicate how sparse-sampling strategies may enhance the effective survey area if the sampling scale is much smaller than the projected baryon oscillation scale.
A model for net-baryon rapidity distribution
Alvarez-Muñiz, J; Dias de Deus, J; Santo, M C Espírito; Milhano, J G; Pimenta, M
2009-01-01
In nuclear collisions, a sizable fraction of the available energy is carried away by baryons. As the baryon number is conserved, the net-baryon $B-\\bar{B}$ retains information on the energy-momentum carried by the incoming nuclei. A simple and consistent model for net-baryon production in high energy proton-proton and nucleus-nucleus collisions is presented. The basic ingredients of the model are valence string formation based on standard PDFs with QCD evolution and string fragmentation via the Schwinger mechanism. The results of the model are presented and compared with data at different centre-of-mass energies and centralities, as well as with existing models. These results show that a good description of the main features of net-baryon data is possible in the framework of a simplistic model, with the advantage of making the fundamental production mechanisms manifest.
A model for net-baryon rapidity distribution
International Nuclear Information System (INIS)
In nuclear collisions, a sizable fraction of the available energy is carried away by baryons. As baryon number is conserved, the net-baryon B- anti B retains information on the energy-momentum carried by the incoming nuclei. A simple and consistent model for net-baryon production in high energy proton-proton and nucleus-nucleus collisions is presented. The basic ingredients of the model are valence string formation based on standard PDFs with QCD evolution and string fragmentation via the Schwinger mechanism. The results of the model are presented and compared with data at different centre-of-mass energies and centralities, as well as with existing models. These results show that a good description of the main features of the net-baryon data is possible in the framework of a simplistic model, with the advantage of making the fundamental production mechanisms manifest. (orig.)
Magnetic moments of charm baryons in chiral perturbation theory
International Nuclear Information System (INIS)
Magnetic moments of the charm baryons of the sextet and of the 3*-plet are re-evaluated in the framework of Heavy Hadron Chiral Perturbation Theory (HHCPT). NRQM and broken SU(4) unitary symmetry model are used to obtain tree-level magnetic moments. Calculations of a unitary symmetry part of one-loop contributions to magnetic moments of the charm baryons are performed in detail in terms of the SU(4) couplings of charm baryons to Goldstone bosons. The relations between the magnetic moments of the sextet 1/2 baryons with the one-loop corrections are shown to coincide with the NRQM relations. The correspondence between HHCPT results and those of NRQM and unitary symmetry model is discussed. It is shown that one-loop corrections can effectively be absorbed into the tree-level formulae for the magnetic moments of the charm baryons in the broken SU(4) unitary symmetry model and partially in the NRQM. (author)
International Nuclear Information System (INIS)
The recent quark-model baryon-baryon interaction by the Kyoto-Niigata group is applied to the triton, hypertriton, 2αΛ and 2Λα systems, in which a new three-cluster Faddeev formalism, using the 2-cluster resonating-group method (RGM) kernel, is developed for the exact treatment of the Pauli forbidden states between cluster. (author)
Phenomenological sizes of confinement regions in baryons
International Nuclear Information System (INIS)
Standard order of magnitude estimates from QCD indicate that the radius of the quark-gluon core in the nucleon is Λ-1QCD > or approx. 1 fm. However, in work with the chiral bag model, we have found that the effective confinement size for low energy reactions can be as small as ≅ 1/2 fm or smaller. This shrinking of the effective confinement size has been attributed to the pressure of the pion cloud surrounding the quark core. The concept of confinement size is evidently subtle in light-quark systems, due to the chiral vacuum structure. This is indicated by the 'Cheshire Cat' phenomenon, in which physical observables tend to be insensitive to the bag radius R. We suggest that when strange quarks are present, a qualitative change occurs in the Cheshire Cat picture; in particular, we propose that strangeness provides an obstruction to this picture. We present a phenomenological indication that when strange quarks are present, the bag radius R is frozen at a value substantially larger than 0.5 fm by as much as a factor of two. Roughly speaking, the Cheshire Cat picture emerges from a near cancellation between repulsive quark kinetic and attractive pion-cloud energies in the case of the nucleon. In the Λ and Σ particles, however, replacement of one up or down quark by a strange quark removes ≅ 1/Nc of the attraction from the coupling of the quarks to the pion cloud. This upsets the balance needed for the Cheshire Cat phenomenon and makes larger strange baryons more favorable energetically than the 0.5 fm ones appropriate for pure u- and d-systems. We find that magnetic moments of strange baryons favor a bag radius R ≅ 1.1 fm. We find that the excited states of the Λ-hyperons favor similarly large bag radii. Somewhat less convincingly, we argue that - due to perturbative effects - the bag radius appropriate to the Δ(1232) lies intermediate between that of the nucleon and of the strange baryons. (orig.)
Baryon-baryon interactions described by the WKB-RGM quark-model potential
International Nuclear Information System (INIS)
We investigate the baryon-baryon interactions predicted by the Kyoto-Niigata quark model, by using phase-shift equivalent local potentials obtained in the WKB-RGM method. The effect of flavor symmetry breaking is discussed by comparing the 1S0 potentials among the NN, ΣN(I=3/2), ΣΣ(I=2), ΞΣ(I=3/2) and ΞΞ(I=1) systems, which possess the simple flavor SU3 symmetry (22). It is characterized by the detailed balance between the reduction of the short-range repulsion, generated from the color-magnetic term, and the reduction of the medium-range attraction, generated from scalar-meson exchange. A special role of the Bryan-Scott term in the model fss2 is emphasized. (author)
Quark-Model Baryon-Baryon Interaction and its Applications to Hypernuclei
Fujiwara, Y; Suzuki, Y; Kohno, M; Miyagawa, K
2004-01-01
The quark-model baryon-baryon interaction fss2, proposed by the Kyoto-Niigata group, is a unified model for the complete baryon octet (B_8=N, Lambda, Sigma and Xi), which is formulated in a framework of the (3q)-(3q) resonating-group method (RGM) using the spin-flavor SU_6 quark-model wave functions and effective meson-exchange potentials at the quark level. Model parameters are determined to reproduce properties of the nucleon-nucleon system and the low-energy cross section data for the hyperon-nucleon scattering. Due to the several improvements including the introduction of vector-meson exchange potentials, fss2 has achieved very accurate description of the NN and YN interactions, comparable to various one-boson exchange potentials. We review the essential features of fss2 and our previous model FSS, and their predictions to few-body systems in confrontation with the available experimental data. Some characteristic features of the B_8 B_8 interactions with the higher strangeness, S=-2, -3, -4, predicted by ...
Mirage in Temporal Correlation functions for Baryon-Baryon Interactions in Lattice QCD
Iritani, Takumi; Aoki, Sinya; Gongyo, Shinya; Hatsuda, Tetsuo; Ikeda, Yoichi; Inoue, Takashi; Ishii, Noriyoshi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji
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 the 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 ($\\Xi\\Xi$ and $NN$), and three and four baryons ($^3{\\rm He}$ and $^4{\\rm He})$ as well, employing (2+1)-flavor lattice QCD at $m_{\\pi}=0.51$ GeV on four lattice volumes with $L=$ 2.9, 3.6, 4.3 and 5.8 fm. Caution is given for drawing conclusion on the bound $NN$, $3N$ and $4N$ systems only based on the temporal correlation functions.
Cluster outskirts and the missing baryons
Eckert, D.
2016-06-01
Galaxy clusters are located at the crossroads of intergalactic filaments and are still forming through the continuous merging and accretion of smaller structures from the surrounding cosmic web. Deep, wide-field X-ray studies of the outskirts of the most massive clusters bring us valuable insight into the processes leading to the growth of cosmic structures. In addition, cluster outskirts are privileged sites to search for the missing baryons, which are thought to reside within the filaments of the cosmic web. I will present the XMM cluster outskirts project, a VLP that aims at mapping the outskirts of 13 nearby clusters. Based on the results obtained with this program, I will then explore ideas to exploit the capabilities of XMM during the next decade.
Soft RPV Through the Baryon Portal
Krnjaic, Gordan
2013-01-01
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 ...
Color From Geometry (strings, Fivebrane, Baryon, Fourbrane)
Guijosa, A
1999-01-01
This thesis explores some aspects of the recently uncovered connection between gauge theories and gravity, known as the AdS /CFT, or bulk-boundary, correspondence. This is a remarkable statement of equivalence between string or M-theory on certain backgrounds and field theories living on the boundaries of the corresponding spacetimes. Under the duality between four-dimensional N = 4 wrapped D5-brane. We examine the structure and energetics of this system from the vantage point of the fivebrane worldvolume action, making use of the Born-Infeld string approach. We construct supersymmetric fivebrane embeddings N D3-branes provides a detailed description of the creation of strings as the fivebrane is dragged across the threebranes. We also study baryon configurations in large N non- supersymmetric gauge theories...
First observation of doubly charmed baryons
Energy Technology Data Exchange (ETDEWEB)
M. A. Moinester et al.
2003-09-25
The SELEX experiment (E781) at Fermilab has observed two statistically compelling high mass states near 3.6 GeV/c{sup 2}, decaying to {Lambda}{sub c}{sup +} K{sup -} {pi}{sup +} and {Lambda}{sub c}{sup +} K{sup -} {pi}{sup +}{pi}{sup +}. These final states are Cabibbo-allowed decay modes of doubly charmed baryons {Xi}{sub cc}{sup +} and {Xi}{sub cc}{sup ++}, respectively. The masses are in the range expected from theoretical considerations, but the spectroscopy is surprising. SELEX also has weaker preliminary evidence for a state near 3.8 GeV/c{sup 2}, a high mass state decaying to {Lambda}{sub c}{sup +} K{sup -} {pi}{sup +}{pi}{sup +}, possibly an excited {Xi}{sub cc}{sup ++} (ccu*). Data are presented and discussed.
How do galaxies get their baryons?
Conselice, Christopher J
2011-01-01
Understanding how galaxies obtain baryons, their stars and gas, over cosmic time is traditionally approached in two different ways - theoretically and observationally. In general, observational approaches to galaxy formation include measuring basic galaxy properties, such as luminosities, stellar masses, rotation speeds, star formation rates and how these features evolve through time. Theoretically, cosmologically based models collate the physical effects driving galaxy assembly - mergers of galaxies, accretion of gas, star formation, and feedback, amongst others, to form predictions which are matched to galaxy observables. An alternative approach is to examine directly, in an observational way, the processes driving galaxy assembly, including the effects of feedback. This is a new `third way' towards understanding how galaxies are forming from gas accretion and mergers, and directly probes these effects instead of relying on simulations designed to reproduce observations. This empirical approach towards unde...
'Nonbaryonic' dark matter as baryonic colour superconductor
International Nuclear Information System (INIS)
We discuss a novel cold dark matter candidate which is formed from the ordinary quarks during the QCD phase transition when the axion domain wall undergoes an unchecked collapse due to the tension in the wall. If a large number of quarks is trapped inside the bulk of a closed axion domain wall, the collapse stops due to the internal Fermi pressure. In this case the system in the bulk, may reach the critical density when it undergoes a phase transition to a colour superconducting phase with the ground state being the quark condensate, similar to BCS theory. If this happens, the new state of matter representing the diquark condensate with a large baryon number B ∼ 1032 becomes a stable soliton-like configuration. Consequently, it may serve as a novel cold dark matter candidate
Baryon number violation in high energy collisions
International Nuclear Information System (INIS)
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.)
Baryon Loaded Relativistic Blastwaves in Supernovae
Chakraborti, Sayan
2010-01-01
We provide a new analytic blastwave solution which generalizes the Blandford-McKee solution to arbitrary ejecta masses and Lorentz factors. Until recently relativistic supernovae have been discovered only through their association with long duration Gamma Ray Bursts (GRB). The blastwaves of such explosions are well described by the Blandford-McKee (in the ultra relativistic regime) and Sedov-Taylor (in the non-relativistic regime) solutions during their afterglows, as the ejecta mass is negligible in comparison to the swept up mass. The recent discovery of the relativistic supernova SN 2009bb, without a detected GRB, opens up the possibility of highly baryon loaded mildly relativistic outflows which remains in nearly free expansion phase during the radio afterglow. In this work, we consider a massive, relativistic shell, launched by a Central Engine Driven EXplosion (CEDEX), decelerating due to its collision with the pre-explosion circumstellar wind of the progenitor. We compute the synchrotron emission from ...
Baryon operators of higher twist in QCD
International Nuclear Information System (INIS)
In hard QCD processes the effects of higher twist contributions correspond to corrections which are suppressed by powers of the hard scale and are therefore relevant if high accuracy is required. The scale dependence of a physical observable is governed by the renormalization of the higher-twist operators. In the case of baryon operators the anomalous dimensions of the operators of twist 3 have been studied numerously and an almost complete understanding has been achieved. However, starting with twist 4 non-quasipartonic operators (i.e. operators whose twist is larger than their number of parton fields) enter the game and the number of independent operators increases significantly. Making heavy use of conformal symmetry, which prescribes the one-loop renormalization to a certain extent, we see that the construction of an advantageous operator basis is possible and the full spectrum of anomalous dimensions can be obtained
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.
Baryon transition form factors at the pole
Tiator, L; Workman, R L; Hadžimehmedović, M; Osmanović, H; Omerović, R; Stahov, J; Švarc, A
2016-01-01
Electromagnetic resonance properties are uniquely defined at the pole and do not depend on the separation of the resonance from background or the decay channel. Photon-nucleon branching ratios are nowadays often quoted at the pole, and we generalize the considerations to the case of virtual photons. We derive and compare relations for nucleon to baryon transition form factors both for the Breit-Wigner and the pole positions. Using the MAID2007 and SAID SM08 partial wave analyses of pion electroproduction data, we compare the $G_M$, $G_E$, and $G_C$ form factors for the $\\Delta(1232)$ resonance excitation at the Breit-Wigner resonance and pole positions up to $Q^2=5$ GeV$^2$. We also explore the $E/M$ and $S/M$ ratios as functions of $Q^2$. For pole and residue extraction, we apply the Laurent + Pietarinen method.
Leptogenesis and gravity: baryon asymmetry without decays
McDonald, J I
2016-01-01
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.
Light baryon spectrum using improved interpolating operators
Energy Technology Data Exchange (ETDEWEB)
S. Basak, R. G. Edwards, G. T. Fleming, J. Juge, A. Lichtl, C. Morningstar D. G. Richards, I. Sato, S. J. Wallace
2006-06-26
Energies for excited light baryons are computed in quenched QCD with a pion mass of 490 MeV. Operators used in the simulations include local operators and the simplest nonlocal operators that have nontrivial orbital structures. All operators are designed with the use of Clebsch-Gordan coefficients of the octahedral group so that they transform irreducibly under the group rotations. Matrices of correlation functions are computed for each irreducible representation, and then the variational method is applied to separate mass eigenstates. We obtained 17 states for isospin 1/2 and 11 states for isospin 3/2 in various spin-parity channels including J{sup P}=5/2{sup {+-}}. The pattern of the lowest-lying energies from each irrep is discussed. We use anisotropic lattices of volume 24{sup 3} x 64 with temporal lattice spacing a{sub t}{sup -1}=6.05 GeV with renormalized anisotropy xi=3.0.
Quantum Operator Design for Lattice Baryon Spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Lichtl, Adam
2007-09-06
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.
Universal fitting formulae for baryon oscillation surveys
Blake, C; Bassett, B; Glazebrook, K; Kunz, M; Nichol, R C; Blake, Chris; Parkinson, David; Bassett, Bruce; Glazebrook, Karl; Kunz, Martin; Nichol, Robert C.
2006-01-01
The next generation of galaxy surveys will attempt to measure the baryon oscillations in the clustering power spectrum with high accuracy. These oscillations encode a preferred scale which may be used as a standard ruler to constrain cosmological parameters and dark energy models. In this paper we present simple analytical fitting formulae for the accuracy with which the preferred scale may be determined in the tangential and radial directions by future spectroscopic and photometric galaxy redshift surveys. We express these accuracies as a function of survey parameters such as the central redshift, volume, galaxy number density and (where applicable) photometric redshift error. These fitting formulae should greatly increase the efficiency of optimizing future surveys, which requires analysis of a potentially vast number of survey configurations and cosmological models. The formulae are calibrated using a grid of Monte Carlo simulations, which are analyzed by dividing out the overall shape of the power spectru...
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.
Isospin breaking in octet baryon mass splittings
International Nuclear Information System (INIS)
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.
Synthesis of baryons from unconfined quarks
International Nuclear Information System (INIS)
The cosmic temperature at which primordial quarks condense into baryons is calculated for a number of cases within a field theory of partially confined quarks that enjoys temporary asymptotic freedom. It is assumed that the mass of a quark in a dense quark anti-quark medium is a monotonic function of the medium, that is, that the so-called Archimedes effect is valid. It is shown that, within such models, unbound quark lifetimes are larger than the age of the universe at the time of the transition and that the Archimedes effect implies that the change of the medium from free to bound quarks is a phase transition. 1 figure, 1 table
Hong, D K; Yee, H U; Hong, Deog Ki; Inami, Takeo; Yee, Ho-Ung
2007-01-01
We construct a holographic model for baryons in the context of AdS/QCD and study the spin-1/2 nucleon spectra and its couplings to mesons, taking fully account of the effects from the chiral symmetry breaking. A pair of 5D spinors is introduced to represent both left and right chiralities. Our model contains two adjustable parameters, the infrared cutoff and the Yukawa coupling of bulk spinors to bulk scalars, corresponding to the order parameter of chiral symmetry. Taking the lowest-lying nucleon mass as an input, we calculate the mass spectrum of excited nucleons and the nucleon couplings to pions. The excited nucleons show a parity-doubling pattern with smaller pion-nucleon couplings.
Observation of excited $\\Lambda^0_b$ baryons
Aaij, R; 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 $\\Lambda_b^{*0}(5920)$.
An interacting quark-diquark model. Strange and nonstrange baryon spectroscopy and other observables
De Sanctis, M; Vsevolodovna, R Magaña; Saracco, P; Santopinto, E
2016-01-01
We describe the relativistic interacting quark-diquark model formalism and its application to the calculation of strange and nonstrange baryon spectra. The results are compared to the existing experimental data. We also discuss the application of the model to the calculation of other baryon observables, like baryon magnetic moments, open-flavor strong decays and baryon masses with self-energy corrections.
Three body resonances in two meson-one baryon systems
Martínez Torres, Alberto; Khemchandani, K. P.; Oset Báguena, Eulogio
2007-01-01
We report four $\\Sigma$'s and three $\\Lambda$'s, in the 1500 - 1800 MeV region, as two meson - one baryon S-wave $(1/2)^+$ resonances. We solve Faddeev equations in the coupled channel approach. The invariant mass of one of the meson-baryon pairs and that of the three particles have been varied and peaks in the squared three body $T$-matrix have been found very close to the existing $S$ = -1, $J^P= 1/2^+$ low lying baryon resonances. The input two-body $t$-matrices for meson-meson and meson-b...
Baryon number transport at LHC energies with the ALICE experiment
Christakoglou, P.(Nikhef, National Institute for Subatomic Physics, Amsterdam, The Netherlands); Botje, M.A.J.; Mischke, A.; Van Leeuwen, M
2009-01-01
Particle yields along with the ratios of particle production in hadronic interactions are important indicators of the collision dynamics. In particular, the detailed analysis of the baryon spectra as well as that of p¯/p and L¯ /L ratios are of great importance since they allow to determine the carrier of the baryon number (BN). In this paper, the expected performance of the ALICE detector setup regarding the baryon spectra, the rapidity and transversemomentum dependence of the ¯ p/p and L¯ /...
Galaxy Evolution by the Incompatibility between Dark Matter and Baryonic Matter
Ding-Yu Chung
2014-01-01
The paper derives the galaxy evolution by the non-interacting (incompatibility) between dark matter and baryonic matter in terms of the short-range separation between dark matter and baryonic matter, so dark matter cannot contact baryonic matter. In the conventional CDM (cold dark matter) model, dark matter and baryonic matter are interactive (compatible), so dark matter can contact baryonic matter. However, the conventional CDM model fails to account for the failure to...
