Nuclear Theory·nucl-th

Tuesday·November 20, 2018

28 papers—12 primary·16 cross-listed

01
[Submitted on 17 Nov 2018]
Sound velocity and tidal deformability in compact stars
Yong-Liang Ma🇨🇳 · Mannque Rho🇫🇷
The sound velocity $v_{s}$ and dimensionless tidal deformability $Λ$ are analyzed using the pseudo-conformal model we developed before. In contrast to the conclusion obtained in the previous works in the literature, our model with the upper bound of the sound velocity $v_{s} = 1/ 3$ , the so-called conformal sound velocity, set in at a { density relevant to compact stars} $\gsim 2 n_{0}$ where $n_{0}$ is the normal nuclear matter density, can accommodate {\it all} presently established nuclear matter and compact-star properties including the maximum star-mass constraint $≃ 2.3 M_{⊙}$ . This observation is associated with a possible emergence of pseudoconformal structure in compact star matter---in which the trace of energy-momentum tensor is a nearly density-independent nonzero constant---brought in by a topology change at $2.0 ≲ n_{1/2} / n_{0} ≲ 4.0$ commensurate with a possible change of degrees of freedom from hadrons.
Comments:
Version to appear in Phys. Rev. D
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
arXiv:
1811.07071 [pdf]
PRD(2019)·36 citations
02
[Submitted on 17 Nov 2018]
Nuclear electromagnetic dipole response with the Self-Consistent Green's Function formalism
F. Raimondi · C. Barbieri
Microscopic calculations of the electromagnetic response of medium-mass nuclei are now feasible thanks to the availability of realistic nuclear interactions with accurate saturation and spectroscopic properties, and the development of large-scale computing methods for many-body physics. The purpose is to compute isovector dipole electromagnetic (E1) response and related quantities, i.e. integrated dipole cross section and polarizability, and compare with data from photoabsorption and Coulomb excitation experiments. The single-particle propagator is obtained by solving the Dyson equation, where the self-energy includes correlations non-perturbatively through the Algebraic Diagrammatic Construction (ADC) method. The particle-hole ( $p h$ ) polarization propagator is treated in the Dressed Random Phase Approximation (DRPA), based on an effective correlated propagator that includes some $2 p 2 h$ effects but keeps the same computation scaling as the standard Hartree-Fock propagator. The E1 responses for $^{14, 16, 22, 24}$ O, $^{36, 40, 48, 52, 54, 70}$ Ca and $^{68}$ Ni have been computed: the presence of a soft dipole mode of excitation for neutron-rich nuclei is found, and there is a fair reproduction of the low-energy part of the experimental excitation spectrum. This is reflected in a good agreement with the empirical dipole polarizability values. For a realistic interaction with an accurate reproduction of masses and radii up to medium-mass nuclei, the Self-Consistent Green's Function method provides a good description of the E1 response, especially in the part of the excitation spectrum below the Giant Dipole Resonance. The dipole polarizability is largely independent from the strategy of mapping the dressed propagator to a simplified one that is computationally manageable
Comments:
14 pages, 12 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1811.07163 [pdf]
PRC(2019)·40 citations
03
[Submitted on 17 Nov 2018]
Deconfinement of non-strange hadronic matter with nucleons and $Δ$ baryons to quark matter in neutron stars
Debashree Sen🇮🇳 · T.K. Jha🇮🇳
We explore the possibility of formation of $Δ$ baryons (1232 MeV) in neutron star matter in an effective chiral model within the relativistic mean-field framework. With variation in delta-meson couplings, consistent with the constraints imposed on them, the resulting equation of state is obtained and the neutron star properties are calculated for static and spherical configuration. Within the framework of our model the critical densities of formation of $Δ$ s and the properties of neutron stars are found to be very sensitive to the iso-vector coupling compared to the scalar or vector couplings. We revisit the $Δ$ puzzle and look for the possibility of phase transition from non-strange hadronic matter (including nucleons and $Δ$ s) to deconfined quark matter, based on QCD theories. The resultant hybrid star configurations satisfy the observational constraints on mass from the most massive pulsars PSR J1614-2230 and PSR J0348+0432 in static condition obtained with the general hydrostatic equilibrium based on GTR. Our radius estimates are well within the limits imposed from observational analysis of QLMBXs. The obtained values of $R_{1.4}$ are in agreement with the recent bounds specified from the observation of gravitational wave (GW170817)from binary neutron star merger. The constraint on baryonic mass from study of binary system PSR J0737-3039 is also satisfied with our hybrid equation of state. \noindent{Keywords: Delta baryons, Quark matter, Phase transition, Equation of State, Neutron Stars, Hybrid Stars}
Comments:
30 pages, 19 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1811.07227 [pdf]
Int.J.Mod.Phys.D(2018)·12 citations
04
[Submitted on 18 Nov 2018]
Possible signals of two QCD phase transitions at NICA-FAIR energies
K. A. Bugaev🇺🇦 · A. I. Ivanytskyi🇺🇦 · V. V. Sagun🇺🇦 · B. E. Grinyuk🇺🇦 · D. O. Savchenko🇺🇦 · G. M. Zinovjev🇺🇦 · E. G. Nikonov🇷🇺 · L. V. Bravina🇳🇴 · E. E. Zabrodin🇷🇺 · D. B. Blaschke🇷🇺 · S. Kabana🇫🇷 · A. V. Taranenko🇷🇺
The chemical freeze-out irregularities found with the most advanced hadron resonance gas model and possible signals of two QCD phase transitions are discussed. We found that the center-of-mass collision energy range of tricritical endpoint of QCD phase diagram is [9; 9.2] GeV which is consistent both with QCD inspired exactly solvable model and with experimental findings.