Two-Baryon Correlation Functions in 2-flavour QCD
Francis, Anthony; Rae, Thomas D; Wittig, Hartmut
2013-01-01
We present first results for two-baryon correlation functions, computed using $N_f=2$ flavours of O($a$) improved Wilson quarks, with the aim of explaining potential dibaryon bound states, specifically the H-dibaryon. In particular, we use a GEVP to isolate the groundstate using two-baryon (hyperon-hyperon) correlation functions $\\big(\\langle C_{XY}(t)C_{XY}(0) \\rangle$, where $XY=\\Lambda\\Lambda, \\Sigma\\Sigma, N\\Xi, \\cdots\\big)$, each of which has an overlap with the H-dibaryon. We employ a `blocking' algorithm to handle the large number of contractions, which may easily be extended to N-baryon correlation functions. We also comment on its application to the analysis of single baryon masses ($n$, $\\Lambda$, $\\Xi$, $\\cdots$). This study is performed on an isotropic lattice with $m_\\pi = 460$ MeV, $m_\\pi L = 4.7$ and $a = 0.063$ fm.
Baryon production in $e^{+}e^{-}$-annihilation at PETRA
Bartel, Wulfrin; Dittmann, P; Eichler, R; Felst, R; Haidt, Dieter; Krehbiel, H; Meier, K; Naroska, Beate; O'Neill, L H; Steffen, P; Wenninger, Horst; Zhang, Y; Elsen, E E; Helm, M; Petersen, A; Warming, P; Weber, G; Bethke, Siegfried; Drumm, H; Heintze, J; Heinzelmann, G; Hellenbrand, K H; Heuer, R D; Von Krogh, J; Lennert, P; Kawabata, S; Matsumura, H; Nozaki, T; Olsson, J; Rieseberg, H; Wagner, A; Bell, A; Foster, F; Hughes, G; Wriedt, H; Allison, J; Ball, A H; Bamford, G; Barlow, R; Bowdery, C K; Duerdoth, I P; Hassard, J F; King, B T; Loebinger, F K; MacBeth, A A; McCann, H; Mills, H E; Murphy, P G; Prosper, H B; Stephens, K; Clarke, D; Goddard, M C; Marshall, R; Pearce, G F; Kobayashi, T; Komamiya, S; Koshiba, M; Minowa, M; Nozaki, M; Orito, S; Sato, A; Suda, T; Takeda, H; Totsuka, Y; Watanabe, Y; Yamada, S; Yanagisawa, C
1981-01-01
Data on p and Lambda production by e/sup +/e/sup -/-annihilation at CM energies between 30 and 36 GeV are presented. Indication for an angular anticorrelation in events with baryon-antibaryon pairs is seen.
Glueballs, hermaphrodites and QCD problems for baryon spectroscopy
International Nuclear Information System (INIS)
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)
Strong interaction physics: from quarks to mesons, baryons and nuclei
International Nuclear Information System (INIS)
We summarize some of the important physics issues confronted at the NATO Advanced Research Workshop in Cracow. The topics addressed include modern challenges in understanding baryon and meson structure, hadronic interactions and hadron properties in dense matter. (author)
Non-baryonic dark matter: observational evidence and detection methods
International Nuclear Information System (INIS)
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)
Layers of deformed instantons in holographic baryonic matter
Preis, Florian
2016-01-01
We discuss homogeneous baryonic matter in the decompactified limit of the Sakai-Sugimoto model, improving existing approximations based on flat-space instantons. We allow for an anisotropic deformation of the instantons in the holographic and spatial directions and for a density-dependent distribution of arbitrarily many instanton layers in the bulk. Within our approximation, the baryon onset turns out to be a second-order phase transition, at odds with nature, and there is no transition to quark matter at high densities, at odds with expectations from QCD. This changes when we impose certain constraints on the shape of single instantons, motivated by known features of holographic baryons in the vacuum. Then, a first-order baryon onset and chiral restoration at high density are possible, and at sufficiently large densities two instanton layers are formed dynamically. Our results are a further step towards describing realistic, strongly interacting matter over a large density regime within a single model, desi...
The electroweak axion, dark energy, inflation and baryonic matter
International Nuclear Information System (INIS)
In a previous paper [1], the standard model was generalized to include an electroweak axion which carries baryon plus lepton number, B + L. It was shown that such a model naturally gives the observed value of the dark energy, if the scale of explicit baryon number violation A was chosen to be of the order of the Planck mass. In this paper, we consider the effect of the modulus of the axion field. Such a field must condense in order to generate the standard Goldstone boson associated with the phase of the axion field. This condensation breaks baryon number. We argue that this modulus might be associated with inflation. If an additional B − L violating scalar is introduced with a mass similar to that of the modulus of the axion field, we argue that decays of particles associated with this field might generate an acceptable baryon asymmetry
Identifying the Baryons in a Multiphase Intergalactic Medium
Shull, J Michael
2012-01-01
In this white paper, we summarize current observations of the baryon census at low redshift (Shull, Smith, & Danforth 2012). Measurements of Lya, O-VI, and broad Lya absorbers, together with more careful corrections for metallicity and ionization fraction, can now account for approximately 60% of the baryons in the intergalactic medium (IGM). An additional 5 +/- 3% may reside in the circumgalactic medium (CGM), 7 +/- 2% in galaxies, and 4 +/- 1.5% in clusters. This still leaves a substantial fraction, 29 +/- 13%, unaccounted for. We suggest improvements in measuring the baryons in major components of the IGM and CGM with future Ultraviolet and X-ray spectrographs. These missions could find and map the missing baryons, the fuel for the formation and chemical evolution of galaxies.
Vector Mesons and Baryon Resonances in Nuclear Matter
Post, M.; Mosel, U.
2001-01-01
We calculate the effect of many-body interactions in nuclear matter on the spectral function of $\\rho$ and $\\omega$ meson. In particular, we focus on the role played by baryon resonances in this context.
Quantifying Baryon Stopping in High Energy Nuclear Collisions
Wong, S. M. H.
2000-01-01
We propose a numerical definition for baryon stopping in relativistic heavy ion collisions that is obtainable from final hadron rapidity distributions as well as from bremsstrahlung measurements. Thus a new channel of communication is opened between the two methods.
Baryon deceleration by strong chromofields in ultrarelativistic nuclear collisions
Mishustin, I N; Lyakhov, Konstantin A.; Mishustin, Igor N.
2006-01-01
It is assumed that strong chromofields are generated at early stages of ultrarelativistic heavy-ion collisions which give rise to a collective deceleration of net baryons from colliding nuclei. We have solved classical equations of motion for baryonic slabs under the action of a time-dependent longitudinal chromoelectric field. It is demonstrated that the slab final rapidities are rather sensitive to the strength and decay time of the chromofield as well as to the back reaction of the produced partonic plasma. The net-baryon rapidity loss of about 2 units, found for most central Au-Au collisions at RHIC, can be explained by the action of chromofields with the initial energy density of about 50 GeV/fm^3. Predictions for the baryon stopping at the LHC are made.
Baryon production in e+e--annihilation at PETRA
International Nuclear Information System (INIS)
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.)
Results on baryon antibaryon correlations in e+e--annihilation
International Nuclear Information System (INIS)
The correlations between panti p, Λanti Λ, Ξ-anti Λ and Λ(1520)anti Λ baryons have been measured in e+e- continuum events and in direct Υ decays. The observed correlations exclude the production of point-like diquark-antidiquark pairs as the dominant source of baryons. Information concerning angular momentum compensation follows from the observed Λ(1520)anti Λ correlation. (orig.)
Quark Delocalization, Color Screening Model and Nucleon-Baryon Scattering
Wu, G; Teng, L; Wang, F; Goldman, T; Wu, Guang-han; Ping, Jia-Lun; Teng, Li-jian; Wang, Fan
2000-01-01
We apply the quark delocalization and color screening model to nucleon-baryon scattering. A semi-quantitative fit to N-N, N-Lambda and N-Sigma phase shifts and scattering cross sections is obtained without invoking meson exchange. Quarks delocalize reasonably in all of the different flavor channels to induce effective nucleon-baryon interactions with both a repulsive core and with an intermediate range attraction in the cases expected.
Net baryon number probability distribution near the chiral phase transition
Morita, Kenji; Skokov, Vladimir; Friman, Bengt; Redlich, Krzysztof
2014-01-01
We discuss the properties of the net baryon number probability distribution near the chiral phase transition to explore the effect of critical fluctuations. Our studies are performed within Landau theory, where the coefficients of the polynomial potential are parametrized, so as to reproduce the mean-field (MF), the Z(2) , and the O(4) scaling behaviors of the cumulants of the net baryon number. We show that in the critical region the structure of the probability distribution changes, dependi...
Moduli induced cogenesis of baryon asymmetry and dark matter
Mansi Dhuria; Chandan Hati; Utpal Sarkar
2016-01-01
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 Sup...
Wavelet analysis of baryon acoustic structures in the galaxy distribution
Arnalte-Mur, P.; Labatie, A.; Clerc, N.; Martínez, V. J.; Starck, J.-L.; Lachièze-Rey, M.; Saar, E; Paredes, S.
2012-01-01
Baryon Acoustic Oscillations (BAO) are a feature imprinted in the density field by acoustic waves travelling in the plasma of the early universe. Their fixed scale can be used as a standard ruler to study the geometry of the universe. BAO have been previously detected using correlation functions and power spectra of the galaxy distribution. In this work, we present a new method for the detection of the real-space structures associated with this feature. These baryon acoustic structures are sp...
Doubly heavy spin-1/2 baryon spectrum in QCD
International Nuclear Information System (INIS)
We calculate the mass and residue of the heavy spin-1/2 baryons containing two heavy b or c quarks in the framework of QCD sum rules. We use the most general form of the interpolating current in its symmetric and anti-symmetric forms with respect to the exchange of heavy quarks, to calculate the two-point correlation functions describing the baryons under consideration. A comparison of the obtained results with existing predictions from various approaches is also made.
CDM/baryon isocurvature perturbations in a sneutrino curvaton model
Energy Technology Data Exchange (ETDEWEB)
Harigaya, Keisuke; Kawasaki, Masahiro [Kavli IPMU (WPI), TODIAS, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8583 (Japan); Hayakawa, Taku; Yokoyama, Shuichiro, E-mail: keisuke.harigaya@ipmu.jp, E-mail: taku1215@icrr.u-tokyo.ac.jp, E-mail: kawasaki@icrr.u-tokyo.ac.jp, E-mail: shuichiro@rikkyo.ac.jp [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)
2014-10-01
Matter isocurvature perturbations are strictly constrained from cosmic microwave background observations. We study a sneutrino curvaton model where both cold dark matter (CDM)/baryon isocurvature perturbations are generated. In our model, total matter isocurvature perturbations are reduced since the CDM/baryon isocurvature perturbations compensate for each other. We show that this model can not only avoid the stringent observational constraints but also suppress temperature anisotropies on large scales, which leads to improved agreement with observations.
Chiral String-Soliton Model for the light chiral baryons
Pavlovsky, Oleg
2010-01-01
The Chiral String-Soliton Model is a joining of the two notions about the light chiral baryons: the chiral soliton models (like the Skyrme model) and the Quark-Gluon String models. The ChSS model is based on the Effective Chiral Lagrangian which was proposed in [arXiv:hep-ph/0306216]. We have studied the physical properties of the light chiral baryon within the framework of this ChSS model.
New Paradigm for Baryon and Lepton Number Violation
Perez, Pavel Fileviez
2015-01-01
The possible discovery of proton decay, neutron-antineutron oscillation, neutrinoless 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 generatio...
Investigations of Lepton and Baryon Acceleration in Relativistic Astrophysical Shocks
Double, G P
2004-01-01
Gamma-ray bursts are often the brightest objects in the sky during their short life. Particle acceleration in trans-relativistic shocks, internal to the main blastwave, may explain the early intensity peaks, and particle acceleration in the main blastwave, as it slows from ultrarelativistic speeds to the trans-relativistic range, may explain the afterglow. If the radiation results from energetic leptons, how do leptons become energized? A nonlinear relativistic Monte Carlo model was developed and used to study lepton and baryon acceleration by parallel shocks in the trans-relativistic range. Given the assumptions of this model, if the lepton and baryon number densities are of the same order, leptons will always carry far less energy than baryons. However, if the lepton density exceeds the baryon density by a factor of 300,000, the shock is modified primarily by leptons and energy equipartition between leptons and baryons occurs. The lepton to baryon number density ratio for energy equipartition is independent...
Interaction of vector mesons with baryons and nuclei
International Nuclear Information System (INIS)
After some short introductory remarks on particular issues on the vector mesons in nuclei, in this paper, we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei from a modern perspective using the local hidden gauge formalism for the interaction of vector mesons. We present results for the vector–baryon interaction and in particular for the resonances which appear as composite states, dynamically generated from the interaction of vector mesons with baryons, taking also the mixing of these states with pseudoscalars and baryons into account. We then venture into the charm sector, reporting on hidden charm baryon states around 4400 MeV, generated from the interaction of vector mesons and baryons with charm, which have a strong repercussion on the properties of the J/ΨN interaction. We also address the interaction of K* with nuclei and make suggestions to measure the predicted huge width in the medium by means of transparency ratio. The formalism is extended to study the phenomenon of J/ψ suppression in nuclei via J/ψ photo-production reactions. (author)
Quark-model baryon-baryon interaction and its applications to hypernuclei
International Nuclear Information System (INIS)
The quark-model baryon-baryon interaction fss2, proposed by the Kyoto-Niigata group, is a unified model for the complete baryon octet (B8=N, Λ, Σ and Ξ), which is formulated in a framework of the (3q)-(3q) resonating-group method (RGM) using the spin-flavor SU6 quark-model was functions and effective meson-exchange potentials at the quark level. Model parameters are determined to reproduce properties of the nucleon-nucleon system and the low-energy cross section data for the hyperon-nucleon scattering. Due to the several improvements including the introduction of vector-meson exchange potentials, fss2 has achieved very accurate description of the NN and YN interactions, comparable to various one-boson exchange potentials. We review the essential features of fss2 and our previous model FSS, and their predictions to few-body systems in confrontation with the available experimental data. Some characteristic features of the B8B8 interactions with the higher strangeness, S = -2, -3, -4, predicted by fss2 are discussed. These quark-model interactions are now applied to realistic calculations of few-body systems in a new three-cluster Faddeev formalism which uses two-cluster RGM kernels. As for the few-body systems, we discuss the three-nucleon bound states, the ΛNN-ΣNN system for the hypertriton, the ααΛ system for Λ9Be, and the ΛΛα system for ΛΛ6He. (author)
Study of ψ(3770) decaying to baryon anti-baryon pairs
Xia, Li-Gang
2016-05-01
To study the decays of ψ (3770) going to baryon anti-baryon pairs (B B bar), all available experiments of measuring the cross sections of e+e- → B B bar 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) → B B bar 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) → B B bar .
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¯.
Configuration Mixing of Quark States in Baryons
Saghai, B
2015-01-01
Mixing angles are used to describe the $SU(6)\\otimes O(3)$ symmetry breaking in $\\left[70,~1^-\\right]$ multiplet in the sector of the lowest mass nucleon resonances, which are investigated extensively in constituent quark models for baryon spectroscopy. The transition amplitudes for the meson photoproduction off nucleon can also be expressed in terms of the mixing angles to take into account the configuration mixing. Those amplitudes are derived as a function of the mixing angles between $|N^2P_M{J}^-\\rangle$ and $|N^4P_M{J}^-\\rangle$ states, with $J$=1/2 and 3/2, for the processes $\\gamma p \\to \\eta p,~K^+ \\Lambda,~K^+ \\Sigma^\\circ,~K^\\circ \\Sigma^+$. The present status of our knowledge on the mixing angles between $S_{11}(1535)$ and $S_{11}(1650)$ ($\\theta _{S}$), as well as between $D_{13}(1520)$ and $D_{13} (1700)$ ($\\theta _{D}$) is reported. Since these resonances play very important role in the threshold region for both $\\eta$ and kaon production mechanisms, they are expected to provide crucial tests o...
The Photon-Baryon Governed Universe
Directory of Open Access Journals (Sweden)
Laszlo A. Marosi
2012-01-01
Full Text Available In a previous paper we postulated that the repulsive force responsible for the universal expansion is associated with the excitation of the empty space (quantum vacuum and the excitation energy is represented by the energy of the cosmic microwave background (CMB. In this paper, we show that the concept of the repulsive space expanding photon field (i can successfully be applied to explain the local velocity anomaly of the Milky Way Galaxy as shown by Faber and Burstein (1998 and Tully (1998, (ii offers a convincing explanation of the still disputed question of the cosmological expansion on local and intergalactic scales discussed by Cooperstock et al. (1998, and (iii explains the redshift (RS of the CMB in accordance with the law of energy conservation without the need for dark matter (DM and dark energy (DE. Probably the most remarkable result of this model (abbreviated as photon/baryon: PB model in the following discussion is that the individual voids building up the soup-bubble- (SB- like galaxy distribution are the governing dynamical components of the universal expansion. Further consequence implies that the universe is considerably older than the interpretation of the Hubble constant as expansion velocity suggests.
Soft RPV through the baryon portal
Krnjaic, Gordan; Tsai, Yuhsin
2014-03-01
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.
Structure and reactions of pentaquark baryons
Indian Academy of Sciences (India)
Atsushi Hosaka
2006-04-01
We review the current status of the exotic pentaquark baryons. After a brief look at experiments of both positive and negative results, we discuss theoretical methods to study the structure and reactions for the pentaquarks. First we introduce the quark model and the chiral soliton model, where we discuss the relation of mass spectrum and parity with some emphasis on the role of chiral symmetry. It is always useful to picture the structure of the pentaquarks in terms of quarks. As for other methods, we discuss a model-independent method, and briefly mention the results from the lattice and QCD sum rule. Decay properties are then studied in some detail, which is one of the important properties of +. We investigate the relation between the decay width and the quark structure having certain spin-parity quantum numbers. Through these analyses, we consider as plausible quantum numbers of +, = 3/2-. In the last part of this note, we discuss production reactions of + which provide links between the theoretical models and experimental information. We discuss photoproductions and hadron-induced reactions which are useful to explore the nature of +.
Soft RPV through the baryon portal
International Nuclear Information System (INIS)
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
BASE - The Baryon Antibaryon Symmetry Experiment
Smorra, C; Bojtar, L.; Borchert, M.; Franke, K.A.; Higuchi, T.; Leefer, N.; Nagahama, H.; Matsuda, Y.; Mooser, A.; Niemann, M.; Ospelkaus, C.; Quint, W.; Schneider, G.; Sellner, S.; Tanaka, T.; Van Gorp, S.; Walz, J.; Yamazaki, Y.; Ulmer, S.
2015-01-01
The Baryon Antibaryon Symmetry Experiment (BASE) aims at performing a stringent test of the combined charge parity and time reversal (CPT) symmetry by comparing the magnetic moments of the proton and the antiproton with high precision. Using single particles in a Penning trap, the proton/antiproton $g$-factors, i.e. the magnetic moment in units of the nuclear magneton, are determined by measuring the respective ratio of the spin-precession frequency to the cyclotron frequency. The spin precession frequency is measured by non-destructive detection of spin quantum transitions using the continuous Stern-Gerlach effect, and the cyclotron frequency is determined from the particle's motional eigenfrequencies in the Penning trap using the invariance theorem. By application of the double Penning-trap method we expect that in our measurements a fractional precision of $\\delta g/g$ 10$^{-9}$ can be achieved. The successful application of this method to the antiproton will represent a factor 1000 improvement in the frac...