Comments:
6 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1811.07420 [pdf]
EPJ Web Conf.(2019)·6 citations
05
[Submitted on 19 Nov 2018]
Effects of hadron-quark phase transition on properties of Neutron Stars
Debashree Sen🇮🇳 · T.K. Jha🇮🇳
We investigate the possible scenario of deconfinement of hyperon rich hadronic matter to quark matter at high densities and the resulting hybrid star (HS) properties are analyzed. In the relativistic mean-field framework, we construct the equation of state (EoS) of hadronic matter using the effective chiral model while the pure quark matter is described using the MIT Bag model. We revisit the hyperon puzzle and analyze the possibility of hadron-quark phase transition with proper choice of the bag constant. In static condition the maximum mass of the resultant HSs are in good agreement with the recent observational bounds on the same from high mass pulsars such as PSR J1614-2230 and PSR J0348+0432. On invoking the phenomenon of phase transition, the radius of canonical mass ( $R_{1.4}$ ) and value of $R_{1.6}$ predicted by the model lie within the range prescribed from binary neutron star (BNS) merger detected by the LIGO-Virgo collaboration in 2017. The surface redshift obtained for the HSs also satisfy the constraints from pulsars RX J0720.4-3125 and 1E 1207.4-5209. It is noteworthy that unlike several other works, we add no modifications to the original form of the Bag model to satisfy these recent observational and empirical constraints on NS properties. We also discuss the rotational aspects of the HSs by calculating the properties like rotational mass, radius, energy density, moment of inertia at different angular velocities. The maximum bound on rotational frequency from the rapidly rotating pulsars like PSR B1937+21 and PSR J1748-2446ad are satisfied with the HS configuration. We also test the universality of our hybrid EoS in terms of normalized moment of inertia.
Comments:
28 pages, 11 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1811.07434 [pdf]
J.Phys.G(2019)·25 citations
06
[Submitted on 19 Nov 2018]
Quarkonium dissociation in perturbative QCD
Juhee Hong🇰🇷 · Su Houng Lee🇰🇷
For weakly bound quarkonia, we rederive the next-to-leading order cross sections of quarkonium dissociation by partons that include the hard thermal loop (HTL) resummation. Our results calculated with an effective vertex from the Bethe-Salpeter amplitude reduce to those obtained by potential nonrelativistic QCD (pNRQCD) in the relevant kinematical limit, and they can be used in a wide temperature range applicable to heavy quark systems in heavy ion collisions. Based on the lattice computation of the temperature-dependent binding energy, our numerical analysis on $Υ (1 S)$ indicates that at high temperature the dominant mechanism for quarkonium dissociation is inelastic parton scattering as expected in the quasifree approximation, while it is the gluo-dissociation at low temperature. By comparing with the momentum diffusion coefficient of a heavy quark, we discuss possible O(g) corrections to the next-to-leading order thermal width.
Comments:
18 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1811.07607 [pdf]
PRC(2019)·8 citations
07
[Submitted on 19 Nov 2018]
$S$ -factor and scattering parameters from $^{3}$ He + $^{4}$ He $\to^{7}$ Be + $γ$ data
Xilin Zhang · Kenneth M. Nollett · Daniel R. Phillips
We use the next-to-leading-order (NLO) amplitude in an effective field theory (EFT) for $^{3}$ He + $^{4}$ He $\to^{7}$ Be + $γ$ to perform the extrapolation of higher-energy data to solar energies. At this order the EFT describes the capture process using an s-wave scattering length and effective range, the asymptotic behavior of $^{7}$ Be and its excited state, and short-distance contributions to the E1 capture amplitude. We use a Bayesian analysis to infer the multi-dimensional posterior of these parameters from capture data below 2 MeV. The total $S$ -factor $S (0) = 0.57 8_{- 0.016}^{+ 0.015}$ keV b at 68% degree of belief. We also find significant constraints on $^{3}$ He- $^{4}$ He scattering parameters.