Baryon-Derived Scaling Relations from CLASH
Czakon, Nicole G.; Donahue, M.; Medezinski, E.; CLASH; Bolocam
2014-01-01
The CLASH observing program has produced a unique data set which allows the accurate calibration of a large set of galaxy cluster masses. The cosmological and astrophysical implications of these measurements extend far beyond HST-only science. To capitalize on the astronomy community’s interest in the CLASH data products, our collaboration has assembled a team of experts across many different observational cluster probes, including: strong lensing, weak lensing, X-ray, and the Sunyaev-Zel’dovich Effect (SZE). By combining weak- and strong-lensing measurements, full cluster profiles can be constrained from the inner tens of kpc out to several Mpc. This has important implications in cross-probe analyses as different observational probes are sensitive to different regions of a cluster’s mass profile. Another goal of the CLASH program is to characterize the level of hydrostatic mass bias in X-ray measurements. This is important as hydrostatic mass estimates are commonly used to calibrate X-ray and SZE cluster studies. In my talk, I will report on the status of several cross-probe scaling relations comparing the CLASH lensing masses and various baryonic cluster mass probes, including: optical richness, X-ray, and SZE observations of the full CLASH cluster catalog. The results of these investigations will be interesting for both large-scale surveys and individual cluster studies, when high quality lensing data is unavailable.
Color Superconductivity at Moderate Baryon Density
Huang, M
2004-01-01
These lectures focus on the two-flavor color superconducting phase at moderate baryon density. In order to simultaneously investigate the chiral phase transition and the color superconducting phase transition, the Nambu-Gorkov formalism is extended to treat the quark-antiquark and diquark condensates on an equal footing. The competition between the chiral condensate and the diquark condensate is analyzed. The cold dense charge neutral two-flavor quark system is investigated in detail. Under the local charge neutrality condition, the ground state of two-flavor quark matter is sensitive to the coupling strength in the diquark channel. When the diquark coupling strength is around the value obtained from the Fierz transformation or from fitting the vacuum bayron mass, the ground state of charge neutral two-flavor quark matter is in a thermal stable gapless 2SC (g2SC) phase. The unusual properties at zero as well as nonzero temperatures and the chromomagnetic properties of the g2SC phase are reviewed. Under the gl...
Quark Interchange Model of Baryon Interactions.
Maslow, Joel Neal
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 we assume 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 (qq) 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)
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
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.
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; Brodzicka, J; Brook, N H; Brown, H; Bursche, A; Busetto, G; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Campana, P; Campora Perez, D; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cenci, R; Charles, M; Charpentier, Ph; Chefdeville, M; Chen, S; Cheung, S-F; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cojocariu, L; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Corvo, M; Counts, I; Couturier, B; Cowan, G A; Craik, D C; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Dalseno, J; David, P; David, P N Y; Davis, A; 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; Dijkstra, H; 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. PMID:25375705
Search for missing baryons through scintillation
International Nuclear Information System (INIS)
Cool molecular hydrogen H2 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 (H2-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 106 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)
Corroboration of the new nuclear force in baryon-baryon scattering
International Nuclear Information System (INIS)
A new nuclear theory based on exponentially decreasing inverse-square-law static nuclear force is considered. It uses theoretical constants, corresponding vector potential and the Dirac-Pauli equation with resulting equivalent Schroedinger potential. More than hundred comparisons with the experiment have been made, 9/10 of them in the area of baryon-baryon scattering. A complete coincidence with the experiment for np-scattering in non-resonance area from 3 MeV to the relativistic limit 50 MeV is obtained. In agreement with the experiment the total cross-sections for nn, pp, λp and σ+p scattering coincide in the range of the graphic curve width. Some shortcomings of the quantum theory of scattering under 20 MeV are pointed out. They require measurements with polarized beams or special calculations taking into account decreasing of the effective scattering cross-section after the spin orientation. Preliminary estimations show that in the range of 1-45 MeV the spin turns at nucleon interaction of 1.3-0.6 fm. For lower energies the inversion take place at larger distances between nucleons. It is concluded that the theory copes successfully with the experiment in the range of applicability of the quantum mechanical methods. (author). 3 figs, 19 refs
Instructive discussion of effective block algorithm for baryon-baryon correlators
Nemura, Hidekatsu
2015-01-01
We describe a fairly specific idea to calculate efficiently a large number of four-point correlation functions, which are primary quantities to study the nuclear force and hyperonic nuclear forces from lattice QCD, for various baryon-baryon (BB) channels. We discuss how the effective block algorithm significantly reduces the number of iterations with considering the four-point correlator of proton-$\\Lambda$ system as a specific example. The effective block algorithm is applied to calculate the 52 channels of four-point correlation functions from nucleon-nucleon to $\\Xi-\\Xi$, in order to study the complete set of isospin symmetric BB interactions. The elapsed times measured on hybrid parallel computation on BlueGene/Q show reasonable performances at various combinations of the number of OpenMP threads and the number of MPI nodes. The numerical results are benchmarked with the results from the unified contraction algorithm for all of computed sites of 52 four-point correlators.
Electromagnetic and axial structures of Baryon ground and resonant states
International Nuclear Information System (INIS)
This thesis is devoted to the investigation of the electroweak structures of baryons. One performs a comprehensive study of the electromagnetic and axial form factors of baryon ground states with flavors 'up', 'down', and 'strange'; regarding baryon resonances the axial charges are investigated. The dynamics for the description of baryons is furnished by the relativistic constituent-quark model, of which three different variants are applied here. The calculations are performed in the framework of relativistic quantum mechanics, where the electromagnetic and axial current operators are constructed along a spectator model in the point-form.While the evaluations of the electroweak form factors are based on an already established formalism, one develops a generally valid formulation for the axial charges. Thereby it becomes possible to calculate these quantities for arbitrary baryon states and completely general interaction models.It turns out that relativistic constituent-quark models can describe in the framework of a Poincare-invariant formalism not only the electromagnetic but also the axial form factors, which are calculated here for the first time for all baryons. Globally, a good agreement with experiment is achieved up to momentum transfers of about 4 GeV/c. With regard to the particularly sensitive quantities, like the electric radii and magnetic moments, the constituent-quark model based on Goldstone-boson exchange yields the best results. In cases, where no experimental data exist, the predictions agree well with results from lattice quantum chromodynamics. The analogue is true for the axial charges of baryon ground and resonant states. Except for some special cases, their values are presented here for the first time comprehensively and consistently. (author)
Heavy-to-light baryonic form factors at large recoil
Mannel, Thomas
2011-01-01
We analyze heavy-to-light baryonic form factors at large recoil and derive the scaling behavior of these form factors in the heavy quark limit. It is shown that only one universal form factor is needed to parameterize Lambda_b to p and Lambda_b to Lambda matrix elements in the large recoil limit of light baryons, while hadronic matrix elements of Lambda_b to Sigma transition vanish in the large energy limit of Sigma baryon due to the space-time parity symmetry. The scaling law of the soft form factor eta(P^{\\prime} \\cdot v), P^{\\prime} and v being the momentum of nucleon and the velocity of Lambda_b baryon, responsible for Lambda_b to p transitions is also derived using the nucleon distribution amplitudes in leading conformal spin. In particular, we verify that this scaling behavior is in full agreement with that from light-cone sum rule approach in the heavy-quark limit. With these form factors, we further investigate the Lambda baryon polarization asymmetry alpha in Lambda_b to Lambda gamma and the forward-...
Spectroscopy of doubly-charmed baryons from lattice QCD
Padmanath, M; Mathur, Nilmani; Peardon, Michael
2015-01-01
We present 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 16^3 X 128, with inverse spacing in temporal direction 1/a_t = 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) 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 analysed 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 expectatio...
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.
Local thermal equilibrium of dense baryonic matter at CBM experiment
International Nuclear Information System (INIS)
The Compressed Baryonic Matter (CBM) experiment at FAIR/GSI laboratory is being designed to perform heavy-ion collisions in fixed target mode at beam energies of 5-45 GeV per nucleon. The major scientific issues addressed in the experiment are the properties of quantum chromodynamics (QCD) at high baryon density and moderate temperature and the order of quark-hadron phase transition at large baryo-chemical potential. However an important question arises whether the dense baryonic matter created in such collisions may achieve a local thermal equilibrium or not. We have investigated the conditions of local thermal equilibrium of baryons and mesons in a small element of volume within the rapidity range |y| <1.0 for central Au+Au collisions at Elab = 10, 20, 30, 40 GeV per nucleon. For this purpose we used the microscopic transport model UrQMD-3.3 in default cascade mode. We calculated the longitudinal-to-transverse pressure anisotropy (PL/PT) and the inverse slope parameter of energy spectra of baryons and mesons inside the cell at different times (t)= 1-15 fm/c measured in center of mass frame. The quantities are averaged over 60 K events at every time step
Decays of J/psi (3100) to baryon final states
International Nuclear Information System (INIS)
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 B8 anti B8 results are in excellent agreement with the psi being an SU(3) singlet as are the results for psi → B10 anti B10. We present the first evidence for the SU(3) violating decays of the type psi → B8 anti B10 + c.c.. Angular distributions for psi → B8 anti B8 are presented and compared with theoretical predictions. Statistics are limited, but the data tends to prefer other than a 1 + Cos2theta distribution
Baryon resonances in a chiral confining model, 1
Umino, Y
1998-01-01
In this two part series a chiral confining model of baryons is used to describe low--lying negative parity resonances $N^*$, $\\Delta^*$, $\\Lambda^*$ and $\\Sigma^*$ in the mean field approximation. A physical baryon in this model consists of interacting valence quarks, mesons and a color and chiral singlet hybrid field coexisting inside a dynamically generated confining region. This first paper presents the quark contribution to the masses and wave functions of negative parity baryons calculated with an effective spin--isospin dependent instanton induced interaction. It does not include meson exchanges between quarks. The three--quark wave functions are used to calculate meson--excited baryon vertex functions to lowest order in meson--quark coupling. When the baryons are on mass--shell each of these vertex functions is a product of a coupling constant and a form factor. As examples, quark contributions to $N^*$ hadronic form factors as well as axial coupling constants are extracted from the vertex functions an...
The Baryon Content of Groups and Clusters of Galaxies
Roussel, H; Blanchard, A
2000-01-01
We have analyzed the properties of a sample of 33 groups and clusters of galaxies and examine the baryon content to check for trends over a decade in temperature down to 1 keV. We examine the relative contribution of galaxies and ICM to baryons in clusters through the gas-to-stellar mass ratio and find that the typical stellar contribution to the baryonic mass is between 5 and 20%. This ratio is found to be roughly independent of temperature. Therefore, we do not confirm the trend of increasing gas-to-stellar mass ratio with increasing temperature as previously claimed. We also determine distribution of the baryon fraction with the density contrast. Virial masses are estimated from two different mass estimators: one based on the isothermal hydrostatic equation (IHE), the other based on scaling law models (SLM). Comparing the two methods, we find that SLM lead to less dispersed baryon fractions over all density contrasts and that the derived mean absolute valuesare significantly lower than IHE mean values. We ...
Structure of charmed baryons studied by pionic decays
Nagahiro, Hideko; Hosaka, Atsushi; Oka, Makoto; Noumi, Hiroyuki
2016-01-01
We investigate the decays of the charmed baryons aiming at the systematic understanding of hadron internal structures based on the quark model by paying attention to heavy quark symmetry. We evaluate the decay widths from the one pion emission for the known excited states, \\Lambda_c^*(2595), \\Lambda_c^*(2625), \\Lambda_c^*(2765), \\Lambda_c^*(2880) and \\Lambda_c^*(2940), as well as for the ground states \\Sigma_c(2455) and \\Sigma_c^*(2520). The decay properties of the lower excited charmed baryons are well explained, and several important predictions for higher excited baryons are given. We find that the axial-vector type coupling of the pion to the light quarks is essential, which is expected from chiral symmetry, to reproduce the decay widths especially of the low lying \\Lambda_c^* baryons. We emphasize the importance of the branching ratios of \\Gamma(\\Sigma_c^*\\pi)/\\Gamma(\\Sigma_c\\pi) for the study of the nature of higher excited \\Lambda_c^* baryons.
Quark-model interactions for complete baryon octet
International Nuclear Information System (INIS)
Baryon-baryon interactions for the complete baryon octet (B8) are investigated in a unified framework of the resonating-group method, in which the spin-flavor SU6 quark-model wave functions are employed. Model parameters are determined to reproduce properties of the nucleon-nucleon system and the low-energy cross section data for the hyperon-nucleon interaction. We then proceed to explore B8B8 interactions in the strangeness S=-2, -3 and -4 sectors. The S-wave phase-shift behavior and total cross sections are systematically understood by 1) the spin-flavor SU6 symmetry, 2) the special role of the pion exchange and 3) the flavor symmetry breaking. (author)
Excited baryons from Bayesian priors and overlap fermions
Energy Technology Data Exchange (ETDEWEB)
F.X. Lee; S.J. Dong; T. Draper; I. Horvath; K.F. Liu; N. Mathur; J.B. Zhang
2003-05-01
Using the constrained-fitting method based on Bayesian priors, we extract the masses of the two lowest states of octet and decouplet baryons with both parities. The calculation is done on quenched 163 x 28 lattices of a = 0.2 fm using an improved gauge action and overlap fermions, with the pion mass as low as 180 MeV. The Roper state N(1440)+ is clearly observed for the first time as the 1st-excited state of the nucleon from the standard interpolating field. Together with other baryons, our preliminary results indicate that the level-ordering of the low-lying baryon states on the lattice is largely consistent with experiment. The realization is helped by cross-overs between the excited + and - states in the region of mp 300 to 400 MeV.
Non-singlet Baryons in Less Supersymmetric Backgrounds
Giataganas, Dimitrios; Picos, Marco; Siampos, Konstadinos
2012-01-01
We analyze the holographic description of non-singlet baryons in various backgrounds with reduced supersymmetries and/or confining. We show that they exist in all AdS_5xY_5 backgrounds with Y_5 an Einstein manifold bearing five form flux, for a number of quarks 5N/8< k< N, independently on the supersymmetries preserved. This result still holds for gamma_i deformations. In the confining Maldacena-Nunez background non-singlet baryons also exist, although in this case the interval for the number of quarks is reduced as compared to the conformal case. We generalize these configurations to include a non-vanishing magnetic flux such that a complementary microscopical description can be given in terms of lower dimensional branes expanding into fuzzy baryons. This description is a first step towards exploring the finite 't Hooft coupling region.
Baryons as relativistic three-quark bound states
Eichmann, Gernot; Williams, Richard; Alkofer, Reinhard; Fischer, Christian S
2016-01-01
We review the spectrum and electromagnetic properties of baryons described as relativistic three-quark bound states within QCD. The composite nature of baryons results in a rich excitation spectrum, whilst leading to highly non-trivial structural properties explored by the coupling to external (electromagnetic and other) currents. Both present many unsolved problems despite decades of experimental and theoretical research. We discuss the progress in these fields from a theoretical perspective, focusing on nonperturbative QCD as encoded in the functional approach via Dyson-Schwinger and Bethe-Salpeter equations. We give a systematic overview as to how results are obtained in this framework and explain technical connections to lattice QCD. We also discuss the mutual relations to the quark model, which still serves as a reference to distinguish 'expected' from 'unexpected' physics. We confront recent results on the spectrum of non-strange and strange baryons, their form factors and the issues of two-photon proce...
Exotic charmed baryon production in ultrarelativistic heavy ion collisions
International Nuclear Information System (INIS)
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 Ωccc, Ξcc, J/Ψ and suppression for Λc, 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
Proposal for the systematic naming of mesons and baryons
International Nuclear Information System (INIS)
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
Measurement of b-Baryons with the CDF II detector
Energy Technology Data Exchange (ETDEWEB)
Heuser, Joachim; /Karlsruhe U., EKP
2007-10-01
We report the observation of new bottom baryon states. The most recent result is the observation of the baryon {Xi}{sub b}{sup -} through the decay {Xi}{sub b}{sup -} {yields} J/{psi}{Xi}{sup -}. The significance of the signal corresponds to 7.7{sigma} and the {Xi}{sub b}{sup -} mass is measured to be 5792.9{+-}2.5(stat.){+-}1.7(syst.) MeV/c{sup 2}. In addition we observe four resonances in the {Lambda}{sub b}{sup 0}{pi}{sup {+-}} spectra, consistent with the bottom baryons {Sigma}{sub b}{sup (*){+-}}. All observations are in agreement with theoretical expectations.
Stability of small-scale baryon perturbations during cosmological recombination
Venumadhav, Tejaswi
2014-01-01
In this paper, we study small-scale fluctuations (baryon pressure sound waves) in the baryon fluid during recombination. In particular, we look at their evolution in the presence of relative velocities between baryons and photons on large scales ($k \\sim 10^{-1} \\ {\\rm Mpc}^{-1}$), which are naturally present during the era of decoupling. Previous work concluded that the fluctuations grow due to an instability of sound waves in a recombining plasma, but that the growth factor is small for typical cosmological models. These analyses model recombination in an inhomogenous universe as a perturbation to the parameters of the homogenous solution. We show that for relevant wavenumbers $k\\gtrsim 10^3\\ {\\rm Mpc}^{-1}$ the dynamics are significantly altered by the transport of both ionizing continuum ($h\
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.
Measurement of the Lifetime of b-baryons
Abreu, P; Adye, T; Adzic, P; Albrecht, Z; Alderweireld, T; Alekseev, G D; Alemany, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Anassontzis, E G; Andersson, P; Andreazza, A; Andringa, S; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbiellini, Guido; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Bizouard, M A; Bloch, D; Blom, H M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Boyko, I; Bozovic, I; Bozzo, M; Branchini, P; Brenke, T; Brenner, R A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cieslik, K; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crépé, S; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Dris, M; Duperrin, A; Durand, J D; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Ellert, M; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Fayot, J; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Ferrer-Ribas, E; Fichet, S; Firestone, A; Flagmeyer, U; Föth, H; Fokitis, E; Fontanelli, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gamblin, S; Gandelman, M; García, C; Gaspar, C; Gaspar, M; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Ghodbane, N; Gil, I; Glege, F; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; González-Caballero, I; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Grahl, J; Graziani, E; Green, C; Grimm, H J; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Haider, S; Hallgren, A; Hamacher, K; Hansen, J; Harris, F J; Hedberg, V; Heising, S; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hughes, G J; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, P E; Joram, C; Juillot, P; Kapusta, F; Karafasoulis, K; Katsanevas, S; Katsoufis, E C; Keränen, R; Kersevan, Borut P; Khomenko, B A; Khovanskii, N N; Kiiskinen, A P; King, B J; Kinvig, A; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Krammer, Manfred; Kriznic, E; Krstic, J; Krumshtein, Z; Kubinec, P; Kurowska, J; Kurvinen, K L; Lamsa, J; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Leinonen, L; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; Lopes, J H; López, J M; López-Fernandez, R; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Mahon, J R; Maio, A; Malek, A; Malmgren, T G M; Malychev, V; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, F; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Meroni, C; Meyer, W T; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Moch, M; Møller, R; Mönig, K; Monge, M R; Moreau, X; Morettini, P; Morton, G A; Müller, U; Münich, K; Mulders, M; Mulet-Marquis, C; Muresan, R; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neufeld, N; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolenko, M; Nomokonov, V P; Normand, Ainsley; Nygren, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Österberg, K; Ouraou, A; Paganoni, M; Paiano, S; Pain, R; Paiva, R; Palacios, J; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Pegoraro, M; Peralta, L; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rakoczy, D; Ratoff, P N; Read, A L; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Royon, C; Ruhlmann-Kleider, V; Ruiz, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sampsonidis, D; Sannino, M; Schneider, H; Schwemling, P; Schwickerath, U; Schyns, M A E; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Sekulin, R L; Shellard, R C; Sheridan, A; Siebel, M; Simard, L C; Simonetto, F; Sissakian, A N; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sopczak, André; Sosnowski, R; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stampfer, D; Stanescu, C; Stanic, S; Stevenson, K; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tegenfeldt, F; Terranova, F; Thomas, J; Timmermans, J; Tinti, N; Tkatchev, L G; Todorova-Nová, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Van Lysebetten, A; Van Vulpen, I B; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Verzi, V; Vilanova, D; Vitale, L; Vlasov, E; Vodopyanov, A S; Vollmer, C F; Voulgaris, G; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G R; Winter, M; Witek, M; Wolf, G; Yi, J; Yushchenko, O P; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G
1999-01-01
The average lifetime of weakly decaying $b$-baryons was studied using 3.6 million $Z^0$ hadronic decays collected by the DELPHI detector at LEP. The measurement of the proper decay time distribution of secondary vertices was used on three complementary samples. The first sample consisted of events with a fully reconstructed $\\Lambda_c^+$ and an opposite charge lepton, or an oppositely charged lepton pair accompanied by a $\\Lambda^0$. The other two samples were more inclusive, where $b$-baryon semileptonic decays were recognized by the presence of either a proton identified by the RICH detector or a $\\Lambda^0$ and a lepton of charge opposite to that of the proton. The combined result was: \\begin{eqnarray*} \\tau(b\\mathrm{-baryon}) = 1.14\\pm0.08 \\; (stat)\\pm0.04 \\; (syst) \\; \\mathrm{ps} \\; . \\end{eqnarray*} It updates and replaces all previous results published by the DELPHI collaboration.
Chiral-symmetry restoration in baryon-rich environments
International Nuclear Information System (INIS)
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)
Quasi-Two-Body Decays of Nonstrange Baryons
Capstick, Simon; Capstick, Simon; Roberts, Winston
1994-01-01
We examine the decays of nonstrange baryons to the final states $\\Delta\\pi$, $N\\rho$, $N\\eta$, $N\\eta^\\prime$, $N\\omega$, $N1/2^+(1440)\\pi$, and $\\Delta3/2^+(1600)\\pi$, in a relativized pair-creation($^3P_0$) model which has been developed in a previous study of the $N\\pi$ decays of the same baryon states. As it is our goal to provide a guide for the possible discovery of new baryon states at CEBAF and elsewhere, we examine the decays of resonances which have already been seen in the partial-wave analyses, along with those of states which are predicted by the quark model but which remain undiscovered. The level of agreement between our calculation and the available widths from the partial-wave analyses is encouraging.
Study of Baryon Spectroscopy Using a New Potential Form
Directory of Open Access Journals (Sweden)
L. I. Abou-Salem
2014-01-01
Full Text Available In the present work, the nonrelativistic quark model is applied to study baryon systems, where the constituent quarks are bound by a suitable hyper central potential. We proposed a new phenomenological form of the interaction potential, digamma-type potential. Using the Jacobi coordinates, the three-body wave equation is solved numerically to calculate the resonance states of the N, Δ, Λ, and Σ baryon systems. The present model contains only two adjustable parameters in addition to the quark masses. Our theoretical calculations are compared to the available experimental data and Cornell potential results. The description of the spectrum shows that the ground states of the considered light and strange baryon spectra are in general well reproduced.
Dark world and baryon asymmetry from a common source
Suematsu, D
2006-01-01
We study generation of baryon number asymmetry and both abundance of dark matter and dark energy on the basis of global symmetry and its associating flat directions in a supersymmetric model. We assume the existence of a model independent axion which is generally expected in the effective theory of superstring. If we consider a combined field of the model independent axion and a pseudo Nambu-Goldstone boson coming from spontaneous breaking of the global symmetry, its potential can be sufficiently flat and then it may present a candidate of the dark energy as a quintessential axion. Both the baryon asymmetry and the dark matter are supposed to be produced nonthermally as the asymmetry of another global charge through the Affleck-Dine mechanism along the relevant flat direction. Its decay to the observable and hidden sectors explains the baryon number asymmetry and the dark matter abundance, respectively.
Mapping chiral symmetry breaking in the excited baryon spectrum
Bicudo, Pedro; Llanes-Estrada, Felipe J; Van Cauteren, Tim
2016-01-01
We study the conjectured "Insensitivity to Chiral Symmetry Breaking" in the highly excited light baryon spectrum. While the experimental spectrum is being measured at JLab and CBELSA/TAPS, this insensitivity remains to be computed theoretically in detail. As the only existing option to have both confinement, highly excited states and chiral symmetry, we adopt the truncated Coulomb gauge formulation of QCD, considering a linearly confining Coulomb term. Adopting a systematic and numerically intensive variational treatment up to 12 harmonic oscillator shells we are able to access several angular and radial excitations. We compute both the excited spectra of $I=1/2$ and $I=3/2$ baryons, up to large spin $J=13/2$, and study in detail the proposed chiral multiplets. While the static-light and light-light spectra clearly show chiral symmetry restoration high in the spectrum, the realization of chiral symmetry is more complicated in the baryon spectrum than earlier expected.
Radial Excitations of low-lying Baryons and the Structure of the $Z^{+}$ Penta-QuarK
Weigel, H
2000-01-01
Within the collective quantization scheme for chiral solitons we discuss states in higher dimensional representations of flavor SU(3) and their relation to radially excited states in the octet. We also consider states which do not have counterparts of the same quantum numbers in the octet or decuplet and cannot be built from three quarks. We focus on the Z^+ penta-quark, presumably the lightest such state, by estimating its mass and decay width.
Quarks and the Poincare group: SU(6) x SU(3) as a classification group for baryons
International Nuclear Information System (INIS)
The description of baryons as a three quark system results in an irreducible unitary representation of the Poincare group. Starting from this description collinear baryon states can be classified within the SU(6) x SU(3) group. (WL)
Double charm baryons and other aspects of hadron spectroscopy
International Nuclear Information System (INIS)
This theory deals mainly with hadron spectroscopy, which is tackled by two different means: non relativistic potential models and adiabatic bag models. The first approach involves the solution of a three-body problem, which is achieved using the formalism of hyperspherical harmonics. A systematic study of the diquark structure in baryons concludes this part of the work. Bag models are reviewed and used to study the possible binding of multiquark states containing five or six quarks. Finally, a systematic study of baryons with double charm is presented
Study of flavor-tagged baryon production in B decay
International Nuclear Information System (INIS)
Using data collected on the Υ(4S) resonance and the nearby continuum by the CLEO-II detector, we have studied combinations of baryons with leptons produced in the process Υ(4S)→B bar B, B→lepton+X, bar B→baryon+X. Our results do not support models which Attribute the bulk of Λc production in bar B decay to the process b→cW-,W-→ bar cs. copyright 1997 The American Physical Society
Baryon asymmetry generation in the electroweak theory. A lattice study
International Nuclear Information System (INIS)
We study the baryon asymmetry generation within the framework of the standard electroweak theory. The assumed first order finite temperature phase transition to the spontaneously broken phase is simulated on the lattice. The Monte Carlo data suggest that the high temperature plasma is populated with gauge-Higgs fluctuations, which produce a change Q in the Chern-Simons number during the transition, thereby creating fermions due to the electroweak anomaly. We provide evidence and arguments in favour of a uniform distribution of Q. This being the case, the baryon asymmetry produced during the phase transition is large enough to explain the asymmetry observed today. (orig.)
On Exotic Systems of Baryons in Chiral Soliton Models
Kopeliovich, Vladimir
2016-01-01
The role of zero mode quantum corrections to the energy of baryonic systems with exotic quantum numbers (strangeness) is discussed. A simple expression for the contribution depending on strange inertia is obtained in the $SU(3)-$collective coordinate quantization approach, and it is shown that this correction stabilizes the systems the stronger the greater their baryon number is. Furthemore, systems are considered which could be interpreted in the quark model language as containing additional $q\\bar q-$pairs. It is argued that a strange skyrmion crystal should have additional binding in comparison with the $SU(2)-$quantized neutron crystal.
Brane-induced Skyrmions : Baryons in Holographic QCD
Nawa, K; Kojo, T; Nawa, Kanabu; Suganuma, Hideo; Kojo, Toru
2006-01-01
We study baryons in holographic QCD with $D4/D8/\\bar{D8}$ multi $D$ brane system. In holographic QCD, the baryon appears as a topologically non-trivial chiral soliton in a four-dimensional effective theory of mesons, which is called `Brane-induced Skyrmion'. We derive and calculate the Euler-Lagrange equation for the hedgehog configuration with chiral profile $F(r)$ and $\\rho$-meson profile $\\tilde G(r)$, and obtain the soliton solution of the holographic QCD.
The effect of antisymmetrization in diquark models of baryons
International Nuclear Information System (INIS)
The effect of antisymmetrization in diquark models of baryons composed of light (u and d) quarks is investigated. The diquark in this study is considered alternately as a point-like and as a composite particle where antisymmetrization is taken into account by means of Generator Coordinate Model operator kernels. The effect on ground state masses and form factors is striking and we are able to conclude that there is a strong dynamical effect due to the presence of antisymmetrization in diquark models of baryon. (author)
Scalar strangeness content of the nucleon and baryon sigma terms
Ren, Xiu-Lei; Geng, Li-Sheng; Meng, Jie
2014-01-01
The scalar strangeness content of the nucleon, characterized by the so-called strangeness-nucleon sigma term, is of fundamental importance in understanding its sea-quark flavor structure. We report a determination of the octet baryon sigma terms via the Feynman-Hellmann theorem by analyzing the latest high-statistics $n_f=2+1$ lattice QCD simulations with covariant baryon chiral perturbation theory up to next-to-next-to-next-to-leading order. In particular, we predict $\\sigma_{\\pi N}=55(1)(4)...
Penta-quark baryon from the QCD Sum Rule
Sugiyama, J; Oka, M; Sugiyama, Jun; Doi, Takumi; Oka, Makoto
2004-01-01
Exotic penta-quark baryon with strangeness +1, \\Theta^+, is studied in the QCD sum rule approach. We derive sum rules for the positive and negative parity baryon states with J=1/2 and I=0. It is found that the standard values of the QCD condensates predict a negative parity \\Theta^+ of mass \\simeq 1.5 GeV, while no positive parity state is found. We stress the roles of chiral-odd condensates in determining the parity and mass of \\Theta^+.
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.
CP violation and the development of cosmological baryon asymmetry
Energy Technology Data Exchange (ETDEWEB)
Senjanovic, G.
1980-01-01
A discussion of the origin of the observed matter-antimatter asymmetry of the universe is presented in the context of the standard cosmological model. Except in the case of the minimal SU(5) theory, it is possible that grand unified theories predict the right order of magnitude for the ratio of baryon to photon number. The question of CP violation is addressed in detail and it is shown that, tied up with symmetry nonrestoration at high temperature, the soft CP violation does remain at T approx. = 10/sup 15/ GeV as to lead to the creation of baryon asymmetry in the very early universe.
CP violation and the development of cosmological baryon asymmetry
International Nuclear Information System (INIS)
A discussion of the origin of the observed matter-antimatter asymmetry of the universe is presented in the context of the standard cosmological model. Except in the case of the minimal SU(5) theory, it is possible that grand unified theories predict the right order of magnitude for the ratio of baryon to photon number. The question of CP violation is addressed in detail and it is shown that, tied up with symmetry nonrestoration at high temperature, the soft CP violation does remain at T approx. = 1015 GeV as to lead to the creation of baryon asymmetry in the very early universe
Diquark correlations in baryon spectroscopy and holographic QCD
International Nuclear Information System (INIS)
We improve upon recent holographic predictions for the nucleon and delta resonance spectra and show how they emerge from a straightforward extension of the ''metric soft wall'' AdS/QCD dual. The resulting mass formula depends on a single adjustable parameter, characterizing confinement-induced IR deformations of the anti-de Sitter metric, and on the fraction of ''good'' (i.e. maximally attractive) diquarks in the baryon's quark model wave function. Despite their remarkable simplicity, the predicted spectra describe the masses of all 48 observed light-quark baryon states and the underlying, linear trajectory structure with unprecedented accuracy
Light Baryon Spectroscopy using the CLAS Spectrometer at Jefferson Laboratory
Crede, Volker
2011-01-01
Baryons are complex systems of confined quarks and gluons and exhibit the characteristic spectra of excited states. The systematics of the baryon excitation spectrum is important to our understanding of the effective degrees of freedom underlying nucleon matter. High-energy electrons and photons are a remarkably clean probe of hadronic matter, providing a microscope for examining the nucleon and the strong nuclear force. Current experimental efforts with the CLAS spectrometer at Jefferson Laboratory utilize highly-polarized frozen-spin targets in combination with polarized photon beams. The status of the recent double-polarization experiments and some preliminary results are discussed in this contribution.
NJL model approach to diquarks and baryons in quark matter
Blaschke, D.; Dubinin, A.; Zablocki, D.
2015-01-01
We describe baryons as quark-diquark bound states at finite temperature and density within the NJL model for chiral symmetry breaking and restoration in quark matter. Based on a generalized Beth-Uhlenbeck approach to mesons and diquarks we present in a first step the thermodynamics of quark-diquark matter which includes the Mott dissociation of diquarks at finite temperature. In a second step we solve the Bethe-Salpeter equation for the baryon as a quark-diquark bound state in quark-diquark m...
Excited Baryon Spectroscopy in the Large $N_c$ Limit
Goity, J L
1996-01-01
The leading in 1/N_c spin-flavor symmetry breaking mass splittings, of order N_c^0, in excited non-strange Baryons are shown to be given, up to two-body operators, by three different effective Hamiltonians: Thomas precession spin-orbit, spin-isospin tensor, and spin-orbit with isospin exchange. Explicit expressions for their matrix elements between low excited Baryons are obtained, and the structure of the mass splittings in large N_c is established to first order of perturbation theory. The problem of extending the large N_c results to the real world with N_c=3 is briefly addressed.
Baryon as impurity for phase transition in string landscape
Kasai, Aya; Nakai, Yuichiro; Ookouchi, Yutaka
2016-06-01
We consider a decay of a false vacuum in flux compactifications of type IIB string theory and study a catalytic effect for a phase transition induced by a new type of impurities. We concentrate on the large N dual of a D5-brane/anti-D5-brane system which has a rich vacuum structure. We show that D3-branes wrapping the 3-cycles can form a baryon bound state with a monopole. We find that these baryon-like objects can make the lifetime of the metastable vacuum shorter.
Robust New Statistic for fitting the Baryon Acoustic Feature
Osumi, Keisuke; Ho, Shirley; Eisenstein, Daniel J.; Vargas-Magaña, Mariana
2015-01-01
We investigate the utility and robustness of a new statistic, $\\omega_{\\ell}\\left(r_{c}\\right)$, for analyzing Baryon Acoustic Oscillations (BAO). We apply $\\omega_{\\ell}\\left(r_{c}\\right)$, introduced in Xu et al. (2010), to mocks and data from the Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) included in the SDSS Data Release Eleven (DR11). We fit the anisotropic clustering using the monopole and quadrupole of the $\\omega_{\\ell}\\left(r_{c}\\right)$ statis...
Baryon Asymmetry, Dark Matter, and Density Perturbation from PBH
Fujita, Tomohiro; Harigaya, Keisuke; Matsuda, Ryo
2014-01-01
We investigate the consistency of a scenario in which the baryon asymmetry, dark matters, as well as the cosmic density perturbation are generated simultaneously through the evaporation of primordial black holes (PBHs). This scenario can explain the coincidence of the dark matter and the baryon density of the universe, and is free from the isocurvature perturbation problem. We show that this scenario predicts the masses of PBHs, right-handed neutrinos and dark matters, the Hubble scale during inflation, the non-gaussianity and the running of the spectral index. We also discuss the testability of the scenario by detecting high frequency gravitational waves from PBHs.
Search for Low Mass Exotic Baryons in One Pion Electroproduction Data Measured at JLAB
Energy Technology Data Exchange (ETDEWEB)
B. Tatischeff; E. Tomasi-Gustafsson
2007-02-05
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 informations on the possible existence of these narrow exotic baryonic resonances.
Hiding of the conserved (anti)baryonic charge into black holes
International Nuclear Information System (INIS)
It is shown that the total number of baryons evaporated by a black hole can differ from that of antibaryons, even if baryonic charge is microscopically conserved. The baryonic asymmetry of the Universe which can be generated by black-hole evaporation in a specific mechanism first proposed by Zeldovich is estimated
Baryomorphosis: Relating the Baryon Asymmetry to the "WIMP Miracle"
McDonald, John
2010-01-01
We present a generic framework, "baryomorphosis", which modifies the baryon asymmetry to be naturally of the order of a typical thermal relic WIMP density. We consider a simple scalar-based model to show how this is possible. This model introduces a sector in which a large initial baryon asymmetry is injected into particles ("annihilons"), phi_{B}, phi_{B, hat}, of mass ~ 100 GeV - 1 TeV. phi_{B}-phi_{B, hat} annihilations convert the initial phi_{B}, phi_{B, hat} asymmetry to a final asymmetry with a thermal relic WIMP-like density. This subsequently decays to a conventional baryon asymmetry whose magnitude is naturally related to the density of thermal relic WIMP dark matter. In this way the two coincidences of baryons and dark matter i.e. why their densities are similar to each other and why they are both similar to a WIMP thermal relic density (the "WIMP miracle"), may be understood. The model can be tested by the production of annihilons at colliders.
The Inner Regions of Disk Galaxies: A Constant Baryonic Fraction?
Directory of Open Access Journals (Sweden)
Federico Lelli
2014-07-01
Full Text Available For disk galaxies (spirals and irregulars, the inner circular-velocity gradient dRV0 (inner steepness of the rotation curve correlates with the central surface brightness ∑*,0 with a slope of ~0.5. This implies that the central dynamical mass density scales almost linearly with the central baryonic density. Here I show that this empirical relation is consistent with a simple model where the central baryonic fraction ƒbar,0 is fixed to 1 (no dark matter and the observed scatter is due to differences in the baryonic mass-to-light ratio Mbar / LR (ranging from 1 to 3 in the R-band and in the characteristic thickness of the central stellar component Δz (ranging from 100 to 500 pc. Models with lower baryonic fractions are possible, although they require some fine-tuning in the values of Mbar/LR and Δz. Regardless of the actual value of ƒbar,0, the fact that different types of galaxies do not show strong variations in ƒbar,0 is surprising, and may represent a challenge for models of galaxy formation in a Λ Cold Dark Matter (ΛCDM cosmology.
Special Classes of Solutions for Linear String Baryon Configuration
Petrov, V. P.; Sharov, G. S.
2001-01-01
For the linear string baryon model with three material points (three quarks) joined sequentially by the relativistic strings, the class of motions admitting linearizable boundary conditions is investigated. These motions may be represented as the Fourier series with eigenfunctions of some boundary-value problem. The two types of rotational motions are found among the mentioned class of solutions.
Pion photo- and electroproduction in relativistic baryon ChPT
Directory of Open Access Journals (Sweden)
Tiator Lothar
2014-06-01
Full Text Available We present a calculation of pion photo- and electroproduction in manifestly Lorentz-invariant baryon chiral perturbation theory up to and including order q4. We fix the low-energy constants by fitting experimental data in all available reaction channels. Our results can be accessed via a web interface, the so-called chiral MAID.
Magnetic Moment Formulas of Baryons Determined by Quantum Numbers
Chang, Yi-Fang
2008-01-01
We propose that the magnetic moment formulas of baryons may be determined by quantum numbers, and obtain three formulas. This is a new type of magnetic moment formula, and agrees better with the experimental values. It is also similar to corresponding mass formulas of hadrons.
Effect of negative energy component on baryon spectra
International Nuclear Information System (INIS)
Employing instantaneous Bethe-Salpeter equation and taking into account the confection of negative energy component of Dirac spinor to one-gluon exchange interaction, the calculation of the Δ, N baryon spectra is carried out. We find that the effect changes the potential parameters significantly, but leaves the global structures of spectrum almost untouched. (author)
Moduli induced cogenesis of baryon asymmetry and dark matter
Dhuria, Mansi; Hati, Chandan; Sarkar, Utpal
2016-05-01
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.