Comments:
4 pages, 2 figures. Submitted to the proceedings of the 22nd International Conference on Few-body Problems in Physics, Caen, France, July 9-13, 2018. Uses svproc.cls
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1811.07611 [pdf]
Springer Proc.Phys.(2020)·6 citations
08
[Submitted on 19 Nov 2018]
Deep-inelastic and quasielastic electron scattering from $A = 3$ nuclei
A. J. Tropiano🇺🇸 · J. J. Ethier🇳🇱 · W. Melnitchouk🇺🇸 · N. Sato🇺🇸
We perform a combined analysis of inclusive electron scattering data from $A = 3$ nuclei in the deep-inelastic and quasielastic scattering regions, using Monte Carlo analysis methods and the nuclear weak binding approximation to establish the range over which the data can be described within the same theoretical framework. Comparison with quasielastic $^{3}$ He cross sections from SLAC and Jefferson Lab suggests that most features of the $x ≳ 1$ data can be reasonably well described in the impulse approximation with finite- $Q^{2}$ nuclear smearing functions for momentum transfers $Q^{2} ≳ 1$ GeV $^{2}$ . For the DIS region, we analyze the recent $^{3}$ He to deuterium cross section ratio from the Jefferson Lab E03-103 experiment to explore the possible isospin dependence of the nuclear effects. We discuss the implications of this for the MARATHON experiment at Jefferson Lab, and outline how a Bayesian analysis of $^{3}$ He, $^{3}$ H and deuterium data can robustly determine the free neutron structure function.
Comments:
45 pages, 14 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1811.07668 [pdf]
PRC(2019)·19 citations
09
[Submitted on 19 Nov 2018]
Fine structure of the pygmy quadrupole resonance in $^{112, 114}$ Sn isotopes
N. Tsoneva · M. Spieker · H. Lenske · A. Zilges
The electric quadrupole response in $^{112, 114}$ Sn isotopes is investigated by energy-density functional (EDF) and three-phonon quasiparticle-phonon model (QPM) theory with special emphasis on 2 $^{+}$ excitations located above the first collective quadrupole state and below 5 MeV. Additional quadrupole strength clustering as a sequence of states similar to the recently observed pygmy quadrupole resonance in $^{124}$ Sn is found. The spectral distributions and transition densities of these 2 $^{+}$ states show special features being compatible with oscillations of a neutron skin against the isospin-symmetric nuclear core. Furthermore, two new ( $p$ , $p^{'} γ$ ) Doppler-shift attenuation (DSA) coincidence experiments were performed at the SONIC@HORUS setup. Quadrupole states with excitation energies up to 4.2 MeV were populated in $^{112, 114}$ Sn. Lifetimes and branching ratios were measured allowing for the determination of the reduced quadrupole transition strengths to the ground state. A stringent comparison of the new data to EDF+QPM theory in $^{112}$ Sn and $^{114}$ Sn isotopes hints at the occurrence of a low-energy quadrupole mode of unique character which could be interpreted as pygmy quadrupole resonance.
Comments:
6 pages, 4 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1811.07739 [pdf]
NPA(2019)·15 citations
10
[Submitted on 19 Nov 2018]
Elucidating the multiplicity dependence of J/ $ψ$ production in proton-proton collisions with PYTHIA8
S. G. Weber🇩🇪 · A. Dubla🇩🇪 · A. Andronic🇩🇪 · A. Morsch🇨🇭
A study of prompt and non-prompt J/ $ψ$ production as a function of charged-particle multiplicity in inelastic proton--proton (pp) collisions at a centre-of-mass energy of $s$ = 13 TeV based on calculations using the PYTHIA8 Monte Carlo is reported. Recent experimental data shows an intriguing stronger-than-linear increase of the self-normalized J/ $ψ$ yield with multiplicity; several models, based on initial or final state effects, have been able to describe the observed behaviour. In this paper, the microscopic reasons for this behaviour, like the role of multiple parton interactions, colour reconnections and auto-correlations are investigated. It is observed that the stronger-than-linear increase and the transverse momentum ( $p_{T}$ ) dependence, contrary to what is predicted by the other available models, can be attributed to auto-correlation effects only. In absence of auto-correlation effects, the increase of the yield of J/ $ψ$ with multiplicity -- and in general for all hard processes -- is weaker than linear for multiplicities exceeding about three times the mean multiplicity. The possibility of disentangling auto-correlation effects from other physical phenomena by measuring the charged-particle multiplicity in different pseudo-rapidity and azimuthal regions relative to the J/ $ψ$ direction is investigated. In this regard, it is suggested to extend the experimental measurements of J/ $ψ$ production as a function of the charged-particle multiplicity by determining the multiplicity in several azimuthal regions and in particular in the Transverse region with respect to the direction of the J/ $ψ$ meson.