New Observations of beauty baryon decays at LHCb
Vitaly, Andreev
2014-01-01
This report describes the work I have done during my summer student association with the LHCb (Large Hadron Collider Beauty Experiment) collaboration at CERN from 30.06 till 26.09.2014. The project was performed in a team with two other summer students. In this report I concentrate on my contribution to the team work. In addition, one section is dedicated to the management framework called “scrum” which we used to collaborate as a team. The goal of my task was to analyze yet unobserved decays of the beauty Lambda-b-0 baryon. This is interesting since the CP violation still remains unobserved in baryons and beauty baryons are generally not well-known yet. LHCb is the first detector where these heavy baryons can be analyzed in detail. In addition these decays may play an important role in other processes and one can gain new insights into the strong interaction. The analysis presented here was performed on the full 2011-2012 LHC run data and includes several decays which are observed for the first time.
A Baryonic Effect on the Merger Timescale of Galaxy Clusters
Zhang, Congyao; Lu, Youjun
2016-01-01
Accurate estimation of the merger timescale of galaxy clusters is important to understand the cluster merger process and further the formation and evolution of the large-scale structure of the universe. In this paper, we explore a baryonic effect on the merger timescale of galaxy clusters by using hydrodynamical simulations. We find that the baryons play an important role in accelerating the merger process. The merger timescale decreases with increasing the gas fraction of galaxy clusters. For example, the merger timescale is shortened by a factor of up to 3 for merging clusters with gas fractions 0.15, compared with the timescale obtained with zero gas fractions. The baryonic effect is significant for a wide range of merger parameters and especially more significant for nearly head-on mergers and high merging velocities. The baryonic effect on the merger timescale of galaxy clusters is expected to have impacts on the structure formation in the universe, such as the cluster mass function and massive substruct...
Layers of deformed instantons in holographic baryonic matter
Preis, Florian; Schmitt, Andreas
2016-07-01
We discuss homogeneous baryonic matter in the decompactified limit of the Sakai-Sugimoto model, improving existing approximations based on flat-space instantons. We allow for an anisotropic deformation of the instantons in the holographic and spatial directions and for a density-dependent distribution of arbitrarily many instanton layers in the bulk. Within our approximation, the baryon onset turns out to be a second-order phase transition, at odds with nature, and there is no transition to quark matter at high densities, at odds with expectations from QCD. This changes when we impose certain constraints on the shape of single instantons, motivated by known features of holographic baryons in the vacuum. Then, a first-order baryon onset and chiral restoration at high density are possible, and at sufficiently large densities two instanton layers are formed dynamically. Our results are a further step towards describing realistic, strongly interacting matter over a large density regime within a single model, desirable for studies of compact stars.
Relativistic kinetics of baryon production in the big bang
International Nuclear Information System (INIS)
The baryogenesis process in the early hot universe is investigated by means of relativistic kinetic theory. An exact solution to the kinetic equations for supermassive bosons serves to refine previous results: the optimum baryon-production domain is now complemented by bosons of low mass, thus removing the cosmological lower bound that had limited the mass of superheavy bosons. 14 references
Constraining Dark Matter-Baryon Scattering with Linear Cosmology
Dvorkin, Cora; Kamionkowski, Marc
2013-01-01
We derive constraints on elastic scattering between baryons and dark matter using the cosmic microwave background (CMB) data from the Planck satellite and the Lyman-alpha forest data from the Sloan Digital Sky Survey. Elastic scattering allows baryons and dark matter to exchange momentum, affecting the dynamics of linear density perturbations in the early Universe. We derive constraints to scattering cross sections of the form sigma \\propto v^n, allowing for a wide range of velocity dependencies with n between -4 and 2. We improve and correct previous estimates where they exist, including velocity-independent cross section as well as dark matter millicharge and electromagnetic dipole moments. Lyman-alpha forest data dominates the constraints for n>-3, where the improvement over CMB data alone can be several orders of magnitude. Dark matter-baryon scattering cannot affect the halo mass function on mass scales M>10^{12} M_{solar}. Our results imply, model-independently, that a baryon in the halo of a galaxy lik...
Electromagnetic properties of baryons in the constituent quark model
International Nuclear Information System (INIS)
The electromagnetic properties of baryons are investigated in the framework of a relativized quark model. The model includes beyond the usual single quark transition ansatz relativistic effects due to the strong interaction and confinement forces between the quarks. Furthermore the center-of-mass motion of the three-quark system is separated off in a Lorentz-invariant way. All relativistic correction terms are obtained by expanding the corresponding relativistic expressions in powers of the quark velocity. In this way recoil effects on the electromagnetic interaction between the photon and the baryon could be explicitly studied. Using the harmonic oscillator wavefunctions with the configuration mixing from the Isgur-Karl model, the form factors of the nucleon and the electromagnetic transition amplitudes both for longitudinally and transversely polarized photons are calculated for the most important baryon resonances. An extension to baryons involving strange quarks is also considered. Comparisons are made with the results of the nonrelativistic quark model and with some other approaches. (orig.)
Finding a rational nomenclature for mesons and baryons
International Nuclear Information System (INIS)
A history of the Particle Data Group's efforts to find a rational and systematic convention for naming mesons and baryons is given. Several versions of our proposal are reviewed, and name changes which would occur are summarized. Some of the mail we have received is described. We hope to stimulate additional feedback
NJL model approach to diquarks and baryons in quark matter
Blaschke, D; Zablocki, D
2015-01-01
We describe baryons as quark-diquark bound states at finite temperature and density within the NJL model for chiral symmetry breaking and restoration in quark matter. Based on a generalized Beth-Uhlenbeck approach to mesons and diquarks we present in a first step the thermodynamics of quark-diquark matter which includes the Mott dissociation of diquarks at finite temperature. In a second step we solve the Bethe-Salpeter equation for the baryon as a quark-diquark bound state in quark-diquark matter. We obtain a stable, bound baryon even beyond the Mott temperature for diquark dissociation since the phase space occupation effect (Pauli blocking for quarks and Bose enhancement for diquarks) in the Bethe-Salpeter kernel for the nucleon approximately cancel so that the nucleon mass follows the in-medium behaviour of the quark and diquark masses towards chiral restoration. In this situation the baryon is obtained as a "borromean" three-quark state in medium because the two-particle state (diquark) is unbound while ...
Baryon number transport at LHC energies with the ALICE experiment
Christakoglou, P.; Botje, M.A.J.; Mischke, A.; van Leeuwen, M.
2009-01-01
Particle yields along with the ratios of particle production in hadronic interactions are important indicators of the collision dynamics. In particular, the detailed analysis of the baryon spectra as well as that of p¯/p and L¯ /L ratios are of great importance since they allow to determine the carr
Radiative decays of negative parity heavy baryons in QCD
Agamaliev, A K; Savcı, M
2016-01-01
The transition form factors responsible for the radiative $\\Sigma_Q \\to \\Lambda_Q \\gamma$ and $\\Xi_Q^\\prime \\to \\Xi \\gamma$ decays of the negative parity baryons are examined within light cone QCD sum rules. The decay widths of the radiative transitions are calculated using the obtained results of the form factors.
Skewness as a probe of baryon acoustic oscillations
Juszkiewicz, Roman; Hellwing, Wojciech A.; van de Weygaert, Rien
2013-01-01
In this study, we show that the skewness S-3 of the cosmic density field contains a significant and potentially detectable and clean imprint of baryonic acoustic oscillations (BAOs). Although the BAO signal in the skewness has a lower amplitude than second-order measures like the two-point correlati
Universal Neutrino Mass Hierarchy and Cosmological Baryon Number Asymmetry
Xing, Zhi-zhong
2004-01-01
We conjecture that three light Majorana neutrinos and their right-handed counterparts may have a universal geometric mass hierarchy. Incorporating this phenomenological conjecture with the Fritzsch texture of lepton mass matrices in a simple seesaw mechanism, we show that it is possible to simultaneously account for current neutrino oscillation data and the cosmological baryon number asymmetry via leptogenesis.
The search for exotic baryons at the HERMES experiment
International Nuclear Information System (INIS)
One of the interesting questions of Quantum Chromodynamics, the theory that governs the interactions between quarks and gluons, has been whether it is possible to observe hadrons which can not be explained as a combination of only two or three valence quarks. In numerous searches the existence of these exotic hadrons could not be confirmed. Recently, calculations based on the quark soliton model predicted the narrow exotic baryons Θ+ and Ξ--. A narrow resonance identified as the Θ+ was observed by several experiments at the predicted mass of 1540 MeV, but later followed by several dedicated experiments that could not confirm these positive results. At the HERMES experiment a search for the quasi-real photoproduction of the exotic baryon Θ+ on a deuterium target and the subsequent decay through pK0S → pπ+π- revealed a narrow resonance in the pK0S invariant mass distribution at 1528 MeV. In the search for the corresponding antiparticle Ξ-- the result is consistent with zero events. In this thesis we present the search for the exotic baryon Ξ-- on a deuterium target in the data sample used for the observation of the Θ+. An upper limit on the cross section of the exotic baryon Ξ-- is determined. The search for the exotic baryon Θ+ on hydrogen and deuterium targets at the HERMES experiment is extensively discussed. The event mixing method can be used to estimate the distribution of background events. Several difficulties with this method were addressed, but the background description in the case of the exotic baryon Θ+ remains unconvincing. Between the years 2002 and 2005 the HERMES experiment operated with a magnetic holding field around the hydrogen target. A method for the reconstruction of displaced vertices in this field was developed. The data collected during the years 2006 and 2007 offer an integrated luminosity that is several times higher than in previous data sets. After investigating all data sets collected with the HERMES experiment on
The search for exotic baryons at the HERMES experiment
Energy Technology Data Exchange (ETDEWEB)
Deconinck, Wouter
2008-07-15
One of the interesting questions of Quantum Chromodynamics, the theory that governs the interactions between quarks and gluons, has been whether it is possible to observe hadrons which can not be explained as a combination of only two or three valence quarks. In numerous searches the existence of these exotic hadrons could not be confirmed. Recently, calculations based on the quark soliton model predicted the narrow exotic baryons {theta}{sup +} and {xi}{sup --}. A narrow resonance identified as the {theta}{sup +} was observed by several experiments at the predicted mass of 1540 MeV, but later followed by several dedicated experiments that could not confirm these positive results. At the HERMES experiment a search for the quasi-real photoproduction of the exotic baryon {theta}{sup +} on a deuterium target and the subsequent decay through pK{sup 0}{sub S} {yields} p{pi}{sup +}{pi}{sup -} revealed a narrow resonance in the pK{sup 0}{sub S} invariant mass distribution at 1528 MeV. In the search for the corresponding antiparticle {xi}{sup --} the result is consistent with zero events. In this thesis we present the search for the exotic baryon {xi}{sup --} on a deuterium target in the data sample used for the observation of the {theta}{sup +}. An upper limit on the cross section of the exotic baryon {xi}{sup --} is determined. The search for the exotic baryon {theta}{sup +} on hydrogen and deuterium targets at the HERMES experiment is extensively discussed. The event mixing method can be used to estimate the distribution of background events. Several difficulties with this method were addressed, but the background description in the case of the exotic baryon {theta}{sup +} remains unconvincing. Between the years 2002 and 2005 the HERMES experiment operated with a magnetic holding field around the hydrogen target. A method for the reconstruction of displaced vertices in this field was developed. The data collected during the years 2006 and 2007 offer an integrated
Simultaneous Generation of WIMP Miracle-like Densities of Baryons and Dark Matter
McDonald, John
2012-09-01
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.
Generation of WIMP Miracle-like Densities of Baryons and Dark Matter
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.
Pion- and strangeness-baryon $\\sigma$ terms in the extended chiral constituent quark model
An, C. S.; Saghai, B.
2014-01-01
Within an extended chiral constituent quark formalism, we investigate contributions from all possible five-quark components in the octet baryons to the pion-baryon ($\\sigma_{\\pi B}$) and strangeness-baryon ($\\sigma_{s B}$) sigma terms; $B \\equiv N,~\\Lambda,~\\Sigma,~\\Xi$. The probabilities of the quark-antiquark components in the ground-state baryon octet wave functions are calculated by taking the baryons to be admixtures of three- and five-quark components, with the relevant transitions hand...
Intriguing aspects in baryon production at relativistic heavy-ion collider
Indian Academy of Sciences (India)
Huan Zhong Huang
2003-05-01
We review experimental results on baryon production at mid-rapidity in nucleus–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 hadronic expansion before the ﬁnal freeze-out. We highlight recent measurements on the production of protons, lambdas and their anti-particles in terms of these physics issues. We propose a physical mechanism of topological baryon formation through gluon junction hadronization and future measurements, which can test this hypothesis experimentally.
Magnetic Moments of Octet Baryons in Hot and Dense Nuclear Matter
Singh, Harpreet; Dahiya, Harleen
2016-01-01
We have calculated the in-medium magnetic moments of octet baryons in the presence of hot and dense symmetric nuclear matter. Effective magnetic moments of baryons have been derived from medium modified quark masses within chiral SU(3) quark mean field model.Further, for better insight of medium modification of baryonic magnetic moments, we have considered the explicit contributions from the valence as well as sea quark effects. These effects have been successful in giving the description of baryonic magnetic moments in vacuum. The magnetic moments of baryons are found to vary significantly as a function of density of nuclear medium.
Mayer, L; Mayer, Lucio; Moore, Ben
2003-01-01
We show that a global relation between baryonic mass and virial velocity can be constructed from the scale of dwarf galaxies up to that of rich galaxy clusters. The slope of this relation is close to that expected if dark matter halos form in the standard hierarchical cosmogony and capture a universal baryon fraction, once the details of halo structure and the adiabatic contraction of halos due to cooling gas are taken into account. The scatter and deficiency of baryons within low mass halos ($V_{vir} < 50$ km/s) is consistent with the expected suppression of gas accretion by photo-evaporation due to the cosmic UV background at high redshift. The data are not consistent with significant gas removal from strong supernovae winds unless the velocities of galaxies measured from their gas kinematics are significantly lower than the true halo velocities for objects with $V_{vir} < 100$ km/s. Thus models such as $\\Lambda$CDM with a steep mass function of halos may find it difficult to reproduce both the baryon...
Fujiwara, Y; Suzuki, Y
2006-01-01
We calculate Lambda alpha, Sigma alpha and Xi alpha potentials from the nuclear-matter G-matrices of the SU6 quark-model baryon-baryon interaction. The alpha-cluster wave function is assumed to be a simple harmonic-oscillator shell-model wave function. A new method is proposed to derive the direct and knock-on terms of the interaction Born kernel from the hyperon-nucleon G-matrices, with explicit treatments of the nonlocality and the center-of-mass motion between the hyperon and alpha. We find that the SU6 quark-model baryon-baryon interactions, FSS and fss2, yield a reasonable bound-state energy for 5 He Lambda, -3.18 -- -3.62 MeV, in spite of the fact that they give relatively large depths for the Lambda single-particle potentials, 46 -- 48 MeV, in symmetric nuclear matter. An equivalent local potential derived from the Wigner transform of the nonlocal Lambda alpha kernel shows a strong energy dependence for the incident Lambda-particle, indicating the importance of the strangeness-exchange process in the o...
Inside charged black holes. II. Baryons plus dark matter
International Nuclear Information System (INIS)
This is the second of two companion papers on the interior structure of self-similar accreting charged black holes. In the first paper, the black hole was allowed to accrete only a single fluid of charged baryons. In this second paper, the black hole is allowed to accrete in addition a neutral fluid of almost noninteracting dark matter. Relativistic streaming between outgoing baryons and ingoing dark matter leads to mass inflation near the inner horizon. When enough dark matter has been accreted that the center-of-mass frame near the inner horizon is ingoing, then mass inflation ceases and the fluid collapses to a central singularity. A null singularity does not form on the Cauchy horizon. Although the simultaneous presence of ingoing and outgoing fluids near the inner horizon is essential to mass inflation, reducing one or the other of the ingoing dark matter or outgoing baryonic streams to a trace relative to the other stream makes mass inflation more extreme, not the other way around as one might naively have expected. Consequently, if the dark matter has a finite cross section for being absorbed into the baryonic fluid, then the reduction of the amount of ingoing dark matter merely makes inflation more extreme, the interior mass exponentiating more rapidly and to a larger value before mass inflation ceases. However, if the dark matter absorption cross section is effectively infinite at high collision energy, so that the ingoing dark matter stream disappears completely, then the outgoing baryonic fluid can drop through the Cauchy horizon. In all cases, as the baryons and the dark matter voyage to their diverse fates inside the black hole, they only ever see a finite amount of time pass by in the outside universe. Thus the solutions do not depend on what happens in the infinite past or future. We discuss in some detail the physical mechanism that drives mass inflation. Although the gravitational force is inward, inward means opposite direction for ingoing and
Baryon inhomogeneities due to CP violating QCD Z(3) walls
International Nuclear Information System (INIS)
We have investigated the possibility of generating baryon inhomogeneities in the quark-gluon plasma phase in the early universe due to CP violating scattering of quarks and anti-quarks from moving Z(3) domain walls. CP violation, here, is spontaneous in nature, and arises from the non-trivial profile of the background gauge field between different Z(3) vacua. We have calculated the spatial variation of the background gauge field across the Z(3) interface from the profile of the Polyakov loop L(x) for the Z(3) interface and determined the reflection of quarks and anti-quarks using the Dirac equation. Our results have shown that the reflection coefficients of quarks and anti-quarks can differ by a large amount. We have discussed the implications of this for baryon inhomogeneity generation from collapsing large Z(3) walls
Locating the "missing" baryons with extragalactic dispersion measure estimates
McQuinn, Matthew
2013-01-01
Recently, Thornton and coworkers (2013) confirmed a class of millisecond radio bursts likely of extragalactic origin that is well-suited for estimating dispersion measures (DMs). In addition, Lovelace and Richards (2013) showed that DM could be measured even towards non-variable extragalactic synchrotron sources. Motivated by these exciting results, we calculate the probability distribution of DM(z) in different models for how the cosmic baryons are distributed (both analytically and with cosmological simulations). We show that the distribution of DM is quite sensitive to whether the "missing" baryons lie around the virial radius of 10^11-10^13 Msun halos or further out, which is not easily constrained with other observational techniques. The intrinsic contribution to DM from each source could complicate studies of the extragalactic contribution. This difficulty is avoided by stacking based on the impact parameter to foreground galaxies. We show that a stacking analysis using a sample of ~100 DM measurements ...
Observation of the Heavy Baryons Sigma b and Sigma b*.
Aaltonen, T; Abulencia, A; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carillo, S; Carlsmith, D; Carosi, R; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Cilijak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; DaRonco, S; Datta, M; D'Auria, S; Davies, T; Dagenhart, D; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'Orso, M; Delli Paoli, F; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Dörr, C; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraan, A C; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moon, C S; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S
2007-11-16
We report an observation of new bottom baryons produced in pp collisions at the Tevatron. Using 1.1 fb(-1) of data collected by the CDF II detector, we observe four Lambda b 0 pi+/- resonances in the fully reconstructed decay mode Lambda b 0-->Lambda c + pi-, where Lambda c+-->pK* pi+. We interpret these states as the Sigma b(*)+/- baryons and measure the following masses: m Sigma b+=5807.8 -2.2 +2.0(stat.)+/-1.7(syst.) MeV/c2, m Sigma b- =5815.2+/-1.0(stat.)+/-1.7(syst.) MeV/c2, and m(Sigma b*)-m(Sigma b)=21.2-1.9 +2.0(stat.)-0.3+0.4(syst.) MeV/c2. PMID:18233134
Baryon number fluctuations at finite temperature and density
Fu, Wei-jie; Rennecke, Fabian; Schaefer, Bernd-Jochen
2016-01-01
We investigate baryon number fluctuations for finite temperature and density in two-flavor QCD. This is done within a QCD-improved low-energy effective theory in an extension of the approach put forward in [1,2]. In the present work we aim at improving the predictive power of this approach for large temperatures and density, that is, for small collision energies. This is achieved by taking into account the full frequency dependence of the quark dispersion. This ensures the necessary Silver Blaze property of finite density QCD for the first time, which so far was only implemented approximately. Moreover, we show that Polyakov loop fluctuations have a sizeable impact at large temperatures and density. The results for the kurtosis of baryon number fluctuations are compared to previous effective theory results, lattice results and recent experimental data from STAR.
CP violation in multibody decays of beauty baryons
Durieux, Gauthier
2016-01-01
Beauty baryons are being observed in large number in the LHCb detector. The rich kinematics 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 $\\Lambda_b \\to \\Lambda\\,\\varphi \\to p\\,\\pi\\, K^+ K^-$ decay are expected to vanish identically.
Time delayed K sup + N reactions and exotic baryon resonances
Kelkar, N G; Khemchandani, K P
2003-01-01
Evidence and hints, from both the theoretical and experimental sides, of exotic baryon resonances with B = S, have been with us for the last 30 years. The poor status of the general acceptance of these Z* resonances is partly due to the prejudice against penta-quark baryons and partly due to the opinion that a proof of the existence of exotic states must be rigorous. This can refer to the quality and amount of data gathered, and also to the analytical methods applied in the study of these resonances. It then seems mandatory that all possibilities and aspects be exploited. We do that by analysing the time delay in K sup + N scattering, encountering clear signals of the exotic Z* resonances close to the pole values found in partial wave analyses.
Time delayed K+ N reactions and exotic baryon resonances
Kelkar, N G; Khemchandani, K P
2003-01-01
Evidences and hints, both from the theoretical and experimental side, of exotic baryon resonances with B=S, have been with us for the last thirty years. The poor status of the general acceptance of these Z* resonances is partly due to the prejudice against penta-quark baryons and partly due to the opinion that a proof of the existence of exotic states must be rigorous. This can refer to the quality and amount of data gathered, and also to the analytical methods applied in the study of these resonances. It seems then mandatory that all possibilities and aspects be exploited. We do that by analyzing the time delay in K+ N scattering, encountering clear signals of the exotic Z* resonances close to the pole values found in partial wave analyses.
DIOS (Diffuse Intergalactic Oxygen Surveyor): the Dark Baryon Exploring Mission
Tawara, Yuzuru; Ohashi, Takaya; Yamasaki, Noriko; Mitsuda, Kazuhisa
2015-08-01
More than half of the baryons are unidentified in the local Universe, and majority of them are thought to reside along the large-scale structure in the form of Warm-Hot Intergalactic Medium (WHIM). The 3-dimensional structure of WHIM will be probed by observing redshifted oxygen emission lines with high resolution X-ray spectrometers. DIOS (Diffuse Intergalactic Oxygen Surveyor) has been developed aiming for a launch by JAXA’s Epsilon Launch Vehicle around 2020. The payload consists of a 4-reflection X-ray telescope and a TES calorimeter array cooled by mechanical coolers. With a large grasp (area times f.o.v.) over 100 cm2 deg2, DIOS will identify 30-40% of dark baryons and will show us gas dynamics of cosmic plasmas from Earth’s megnetosphere to cluster outskirts. We describe the design and outstanding issues of DIOS.
Two potential quark models for double heavy baryons
International Nuclear Information System (INIS)
Baryons containing two heavy quarks (QQ′ q) are treated in the Born-Oppenheimer approximation. Two non-relativistic potential models are proposed, in which the Schrödinger equation admits a separation of variables in prolate and oblate spheroidal coordinates, respectively. In the first model, the potential is equal to the sum of Coulomb potentials of the two heavy quarks, separated from each other by a distance - R and linear potential of confinement. In the second model the center distance parameter R is assumed to be purely imaginary. In this case, the potential is defined by the two-sheeted mapping with singularities being concentrated on a circle rather than at separate points. Thus, in the first model diquark appears as a segment, and in the second - as a circle. In this paper we calculate the mass spectrum of double heavy baryons in both models, and compare it with previous results
The Small Observed Baryon Asymmetry from a Large Lepton Asymmetry
March-Russell, John David; Riotto, Antonio
1999-01-01
Primordial Big-Bang Nucleosynthesis (BBN) tightly constrains the existence of any additional relativistic degrees of freedom at that epoch. However a large asymmetry in electron neutrino number shifts the chemical equilibrium between the neutron and proton at neutron freeze-out and allows such additional particle species. Moreover, the BBN itself may also prefer such an asymmetry to reconcile predicted element abundances and observations. However, such a large asymmetry appears to be in conflict with the observed small baryon asymmetry if they are in sphaleron mediated equilibrium. In this paper we point out the surprising fact that in the Standard Model, if the asymmetries in the electron number and the muon number are equal (and opposite) and of the size required to reconcile BBN theory with observations, a baryon asymmetry of the Universe of the correct magnitude and sign is automatically generated within a factor of two. This small remaining discrepancy is naturally remedied in the supersymmetric Standard...
Continuum-Mediated Dark Matter-Baryon Scattering
Katz, Andrey; Sajjad, Aqil
2016-01-01
Many models of dark matter scattering with baryons may be treated either as a simple contact interaction or as the exchange of a light mediator particle. We study an alternative, in which a continuum of light mediator states may be exchanged. This could arise, for instance, from coupling to a sector which is approximately conformal at the relevant momentum transfer scale. In the non-relativistic effective theory of dark matter-baryon scattering, which is useful for parametrizing direct detection signals, the effect of such continuum mediators is to multiply the amplitude by a function of the momentum transfer q, which in the simplest case is just a power law. We develop the basic framework and study two examples: the case where the mediator is a scalar operator coupling to the Higgs portal (which turns out to be highly constrained) and the case of an antisymmetric tensor operator ${\\cal O}_{\\mu \
Do Baryons Alter the Halos of Low Surface Brightness Galaxies?
de Naray, Rachel Kuzio
2011-01-01
High-quality observations of dark matter-dominated low surface brightness (LSB) galaxies indicate that, in contrast to the triaxial, centrally-concentrated cuspy halos formed in collisionless simulations of halo assembly, these galaxies reside in round, roughly constant density cored halos. In order to reconcile these data with galaxy formation in the context of LCDM, processes that alter the shape and density structure of the inner halo are required. We compile observational properties of LSB galaxies to evaluate the plausibility that a previously higher baryonic mass content and feedback from star formation can modify the dark matter halos of these galaxies. We also compare the properties of bulgeless disk galaxies formed in recent simulations to the LSB galaxy sample. We find that observational constraints on LSB galaxy star formation histories, structure, and kinematics make it difficult for baryonic physics to sphericalize and decrease the central density of the dark matter halos of LSB galaxies.
Quantifying the effect of baryon physics on weak lensing tomography
Semboloni, Elisabetta; Schaye, Joop; van Daalen, Marcel P; McCarthy, Ian J
2011-01-01
We use matter power spectra from cosmological hydrodynamic simulations to quantify the effect of baryon physics on the weak gravitational lensing shear signal. The simulations consider a number of processes, such as radiative cooling, star formation, supernovae and feedback from active galactic nuclei (AGN). Van Daalen et al. (2011) used the same simulations to show that baryon physics, in particular the strong feedback that is required to solve the overcooling problem, modifies the matter power spectrum on scales relevant for cosmological weak lensing studies. As a result, the use of power spectra from dark matter simulations can lead to significant biases in the inferred cosmological parameters. We show that the typical biases are much larger than the precision with which future missions aim to constrain the dark energy equation of state, w_0. For instance, the simulation with AGN feedback, which reproduces X-ray and optical properties of groups of galaxies, gives rise to a ~40% bias in w_0. We demonstrate ...
Connecting the Baryons: Multiwavelength Data for SKA HI Surveys
Meyer, Martin; Obreschkow, Danail; Driver, Simon; Staveley-Smith, Lister; Zwaan, Martin
2015-01-01
The science achievable with SKA HI surveys will be greatly increased through the combination of HI data with that at other wavelengths. These multiwavelength datasets will enable studies to move beyond an understanding of HI gas in isolation to instead understand HI as an integral part of the highly complex baryonic processes that drive galaxy evolution. As they evolve, galaxies experience a host of environmental and feedback influences, many of which can radically impact their gas content. Important processes include: accretion (hot and cold mode, mergers), depletion (star formation, galactic winds, AGN), phase changes (ionised/atomic/molecular), and environmental effects (ram pressure stripping, tidal effects, strangulation). Governing all of these to various extents is the underlying dark matter distribution. In turn, the result of these processes can significantly alter the baryonic states in which material is finally observed (stellar populations, dust, chemistry) and its morphology (galaxy type, bulge/d...
Two potential quark models for double heavy baryons
Puchkov, A. M.; Kozhedub, A. V.
2016-01-01
Baryons containing two heavy quarks (QQ' q) are treated in the Born-Oppenheimer approximation. Two non-relativistic potential models are proposed, in which the Schrödinger equation admits a separation of variables in prolate and oblate spheroidal coordinates, respectively. In the first model, the potential is equal to the sum of Coulomb potentials of the two heavy quarks, separated from each other by a distance - R and linear potential of confinement. In the second model the center distance parameter R is assumed to be purely imaginary. In this case, the potential is defined by the two-sheeted mapping with singularities being concentrated on a circle rather than at separate points. Thus, in the first model diquark appears as a segment, and in the second - as a circle. In this paper we calculate the mass spectrum of double heavy baryons in both models, and compare it with previous results.
Two potential quark models for double heavy baryons
Energy Technology Data Exchange (ETDEWEB)
Puchkov, A. M.; Kozhedub, A. V. [Saint Petersburg State University (Russian Federation)
2016-01-22
Baryons containing two heavy quarks (QQ{sup ′} q) are treated in the Born-Oppenheimer approximation. Two non-relativistic potential models are proposed, in which the Schrödinger equation admits a separation of variables in prolate and oblate spheroidal coordinates, respectively. In the first model, the potential is equal to the sum of Coulomb potentials of the two heavy quarks, separated from each other by a distance - R and linear potential of confinement. In the second model the center distance parameter R is assumed to be purely imaginary. In this case, the potential is defined by the two-sheeted mapping with singularities being concentrated on a circle rather than at separate points. Thus, in the first model diquark appears as a segment, and in the second - as a circle. In this paper we calculate the mass spectrum of double heavy baryons in both models, and compare it with previous results.
Quark model calculation of charmed baryon production by neutrinos
International Nuclear Information System (INIS)
We study the neutrino production of 25 low-lying charmed baryon resonances in the four flavour quark model. The mass difference of ordinary and charmed quarks is explicitly taken into account. The quark model is used to determine the spectrum of the charmed baryon resonances and the q2 = 0 values of the weak current transition matrix elements. These transition matrix elements are then continued to space-like q2-values by a generalized meson dominance ansatz for a set of suitably chosen invariant form factors. We find that the production of the L = 0 states C0, C1 and C1* is dominant, with the C0 produced most copiously. For L = 1, 2 the Jsup(P) = 3/2- 5/2+ charm states are dominant. We give differential cross sections, total cross sections and energy integrated total cross sections using experimental neutrino fluxes. (orig./BJ)
Strange magnetic moments of octet baryons under SU(3) breaking
Institute of Scientific and Technical Information of China (English)
CAO Lu; WANG Biao; CHEN Hong
2012-01-01
Magnetic moments of octet baryons are parameterized to all orders of the flavor SU(3) breaking with the irreducible tensor technique in order to extract the contribution of each flavor quark to the magnetic moments of the octet baryons.The not-yet measured magnetic moment of Σ0 is predicted to be 0.649 μN.Our parameterized forms for the magnetic moments are explicitly flavor-dependent,and hence each flavor component of the magnetic moments can be evaluated directly via the flavor projection operator.It is fouud that the strange magnetic moment of the nucleon is suppressed due to the small isoscalar anomalous magnetic moment of the nucleon.In particular,the strange magnetic form factor of the nucleon turns out to be positive,(G(s)N) (0) =0.428 μN,which is consistent with recent data.
Baryon and meson phenomenology in the extended Linear Sigma Model
International Nuclear Information System (INIS)
The vacuum phenomenology obtained within the so-called extended Linear Sigma Model (eLSM) is presented. The eLSM Lagrangian is constructed by including from the very beginning vector and axial-vector d.o.f., and by requiring dilatation invariance and chiral symmetry. After a general introduction of the approach, particular attention is devoted to the latest results. In the mesonic sector the strong decays of the scalar and the pseudoscalar glueballs, the weak decays of the tau lepton into vector and axial-vector mesons, and the description of masses and decays of charmed mesons are shown. In the baryonic sector the omega production in proton-proton scattering and the inclusion of baryons with strangeness are described.
Baryon Number Fluctuations in Quasi-particle Model
Zhao, Ameng; Zong, Hongshi
2016-01-01
Baryon number fluctuations are sensitive to the QCD phase transition and 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 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. It can put new constraint on qQGP model and also provide a baseline for the QCD critical point search in heavy-ion collisions at low energies.
Net Baryon Fluctuations from a Crossover Equation of State
Kapusta, J; Young, C
2016-01-01
We have constructed an equation of state which smoothly interpolates between an excluded volume hadron resonance gas at low energy density to a plasma of quarks and gluons at high energy density. This crossover equation of state agrees very well with lattice calculations at both zero and nonzero baryon chemical potential. We use it to compute the variance, skewness, and kurtosis of fluctuations of baryon number, and compare to measurements of proton number fluctuations in central Au-Au collisions as measured by the STAR collaboration in a beam energy scan at the Relativistic Heavy Ion Collider. The crossover equation of state can reproduce the data if the fluctuations are frozen out at temperatures well below than the average chemical freeze-out.
Baryon and lepton number violation in superstring motivated models
International Nuclear Information System (INIS)
We discuss how realistic low energy physics can arise from the E8xE8 superstring. A key role is played by the discrete symmetries which typically arise after compactification. Cosmological problems are avoided because the discrete symmetry we employ is shown to effectively be embedded in a Peccei-Quinn symmetry. The models we present seem to satisfy the known phenomenological constraints. In particular, they possess a harmless axion. Implications for baryon and lepton number violation are discussed. (author)
The baryon number two system in the Chiral Soliton Model
Sarti, Valentina Mantovani; Vento, Vicente; Park, Byung-Yoon
2012-01-01
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 intersoliton interaction on these relative orientations reveals that studies of dense hadronic matter using this model should take into account their implications.
Exact Baryon, Strangeness and Charge Conservation in Hadronic Gas Models
Cleymans, J; Suhonen, E
1997-01-01
Relativistic heavy ion collisions are studied assuming that particles can be described by a hadron gas in thermal and chemical equilibrium. The exact conservation of baryon number, strangeness and charge are explicitly taken into account. For heavy ions the effect arising from the neutron surplus becomes important and leads to a substantial increase in e.g. the $\\pi^-/\\pi^+$ ratio. A method is developed which is very well suited for the study of small systems.
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.
K- Nuclear Potentials Based on Chiral Meson-baryon Amplitudes
Czech Academy of Sciences Publication Activity Database
Mareš, Jiří; Cieplý, Aleš; Gazda, Daniel; Friedman, E.; Gal, A.
Vol. 1441. Melville, New York : American Institute of Physics, 2012, s. 353-357. ISBN 978-0-7354-1036-7. ISSN 0094-243X. [19th Particles and Nuclei International Conference (PANIC11). Cambridge, Massachusetts Institute of Technology (US), 24.07.2012-29.07.2012] R&D Projects: GA MŠk LA08015 Institutional support: RVO:61389005 Keywords : kaon-baryon * interactions * mecis nuclei * masonic atoms Subject RIV: BM - Solid Matter Physics ; Magnetism
The riddle of high-energy baryon number violation
International Nuclear Information System (INIS)
The exciting possibility that anomalous baryon and lepton number violation might be observable at the next generation of supercolliders is suggested by an instanton calculation due to Ringwald and Espinosa. In these Lectures, the current controversial status of these claims is discussed, and several new technologies designed to analyze this question are reviewed. These technologies should contribute more generally to our understanding of weakly- coupled field theories in the nonperturbative regime where both energies and multiplicities are very large. 61 refs., 35 figs
Oscillating neutrons and disappearing baryons: a theoretical overview
International Nuclear Information System (INIS)
Baryon and lepton number are accidental symmetries in the standard SU(3) x SU(2) x (U)1 theory. We discuss the implications of this for neutron oscillations and compare the situation with that in proton decay. To illustrate our arguments we briefly discuss several models where neutron oscillations might be observed with tau/sub n anti n/ approx. 108 - 109 sec. In particular, just to prove a point, we construct a grand unified model with neutron oscillation but no proton decay
Baryon and Lepton Numbers: Life in the Desert
Fileviez Perez, P.
2012-01-01
The simplest theories where we can understand the origin of the baryon and lepton number violating interactions are discussed. We discuss the desert hypothesis in particle physics and the different scenarios where there is no need to assume it. It is shown that the minimal supersymmetric B-L theory predicts lepton number violation at the Large Hadron Collider if supersymmetry is realized at the low scale. We present the BLMSSM where both symmetries, B and L, can be spontaneously broken at the...
Relativistic Study Of The SU(2) Baryon Spectroscopy
International Nuclear Information System (INIS)
Full text: The lower excitation spectrum of nucleon and Δ is calculated in a relativistic chiral quark model [1,2]. Corrections to the baryon mass spectrum from the second order self-energy and exchange diagrams induced by pion and gluon fields are estimated in the field -theoretical framework. Convergent results for the self-energy terms are obtained when including the intermediate quark and anti-quark states with a total momentum up to j=25/2. Relativistic one-meson and color-magnetic one-gluon exchange forces are shown to generate spin 0, 1, 2, etc. operators, which couple the lower and the upper components of the two interacting valent quarks and yield reasonable matrix elements for the lower excitation spectrum of the Nucleon and Delta. The only contribution to the ground state nucleon and Δ comes from the spin 1 operators, which correspond to the exchanged pion or gluon in the l=1 orbit, thus indicating, that the both pion exchange and color-magnetic gluon exchange forces can contribute to the spin of baryons. It is shown also that the contribution of the color-electric component of the gluon fields to the baryon spectrum is enormously large (more than 500 MeV with a value αs =0.65) and one needs to restrict to very small values of the strong coupling constant or to exclude completely the gluon-loop corrections to the baryon spectrum. With this restriction, the calculated spectrum reproduces the main properties of the data, however needs further contribution from the two-pion exchange and instanton induced exchange (for the nucleon sector) forces in consistence with the realistic NN-interaction models. References: 1. E.M. Tursunov J. Physics, G: Nucl. Part. Phys. 31 (2005), 617; 2. E.M. Tursunov arxiv: 08092480 (hep-ph), 2008 ( submitted for publication). (authors)
Observation of the doubly strange b baryon omega(-)(b)
V.M. Abazov; . et al; S.J. de Jong; M. Demarteau; P. Houben; P.J. van den Berg
2008-01-01
We report the observation of the doubly strange b baryon Omega(-)(b) in the decay channel Omega(-)(b) -> J/psi Omega(-), with J/psi -> mu(+)mu(-) and Omega(-) -> Lambda K- -> (p pi(-))K-, in p (p) over bar collisions at root s = 1.96 TeV. Using approximately 1.3 fb(-1) of data collected with the D0
Ground state baryons in the non-relativistic quark model
International Nuclear Information System (INIS)
We analyse the properties of the ground state baryons in the non-relativistic quark model. The three-body problem is solved by means of the hyperspherical expansion. We consider various two-body potentials of power law type and also a three-body linear potential. In displaying the results, we insist on quantities like ratios of splittings which are scale independent and are functions only of the power of the potential and of the ratio of quark masses
Fingerprint of a QCD string in baryon spectra
Energy Technology Data Exchange (ETDEWEB)
Kirchbach, M. [Escuela de Fisica, Universidad Autonoma de Zacatecas, A.P. C-600, 98062 Zacatecas (Mexico)
2001-07-01
Multi-spin valued states of the Rarita-Schwinger type (k/2, k/2) x encircled [(1/2, O) + encircled (0,1/2)] with k = 1, 3, and 5 are found to be realized in the excitation spectra of the light-quark baryons. We conjecture that the above multi-resonance clusters may take their origin from a QCD string described by means of a linear action. (Author)
Magnetic moment of delta baryons with extended sea
International Nuclear Information System (INIS)
In this we have constructed the baryon wave function with suitable quark-gluon Fock states for delta particles. In our study, the sea may be consisting of two gluons or a quark-antiquark pair along with a gluon. In our study, we constrain the sea with spin 0,1,2 and color singlet state for simplicity. We have calculated the magnetic moments for delta particles, after modification in valence quark wave function with due addition of sea component
On relating the genesis of cosmic baryons and dark matter
International Nuclear Information System (INIS)
The similar cosmological energy budgets in visible baryons and dark matter motivate one to consider a common origin for the generation of both. We outline the key features of scenarios that can accommodate a unified framework for the genesis of cosmic matter. In doing so, we provide a brief overview of some of the past and recent developments and discuss the main predictions of a number of models. (paper)
Oscillations of the static meson fields at finite baryon density
International Nuclear Information System (INIS)
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. (author). 19 refs, 6 figs
Baryons in QCD and chiral symmetry breaking parameters
International Nuclear Information System (INIS)
We calculate all baryons in the 56 representation using QCD sum rules. All masses are well predicted and require stringent values of the chiral parameters (0vertical strokeanti uuvertical stroke0) = -(230 +- 15 MeV)3 and ν = (anti ss)/(uu) - 1 = -0.19 +- 0.02. The determination of ν is the most precise to date, the strange quark mass and the quark condensate are also accurately fixed. (orig.)
Flavor Asymmetry of the Sea Quarks in the Baryon Octet
Koretune, Susumu
1998-01-01
We show that the chiral $SU(n)\\otimes SU(n)$ flavor symmetry on the null-plane severely restricts the sea quarks in the baryon octet. It predicts large asymmetry for the light sea quarks $(u,d,s)$, and universality and abundance for the heavy sea quarks. Further it is shown that existence of the heavy sea quarks constrained by the same symmetry reduces the theoretical value of the Ellis-Jaffe sum rule substantially.
Baryon-Rich Quark-Gluon Plasma in Nuclear Collision
Danos, M; Danos, Michael; Rafelski, Johann
2000-01-01
The maximum achievable temperature (energy density) and minimum kinetic energy required for the formation of a baryon-rich quark-gluon plasma formed at central rapidity in small impact parameter nuclear collisions is estimated. A possible mechanism leading to the pile-up of matter is introduced. Plasma formation is expected to appear at about 15 GeV/Nucleon uranium beam energy on a stationary target or 2.7 GeV/Nucleon in colliding beams.
The baryon acoustic oscillation peak: a flexible standard ruler
Roukema, Boudewijn F
2015-01-01
For about a decade, the baryon acoustic oscillation (BAO) peak at about 105 Mpc/h has provided a standard ruler test of the LCDM cosmological model, a member of the Friedmann--Lemaitre--Robertson--Walker (FLRW) family of cosmological models---according to which comoving space is rigid. However, general relativity does not require comoving space to be rigid. During the virialisation epoch, when the most massive structures form by gravitational collapse, it should be expected that comoving spac...
Is the baryon acoustic oscillation peak a cosmological standard ruler?
Roukema, Boudewijn F; Buchert, Thomas; Fujii, Hirokazu; Ostrowski, Jan J.
2015-01-01
In the standard model of cosmology, the Universe is static in comoving coordinates; expansion occurs homogeneously and is represented by a global scale factor. The baryon acoustic oscillation (BAO) peak location is a statistical tracer that represents, in the standard model, a fixed comoving-length standard ruler. Recent gravitational collapse should modify the metric, rendering the effective scale factor, and thus the BAO standard ruler, spatially inhomogeneous. Using the Sloan Digital Sky S...
International Nuclear Information System (INIS)
Because of the near future work of the NA48 experimental group, we have calculated the radiative corrections (RC) to the Dalitz plot of baryon semileptonic decays with angular correlation between polarized emitted baryons and charged leptons. This work covers the two cases, charged and neutral decaying baryons, and it is restricted to the so called three body region of the Dalitz plot. Also it is specialized at the c.m. frame of the emitted baryon. We consider terms up to (α/ product )(q/M1)0, where q is the momentum transfer and M1 is the mass of the decaying baryon, and neglect terms of the order (α/ product )(q/M1)n, n = 1,2,.... The analytical expressions displayed are ready to obtain numerical results, suitable for a model-independent experimental analysis
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 low-dimensional analogue of holographic baryons
International Nuclear Information System (INIS)
Baryons in holographic QCD correspond to topological solitons in the bulk. The most prominent example is the Sakai–Sugimoto model, where the bulk soliton in the five-dimensional spacetime of AdS-type can be approximated by the flat space self-dual Yang–Mills instanton with a small size. Recently, the validity of this approximation has been verified by comparison with the numerical field theory solution. However, multi-solitons and solitons with finite density are currently beyond numerical field theory computations. Various approximations have been applied to investigate these important issues and have led to proposals for finite density configurations that include dyonic salt and baryonic popcorn. Here we introduce and investigate a low-dimensional analogue of the Sakai–Sugimoto model, in which the bulk soliton can be approximated by a flat space sigma model instanton. The bulk theory is a baby Skyrme model in a three-dimensional spacetime with negative curvature. The advantage of the lower-dimensional theory is that numerical simulations of multi-solitons and finite density solutions can be performed and compared with flat space instanton approximations. In particular, analogues of dyonic salt and baryonic popcorn configurations are found and analysed. (paper)
The joint evolution of baryons and dark matter haloes
Pedrosa, Susana E; Scannapieco, Cecilia
2009-01-01
We have studied the dark matter (DM) distribution in a approx 10^12 h^-1 M_sun mass halo extracted from a simulation consistent with the concordance cosmology, where the physics regulating the transformation of gas into stars was allowed to change producing galaxies with different morphologies. The presence of baryons produces the concentration of the DM halo with respect to its corresponding dissipationless run, but we found that this response does not only depend on the amount of baryons gathered in the central region but also on the way they have been assembled. DM and baryons affect each other in a complex way so the formation history of a galaxy plays an important role on its final total mass distribution. The Supernova (SN) feedback regulates the star formation and triggers galactic outflows not only in the central galaxy but also in their satellites. Our results suggest that, as the effects of SN feedback get stronger, satellites get less massive and can even be more easily disrupted by dynamical frict...
Baryon Number Violating Scalar Diquarks at the LHC
Baldes, Iason; Volkas, Raymond R
2011-01-01
Baryon number violating (BNV) processes are heavily constrained by experiments searching for nucleon decay and neutron-antineutron oscillations. If the baryon number violation occurs via the third generation quarks, however, we may be able to avoid the nucleon stability constraints, thus making such BNV interactions accessible at the LHC. In this paper we study a specific class of BNV extensions of the standard model (SM) involving diquark and leptoquark scalars. After an introduction to these models we study one promising extension in detail, being interested in particles with mass of O(TeV). We calculate limits on the masses and couplings from neutron-antineutron oscillations and dineutron decay for couplings to first and third generation quarks. We explore the possible consequences of such a model on the matter-antimatter asymmetry. We shall see that for models which break the global baryon minus lepton number symmetry, (B-L), the most stringent constraints come from the need to preserve a matter-antimatte...
Heavy-Flavor-Conserving Hadronic Weak Decays of Heavy Baryons
Cheng, Hai-Yang; Lin, Guey-Lin; Lin, Yeu-Chung; Yan, Tung-Mow; Yu, Hoi-Lai
2015-01-01
More than two decades ago, we studied heavy-flavor-conserving weak decays of heavy baryons within the framework that incorporates both heavy-quark and chiral symmetries. In view of the first observation of $\\Xi_b^-\\to\\Lambda_b^0\\pi^-$ by LHCb recently, we have reexamined these decays and presented updated predictions. The predicted rates for $\\Xi_b^-\\to\\Lambda_b^0\\pi^-$ in the MIT bag and diquark models are consistent with experiment. The major theoretical uncertainty stems from the evaluation of baryon matrix elements. The branching fraction of $\\Xi_c\\to\\Lambda_c\\pi$ is predicted to be of order $10^{-4}$. It is suppressed relative to $Br(\\Xi_b\\to\\Lambda_b\\pi)$ owing to the shorter lifetime of $\\Xi_c$ relative to $\\Xi_b$ and the destructive nonspectator $W$-exchange contribution. The kinematically accessible weak decays of the sextet heavy baryon $\\Omega_Q$ are $\\Omega_Q\\to\\Xi_Q\\pi$. Due to the absence of the $B_6-B_{\\bar 3}$ transition in the heavy quark limit and the $B_6-B_6$ transition in the model calcul...
Probing the Missing Baryons via kSZ Stacking
Miao, Han; Lin, Wei-Peng; Zhang, Peng-Jie
2016-04-01
Kinetic Sunyaev-Zel'dovich (kSZ) stacking has great potential to become a powerful probe of missing baryons, due to advances in CMB experiments and galaxy surveys. In this paper, we study kSZ stacking in hydrodynamic simulations with different gastrophysics. We quantify the kSZ stacking signal as a function of halo mass, redshift and projection depth. We compare between different simulations to estimate the impact of gastrophysics such as cooling and supernova feedback. Furthermore, we measure the contribution from warm-hot intergalactic medium (WHIM), which is believed to be the reservoir for most, if not all, missing baryons. We find that the WHIM contribution is significant, at the level of ˜ 10%-70%, depending on the angular separation from the stacked halos and other factors. However, contribution from the intracluster medium along the line of sight is in general non-negligible. This complexity requires more detailed and comprehensive analysis on probing the missing baryons with kSZ stacking.
Heavy-flavor-conserving hadronic weak decays of heavy baryons
Cheng, Hai-Yang; Cheung, Chi-Yee; Lin, Guey-Lin; Lin, Yeu-Chung; Yan, Tung-Mow; Yu, Hoi-Lai
2016-03-01
More than two decades ago, we studied heavy-flavor-conserving weak decays of heavy baryons within the framework that incorporates both heavy-quark and chiral symmetries. In view of the first observation of Ξ b - → Λ b 0 π - by LHCb recently, we have reexamined these decays and presented updated predictions. The predicted rates for Ξ b - → Λ b 0 π - in the MIT bag and diquark models are consistent with experiment. The major theoretical uncertainty stems from the evaluation of baryon matrix elements. The branching fraction of Ξ c → Λ c π is predicted to be of order 10-4. It is suppressed relative to {B}({Ξ}_bto {Λ}_bπ ) owing to the shorter lifetime of Ξ c relative to Ξ b and the destructive nonspectator W-exchange contribution. The kinematically accessible weak decays of the sextet heavy baryon Ω Q are Ω Q → Ξ Q π. Due to the absence of the {{B}}_6-{{B}}{_3-} transition in the heavy quark limit and the {{B}}_6-{{B}}_6 transition in the model calculations, Ω Q → Ξ Q π vanish in the heavy quark limit.
Light U(1) gauge boson coupled to baryon number
International Nuclear Information System (INIS)
The authors discuss the phenomenology of a light U(1) gauge boson, γB, 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 γB mass mB is smaller than mz. They show for mΥ B z that the γB coupling αB can be as large as ∼ 0.1 without conflicting with the current experimental constraints. The authors argue that αB ∼ 0.1 is large enough to produce visible collider signatures and that evidence for the γB could be hidden in existing LEP data. They show that there are realistic models in which mixing between the γB 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
Borel sum rules for octet baryons in nuclear medium
International Nuclear Information System (INIS)
Borel sum rules are examined for octet baryons in the nuclear medium. First, it is noticed that in the medium the dispersion relation is realized for the retarded correlation ΠR(ω, q2) in the energy ω. Then, ΠR(ω, q2) is split into even and odd parts of ω in order to apply the Borel transformation. The obtained Borel sum rules differ from those of previous works. The mass shifts of octet baryons are calculated in the leading order of the operator product expansion with linear density approximation for the condensates. It is found that both scalar and vector condensates of the quark field, and +q>, induce attraction to the octet baryons in the medium in contrast to the results of previous works. It is also found that |δMN| > |δMΛ| > |δMΣ| ∼ |δMΞ|. The absolute values, however, turn out to be one order of magnitude larger than those empirically known if a Borel mass of around 1 GeV is used in the present approximation. (author)
Coupled-channel study of baryon resonances with charm
Hofmann, J; Hofmann, Julian; Lutz, Matthias F.M.
2005-01-01
Identifying a zero-range exchange of vector mesons as the driving force for the s-wave scattering of pseudo-scalar mesons off the baryon ground states, a rich spectrum of molecules is formed. We argue that chiral symmetry and large-$N_c$ considerations determine that part of the interaction which generates the spectrum. A bound state with exotic quantum numbers is predicted at mass 2.78 GeV. It couples strongly to the $(\\bar D_s N),(\\bar D \\Lambda ),(\\bar D \\Sigma)$ channels. A further charm minus-one system is predicted at mass 2.84 GeV as a result of $(\\bar D_s \\Lambda), (\\bar D \\Xi)$ interactions. The two so far observed s-wave baryons with charm one are recovered. We argue that the $\\Lambda_c(2880)$ is not a s-wave state. In addition to those states we predict the existence of about ten narrow s-wave baryon states with masses below 3 GeV. A triplet of crypto-exotic states decaying dominantly into channels with an $\\eta'$ is obtained with masses 4.24 GeV and 4.44 GeV.
Aspects Of Baryon Number As A U(1) Symmetry
Pawl, A E
2005-01-01
The non-observation of proton decay strongly suggests that baryon number is a global U(1) (phase rotation) symmetry of the low-energy effective Lagrangian of particle physics. In the first half of this thesis, we explore the surprisingly dramatic consequences of this U(1) symmetry for the Affleck-Dine model of baryogenesis. Affleck-Dine baryogenesis is a popular model for the creation of a matter-antimatter asymmetry which relys on setting a complex scalar field into phase rotation. The phase symmetry of the Lagrangian has all important effect oil the evolution of this scalar field. The baryon number symmetry need not be restricted to a global symmetry. There is growing evidence from string theory, in fact, that global U(1) symmetries must have a gauge origin. In the second half of this thesis, we consider the details of how two different approaches to breaking a, gauged U(1) baryon symmetry would function in a universe with a low Planck scale. A universe with a low Planck scale (Mpl ∼ 103 GeV) has r...
Baryon effects on void statistics in the EAGLE simulation
Paillas, Enrique; Padilla, Nelson; Tissera, Patricia; Helly, John; Schaller, Matthieu
2016-01-01
Cosmic voids are promising tools for cosmological tests due to their sensitivity to dark energy, modified gravity and alternative cosmological scenarios. Most previous studies in the literature of void properties use cosmological N-body simulations of dark matter (DM) particles that ignore the potential effect of baryonic physics. We analyse voids in the mass and subhalo density field in the EAGLE simulations, which follow the evolution of galaxies in a Lambda cold dark matter Universe with state-of-the-art subgrid models for baryonic processes. We study the effect of baryons on void statistics by comparing results with simulations that only follow the evolution of DM, but use the same initial conditions as EAGLE. When using the mass in the simulation, we find that a DM-only simulation produces 24 per cent more voids than a hydrodynamical one, but this difference comes mainly from voids with radii smaller than 5 Mpc. We do not find significant differences in the density profiles between voids in EAGLE and its...
Baryon-Baryon Interactions in the Flavor SU(3) Limit from Full QCD Simulations on the Lattice
Inoue, Takashi; Aoki, Sinya; Doi, Takumi; Hatsuda, Tetsuo; Ikeda, Yoichi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji
2010-01-01
We investigate baryon-baryon (BB) interactions in the 3-flavor full QCD simulations with degenerate quark masses for all flavors. The BB potentials in the orbital S-wave are extracted from the Nambu-Bethe-Salpeter wave functions measured on the lattice. We observe strong flavor-spin dependences of the BB potentials at short distances. In particular, a strong repulsive core exists in the flavor-octet and spin-singlet channel (the 8_s representation), while an attractive core appears in the flavor singlet channel (the 1 representation). We discuss a relation of such flavor-spin dependence with the Pauli exclusion principle in the quark level. Possible existence of an H-dibaryon resonance above the Lambda-Lambda threshold is also discussed.
Fujiwara, Y; Kohno, M; Miyagawa, K
2007-01-01
Previously we calculated the binding energies of the triton and hypertriton, using an SU_6 quark-model interaction derived from a resonating-group method of two baryon clusters. In contrast to the previous calculations employing the energy-dependent interaction kernel, we present new results using a renormalized interaction, which is now energy independent and reserves all the two-baryon data. The new binding energies are slightly smaller than the previous values. In particular the triton binding energy turns out to be 8.14 MeV with a charge-dependence correction of the two-nucleon force, 190 keV, being included. This indicates that about 350 keV is left for the energy which is to be accounted for by three-body forces.
A Census of Baryons in Galaxy Clusters and Groups
Gonzalez, Anthony H.; Zaritsky, Dennis; Zabludoff, Ann I.
2007-09-01
We determine the contribution of stars in galaxies, intracluster stars, and the intracluster medium to the total baryon budget in nearby galaxy clusters and groups. We find that the baryon mass fraction (fb≡Ωb/Ωm) within r500 is constant for systems with M500 between 6×1013 and 1×1015 Msolar. Although fb is lower than the WMAP value, the shortfall is on the order of both the observational systematic uncertainties and the depletion of baryons within r500 that is predicted by simulations. The data therefore provide no compelling evidence for undetected baryonic components, particularly any that would be expected to vary in importance with cluster mass. A unique feature of the current analysis is direct inclusion of the contribution of intracluster light (ICL) in the baryon budget. With the addition of the ICL to the stellar mass in galaxies, the increase in X-ray gas mass fraction with increasing total mass is entirely accounted for by a decrease in the total stellar mass fraction, supporting the argument that the behavior of both the stellar and X-ray gas components is dominated by a decrease in star formation efficiency in more massive environments. Within just the stellar component, the fraction of the total stellar luminosity in the central, giant brightest cluster galaxy (BCG) and ICL (hereafter the BCG+ICL component) decreases as velocity dispersion (σ) increases for systems with 145 km s-1behavior arises from our sample selection, which favored systems with central, giant elliptical galaxies, remains unclear. A more robust result is the identification of low-mass groups with large BCG+ICL components, demonstrating that the creation of ``intracluster'' stars does not require a massive cluster environment. Within r500 and r200, the BCG+ICL contributes on average 40% and 33% of the total stellar light, respectively, for the clusters and groups in our sample. Because these fractions are functions of both enclosed radius and system mass, care should be
Baryon mapping of quark systems: a progress report
International Nuclear Information System (INIS)
A review is made on the development of baryon mapping as a practical tool for achieving a microscopic quark description of nuclei. A new and consistent baryon mapping developed a couple of years ago is presented and a test of this mapping in the context of a three-color extension of the familiar Lipkin model is given. The test confirms that the mapping is able to fully reproduce within its physical substance all the exact states of the model. Equally important, it produces unphysical states fairly high in energy. This is essential for practical applications of the method, in which variational approximations after the mapping invariably mix physical and unphysical states. The test on the three-color Lipkin Model was unable, however, to address two key issues: (1) Will baryon mapping continue to be useful in the presence of the strong spatial three-quark correlations? (2) Will they remain useful in the presence of variational approximations? To address these issues, a series of models due to Koltun and collaborators have been studied. In these models, quarks with color move in one dimension subject to an attractive delta-function interaction. The model is exactly solvable in the infinite-matter limit, both for two and three color. Furthermore, in both cases, the exact solutions indeed exhibit spatial clustering at low densities. The results obtained in a boson mapping of the two-color delta model combined with a Hartree Bose variational analysis are presented. Analogous results for the tree-color model, involving a baryon mapping followed by a Hartree-Fock treatment are also presented. Both analyses are unable to treat correctly effects of the cluster-cluster interactions, even at the lowest order at which they contribute. An improved analysis of the two-color model is discussed, in which short-range correlations between bosons (quark pairs) are treated in Bruechner theory. This analysis gives perfect agreement with the exact results, through the lowest order in
Hydrodynamics of a quark droplet II: Implications of a non-zero baryon chemical potential
Energy Technology Data Exchange (ETDEWEB)
Bjerrum-Bohr, Johan J. [Frankfurt Institute for Advanced Studies (FIAS), Goethe-University, Ruth-Moufang Str. 1, 60438 Frankfurt am Main (Germany); Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 København Ø (Denmark); Mishustin, Igor N. [Frankfurt Institute for Advanced Studies (FIAS), Goethe-University, Ruth-Moufang Str. 1, 60438 Frankfurt am Main (Germany); Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 København Ø (Denmark); Kurchatov Institute, Russian Research Center, Akademika Kurchatova Sqr., Moscow 123182 (Russian Federation); Døssing, Thomas [Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 København Ø (Denmark)
2014-03-01
We present an extended version of the dynamical model for a multi-quark droplet evolution described in our proceeding paper. The model includes collective expansion of the droplet, effects of the vacuum pressure and surface tension, and now a non-zero baryon number. The hadron emission from the droplet is described following Weisskopf's statistical model. We consider evolutions of droplets with different initial temperatures and net baryon number. It is found that the introduction of a non-zero net baryon number does not change the lifetime of the droplets significantly. Only when we consider an initially very baryon-rich, low-temperature droplets is the lifetime is decreased significantly. We have, furthermore, found a convergence of both baryon chemical potential and temperature toward the values μ{sub B}≈450 MeV and T≈150 MeV. This convergence is linked to the competing emission of baryons versus mesons.
Hydrodynamics of a quark droplet II: Implications of a non-zero baryon chemical potential
Bjerrum-Bohr, Johan J; Døssing, Thomas
2013-01-01
We present an extended version of the dynamical model for a multi-quark droplet evolution described in our proceeding paper. The model includes collective expansion of the droplet, effects of the vacuum pressure and surface tension, and now a non-zero baryon number. The hadron emission from the droplet is described following Weisskopf's statistical model. We consider evolutions of droplets with different initial temperatures and net baryon number. It is found that the introduction of a non-zero net baryon number does not change the lifetime of the droplets significantly. Only when we consider an initially very baryon-rich, low-temperature droplets is the lifetime is decreased significantly. We have, furthermore, found a convergence of both baryon chemical potential and temperature toward the values $T \\approx 150$ MeV and $\\mu_{\\rm B} \\approx$ 450 MeV. This convergence seems to be linked to the competing emission of baryons versus mesons.
Extended-soft-core Baryon-Baryon ESC08 model III. S=-2 Hyperon-hyperon/nucleon Interaction
Nagels, M M; Yamamoto, Y
2015-01-01
This paper presents the Extended-Soft-Core (ESC) potentials ESC08c for baryon-baryon channels with total strangeness S=-2. The potential models for S=-2 are based on SU(3) extensions of ESC potential models for the S=0 and S=-1 sectors, which are fitted to experimental data. Flavor SU(3)-symmetry is broken only kinematically by the masses of the baryons and the mesons. For the S=-2 channels no experimental scattering data exist, and also the information from hypernuclei is rather limited. Nevertheless, in the fit to the S=0 and S=-1 sectors information from the so called NAGARA event and the $\\Xi$-well-depth has been used as constraints to determine the free parameters in the simultaneous fit of the $NN \\oplus YN \\oplus YY$ data. Therefore, the potentials for the S=-2 sector are determined mainly by the NN-, YN-data, and SU(3)-symmetry.Various properties of the potentials are illustrated by giving results for scattering lengths, effective ranges, bound states, elastic and inelastic phase parameters, and total...
Towards Skyrmion Stars: Large Baryon Configurations in the Einstein-Skyrme Model
Piette, B M A G
2007-01-01
We investigate the large baryon number sector of the Einstein-Skyrme model as a possible model for baryon stars. Gravitating hedgehog skyrmions have been investigated previously and the existence of stable solitonic stars excluded due to energy considerations. However, in this paper we demonstrate that by generating gravitating skyrmions using rational maps, we can achieve multi-baryon bound states whilst recovering spherical symmetry in the limit where B becomes large.
Skyrmion Black Hole Hair: Conservation of Baryon Number by Black Holes and Observable Manifestations
Dvali, Gia; Gußmann, Alexander
2016-01-01
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/sky...
Strange baryon production in Pb-Pb collisions at 158 A GeV/c
Fini, R A; Beutsch, W; Bloodworth, Ian J; Caliandro, R; Carrer, N; Di Bari, D; Di Liberto, S; Elia, D; Evans, D; Fanebust, K; Fayazzadeh, F; Ftácnik, J; Ghidini, B; Grella, G; Gulino, G; Helstrup, H; Henriquez, M; Holme, A K; Huss, D; Jacholkowski, A; Jones, G T; Kinson, J B; Knudson, K; Králik, I; Lenti, V; Lietava, R; Loconsole, R A; Løvhøiden, G; Manzari, V; Mazzoni, M A; Meddi, F; Michalon, A; Michalon-Mentzer, M E; Morando, M; Norman, P I; Pastircák, B; Quercigh, Emanuele; Röhrich, D; Romano, G; Safarík, K; Sándor, L; Segato, G F; Staroba, P; Thompson, M; Torrieri, G D; Urbán, J; Vik, T; Villalobos Baillie, O; Virgili, T; Votruba, M F; Závada, P
2001-01-01
The experiment WA97 is dedicated to the study of strange baryon production in Pb-Pb interactions at SPS energy. Results on the production of strange and multistrange baryons at midrapidity in Pb- Pb at 158 A GeV c/sup -1/ are reported and compared with those from p-Pb and p-Be reactions at the same energy. The evidence for deconfinement emerging from the observed pattern of strange baryon production is discussed. (13 refs).
The Thermal Sunyaev Zel'dovich effect : a powerful probe for missing baryons
Zhang, P. J.; Pen, U. L.
2001-01-01
About 90% of baryons in the universe have thus far escaped direct observation. This is known as the {\\it missing baryon problem}. The Sunyaev Zel'dovich effect (SZ effect) has the potential to directly measure the state of the majority of these missing baryons. The next generation CMB experiments such as AMIBA will provide an unbiased sample of the intergalactic medium through the SZ effect. The existing and upcoming simulations and analytical studies provide a quantitative understanding of t...
What can we learn from unpolarized and polarized electroproduction of fast baryons
International Nuclear Information System (INIS)
Two applications of semi-inclusive electroproduction of fast baryons are presented: (i) The steepness of the baryon spectrum at medium rapidity can give information about the general mechanisms of baryon production in soft and hard processes. (ii) With a polarized target and a detector which analyses the polarization of final Λ's, the aptitude of quarks to carry transverse polarization can be tested for the first time
International Nuclear Information System (INIS)
We investigate the kaon production at finite temperature and baryon density by means of an effective relativistic mean-field model with the inclusion of the full octet of baryons. Kaons are considered taking into account of an effective chemical potential depending on the self-consistent interaction between baryons. The obtained results are compared with a minimal coupling scheme, calculated for different values of the anti-kaon optical potential.
Light Quark Spin-Flavor Symmetry for Baryons Containing a Heavy Quark in Large N QCD
Jenkins, E
1993-01-01
The couplings and interactions of baryons containing a heavy quark are related by light quark spin-flavor symmetry in the large $N$ limit. The single pion coupling constant which determines all heavy quark baryon-pion couplings is equal to the pion coupling constant for light quark baryons. Light quark symmetry relations amongst the baryon couplings are violated at order $1/N^2$. Heavy quark spin-flavor symmetry is used in conjunction with large $N$ light quark spin-flavor symmetry to determi...
Strong coupling expansion in lattice QCD at finite temperature and finite baryon density
International Nuclear Information System (INIS)
Using strong coupling expansion in lattice QCD we study analytically the restoration of chiral symmetry in the theory with finite temperature and finite baryon number density and make predictions regarding the order of the phase transition. The inclusion of baryons does not change the phase picture when μ=0, and in full QCD (with mesons and baryons) there is a chiral phase transition of the second order, discovered earlier in QCD without baryons. We have found a first order chiral phase transition at μ=μc and at any low temperature. (author). 19 refs, 3 figs
The Thermal Sunyaev Zel'dovich effect a powerful probe for missing baryons
Zhang, P J
2001-01-01
About 90% of baryons in the universe have thus far escaped direct observation. This is known as the {\\it missing baryon problem}. The Sunyaev Zel'dovich effect (SZ effect) has the potential to directly measure the state of the majority of these missing baryons. The next generation CMB experiments such as AMIBA will provide an unbiased sample of the intergalactic medium through the SZ effect. The existing and upcoming simulations and analytical studies provide a quantitative understanding of the SZ effect. All these make the SZ effect a powerful baryon probe. We present an overview of this probe from both phenomelogical and theoretical aspects.
Babu, K. S.; Mohapatra, Rabindra N.
2016-01-01
We point out that if the baryon number violating neutron-antineutron oscillation is discovered, it would impose strong limits on the departure from Einstein's equivalence principle at a level of one part in $10^{19}$. If this departure owes its origin to the existence of long-range forces coupled to baryon number $B$ (or $B-L$), it would imply very stringent constraints on the strength of gauge bosons coupling to baryon number current. For instance, if the force mediating baryon number has st...
Search for popcorn mesons in events with two charmed baryons
Hartfiel, Brandon
The physics of this dissertation is divided into two parts. The first part measures the Λc → pi kp continuum momentum spectrum at a center of mass energy of 10.54 GeV/c, which is just below the Υ(4s) resonance. The data sample consists of 15,400 Λc baryons from 9.46 fb-1 of integrated luminosity collected with the BaBar detector at the PEP-II asymmetric B factory at the Stanford Linear Accelerator Center. 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 Λc → K0p mode, and look for events with a Λc+ and a Λ c- 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-1. We find 619 events after background subtraction. After a subtraction of 1.06+/-.09 charged pions coming from decays of known resonances to Λc + npi, we are left with 2.63+/-.21 additional charged pious in each of these events. This is significantly higher than the .5 popcorn mesons per bayon 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.
Brane-induced Skyrmion on S3: Baryonic matter in holographic QCD
International Nuclear Information System (INIS)
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 MKK∼1 GeV, to keep the holographic duality with QCD. We describe the baryonic matter in large Nc as single brane-induced Skyrmion on the three-dimensional closed manifold S3 with finite radius R. The interactions between baryons are simulated by the curvature of the closed manifold S3, and the decrease of the size of S3 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 S3 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 MKK.
Dark matter growth and baryon bias in an accelerating universe
Lee, Seokcheon
2009-01-01
We investigate the exact analytic solutions for the growths of the dark matter and the baryon in sub-horizon scale. The growth of the dark matter $\\delta_{\\DM}$ is related to that of the halos. Thus, the exact solution for the growth of the dark matter is important to obtain the proper properties of dark matter halos. However, the dark energy model dependence of $\\delta_{\\DM}$ is confused with the $\\delta_{\\DM}$ dependence on $\\Omega_{m}^{0}$. Thus, the careful investigation is necessary for ...
A low-dimensional analogue of holographic baryons
Bolognesi, S; Sutcliffe, P.M.
2013-01-01
Baryons in holographic QCD correspond to topological solitons in the bulk. The most prominent example is the Sakai–Sugimoto model, where the bulk soliton in the five-dimensional spacetime of AdS-type can be approximated by the flat space self-dual Yang–Mills instanton with a small size. Recently, the validity of this approximation has been verified by comparison with the numerical field theory solution. However, multi-solitons and solitons with finite density are currently beyond numerical fi...
Baryon resonances without quarks: A chiral soliton perspective
Energy Technology Data Exchange (ETDEWEB)
Karliner, M.
1987-03-01
In many processes involving low momentum transfer it is fruitful to regard the nucleon as a soliton or ''monopole-like'' configuration of the pion field. In particular, within this framework it is possible to obtain detailed predictions for pion-nucleon scattering amplitudes and for properties of baryon resonances. One can also derive model-independent linear relations between scattering amplitudes, such as ..pi..N and anti KN. A short survey of some recent results is given, including comparison with experimental data.
Observation and Mass Measurement of the Baryon $\\Xi^-_b$
Aaltonen, T; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P H; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bölla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, Yu; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carrillo, S; Carlsmith, D; Carosi, R; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Cilijak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca-Almenar, C; Cuevas-Maestro, J; Culbertson, R; Cully, J C; Da Ronco, S; Datta, M; D'Auria, S; Davies, T; Dagenhart, D; De Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'Orso, Mauro; Delli Paoli, F; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Dorr, C; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernández, J P; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; García, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Golossanov, A; Gómez, G; Gómez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Group, R C; Grundler, U; Guimarães da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Höcker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraan, A C; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lu, R S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Mäki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martinez-Ballarin, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtälä, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moon, C S; Moore, R; Morello, M; Movilla-Fernández, P A; Mülmenstädt, J; Mukherjee, A; Müller, T; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Österberg, K; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, Aldo L; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P B; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Salto, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shalhout, S Z; Shapiro, M D; Shears, T G; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakian, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Söderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; Saint-Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuno, S; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; Van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veramendi, G; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Vollrath, I; Volobuev, I P; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zhou, J; Zucchelli, S
2007-01-01
We report the observation and measurement of the mass of the bottom, strange baryon $\\Xi^-_b$ through the decay chain $\\Xi^-_b \\to J/\\psi \\Xi^-$, where $J/\\psi \\to \\mu^+ \\mu^-$, $\\Xi^- \\to \\Lambda \\pi^-$, and $\\Lambda \\to p \\pi^-$. Evidence for observation is based on a signal whose probability of arising from the estimated background is $6.6 \\times 10^{-15}$, or 7.7 Gaussian standard deviations. The $\\Xi^-_b$ mass is measured to be $5792.9\\pm 2.5$ (stat.) $\\pm 1.7$ (syst.) MeV/$c^2$.
Baryons in 2+1 flavour domain wall QCD
Antonio, D. J.; Bowler, K. C.; Boyle, P. A.; Clark, M A; Joó, B.; Kennedy, A. D.; Kenway, R. D.; Maynard, C. M.; Tweedie, R. J.; Yamaguchi, A; RBC; collaborations, UKQCD
2005-01-01
We present results for some of the light baryon masses and their excited states in 2+1 flavour domain wall QCD. We considered several lattice spacings, with the DBW2 and Iwasaki gauge actions and different sea quark masses on a volume of $16^3\\times32$ and a fifth dimension of size 8. All data were generated on the QCDOC machines. Despite large residual massses and a limited number of sea quark mass values with which to perform chiral extrapolations, our results are in reasonable agreement wi...
Chiral dynamics of baryons in the perturbative chiral quark model
Energy Technology Data Exchange (ETDEWEB)
Pumsa-ard, K.
2006-07-01
In this work we develop and apply variants of a perturbative chiral quark model (PCQM) to the study of baryonic properties dominantly in the low-energy region. In a first step we consider a noncovariant form of the PCQM, where confinement is modelled by a static, effective potential and chiral corrections are treated to second order, in line with similar chiral quark models. We apply the PCQM to the study of the electromagnetic form factors of the baryon octet. We focus in particular on the low-energy observables such as the magnetic moments, the charge and magnetic radii. In addition, the electromagnetic N-delta transition is also studied in the framework of the PCQM. In the chiral loop calculations we consider a quark propagator, which is restricted to the quark ground state, or in hadronic language to nucleon and delta intermediate states, for simplicity. We furthermore include the low-lying excited states to the quark propagator. In particular, the charge radius of the neutron and the transverse helicity amplitudes of the N-delta transition are considerably improved by this additional effect. In a next step we develop a manifestly Lorentz covariant version of the PCQM, where in addition higher order chiral corrections are included. The full chiral quark Lagrangian is motivated by and in analogy to the one of Chiral Perturbation Theory (ChPT). This Lagrangian contains a set of low energy constants (LECs), which are parameters encoding short distance effects and heavy degrees of freedom. We evaluate the chiral Lagrangian to order O(p{sup 4}) and to one loop to generate the dressing of the bare quark operators by pseudoscalar mesons. In addition we include the vector meson degrees of freedom in our study. Projection of the dressed quark operators on the baryonic level serves to calculate the relevant matrix elements. In a first application of this scheme, we resort to a parameterization of the valence quark form factors in the electromagnetic sector. Constraints
Discrete Symmetry Transformation of Baryon- and Lepton-Nonconserving Processes
Jafari, Ehsan
2016-01-01
In this paper we consider discrete symmetry (C, P, T and CP) transformations of baryon- and lepton-nonconserving processes. According to our calculation it is not possible to definite exact discrete symmetry transformation for any operator which breaks $B-L$ and changes the number of fundamental fermions between initial and final states. In order to count the net change of fundamental fermions between initial and final states, $F$ number has been introduced. On the other hand from theoretical point of view we are not able to label operators which break $B-L$ and violate F number as $-even$ or $-odd$ under the effect of discrete symmetries.
Measurement of the mass of the $\\Lambda_{b}$ baryon
Buskulic, Damir; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Moneta, L; Oest, T; Palla, Fabrizio; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Wildish, T; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; 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; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; 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; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; 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1996-01-01
In a data sample of four million hadronic \\Z\\ decays collected with the ALEPH detector at LEP, four $\\Lambda_b$ baryon candidates are exclusively reconstructed in the $\\Lambda_b \\rightarrow \\Lambda_c^+ \\pi^-$ channel, with the $\\Lambda_c^+$ decaying into $pK^-\\pi^+$, $p\\bar{K^0}$, or $\\Lambda\\pi^+\\pi^+\\pi^-$. The probability of the observed signal to be due to a background fluctuation is estimated to be $4.2 \\times 10^{-4}$. The mass of the $\\Lambda_b$ is measured to be $5614 \\pm 21 \\, (stat.) \\pm 4 \\, (syst.)~\\mevcc$. %$5614\\pm 21\\,(stat.) \\pm 4\\,(syst.) \\mevcc$.
Mixing angle of doubly heavy baryons in QCD
International Nuclear Information System (INIS)
We calculate the mixing angles between the spin-1/2, Ξbc-Ξbc′ and Ωbc-Ωbc′ states of doubly heavy baryons within the QCD sum rules method. It is found that the mixing angles are large and have the values φΞbc=16°±5° and φΩbc=18°±6°, respectively. The mixing angles are slightly smaller compared to the predictions of the non-relativistic quark model, φΞbc=25.5° and φΩbc=25.9°.
QCD sum rules and properties of baryons in nuclei
International Nuclear Information System (INIS)
The use of medium-energy experiments to constrain in-medium four-quark condensates, whose uncertainty is currently the most important problem inhibiting the use of QCD sum rules to study hadrons in nuclear matter, is discussed. A value for a particular linear combination of these condensates is extracted using results of an Isobar-Doorway model analysis of pion-nucleus scattering data and a QCD sum rule analysis of the mass of the Δ(1232) in nuclei. Extending the analysis to include higher-lying baryon resonances is possible with data from modem facilities
Light-cone sum rule approach for Baryon form factors
Offen, Nils
2016-01-01
We present the state-of-the-art of the light-cone sum rule approach to Baryon form factors. The essence of this approach is that soft Feynman contributions are calculated in terms of small transverse distance quantities using dispersion relations and duality. The form factors are thus expressed in terms of nucleon wave functions at small transverse separations, called distribution amplitudes, without any additional parameters. The distribution amplitudes, therefore, can be extracted from the comparison with the experimental data on form factors and compared to the results of lattice QCD simulations.