Comments:
12 pages, 14 figures: accepted by EPJC
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1811.07744 [pdf]
EPJC(2019)·61 citations
11
[Submitted on 19 Nov 2018]
The QCD Phase Diagram from Statistical Model Analysis
Reinhard Stock · Francesco Becattini · Marcus Bleicher · Jan Steinheimer
In high multiplicity nucleus-nucleus collisions baryon-antibaryon annihilation and regeneration occur during the final hadronic expansion phase, thus distorting the initial equilibrium multiplicity ratios. We quantify the modifications employing the hybrid UrQMD transport model and apply them to the grand canonical partition functions of the Statistical Hadronization Model(SHM). We analyze minimum bias and central Pb+Pb collision data at SPS and LHC energy. We explain the Pion to Proton ratio puzzle. We also reproduce the deuteron to proton ratio at LHC energy by the SHM, and by UrQMD after attaching a phase space coalescence process. We discuss the resulting (T, $μ_{B}$ ) diagram.
Comments:
Quark Matter 2018 proceedings. Talk presented by Reinhard Stock. Accepted version
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1811.07766 [pdf]
NPA(2019)·9 citations
12
[Submitted on 19 Nov 2018]
Error analysis of the parameters of the Skyrme N2LO pseudo-potential
P. Becker🇬🇧 · A. Pastore🇬🇧 · D. Davesne🇫🇷 · J. Navarro🇪🇸
We perform a detailed analysis of the parameters of the Skyrme SN2LO interaction. By mean of a covariance matrix analysis, we have been able to provide error bars and build the complete covariance matrix. The latter will be used in future applications to properly study the propagation of errors on nuclear observables calculated with this pseudo-potential.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1811.07866 [pdf]
Nuovo Cim.C(2019)·2 citations
13
[Submitted on 20 Aug 2018] (cross-list from hep-ph)
Vector mesons and electromagnetic form factor of the $Λ$ hyperon
Xu Cao🇨🇳 · Jian-Ping Dai🇨🇳 · Ya-Ping Xie🇨🇳
The measured electromagnetic form factors of $Λ$ hyperon in the time-like region are significantly deviated from pQCD prediction. We attribute the non-vanishing cross section near threshold to be the contribution of below-threshold $ϕ$ (2170) state, supporting its exotic structure. Above the threshold, we find significant role of a wide vector meson with the mass of around 2.34 GeV, which would be the same state present in $p p ˉ$ annihilation reactions. As a result, we give a satisfactory description of the behavior of existing data without modifying pQCD expectation.
Comments:
10 pages, 1 figure, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1808.06382 [pdf]
PRD(2018)·31 citations
14
[Submitted on 15 Nov 2018] (cross-list from hep-ph)
The spin parity of $Z_{c}^{-}$ (4100), $Z_{1}^{+}$ (4050) and $Z_{2}^{+}$ (4250)
Xu Cao🇨🇳 · Jian-Ping Dai🇨🇳
We conjecture that $Z_{c}^{-}$ (4100) found by LHCb group from a Dalitz plot analysis of $B^{0} \to η_{c} K^{+} π^{-}$ decay is the charge conjugate of $Z_{1}^{+}$ (4050) observed in $χ_{c 1} π^{+}$ distribution from Belle collaboration. Some interesting conclusions are inferred from this assumption. The $Z_{2}$ (4250) would be assigned to be a $J^{P} = 1^{+}$ or $1^{-}$ state because of its absence in $η_{c} π^{-}$ invariant mass distribution, while $Z_{1}^{+}$ (4050)/ $Z_{c}^{-}$ (4100) could be a $0^{+}$ or $1^{-}$ state but $2^{+}$ is unfavored because it would be coupled to $η_{c} π$ in $D$ -wave. The null observation of $Z_{1} Z_{2}$ , $Z_{1} Z_{1}$ and $Z_{2} Z_{2}$ production in $e^{+} e^{-}$ annihilation and $Υ (1 S, 2 S)$ decay by Belle collaboration would further allocate the spin parity combination of $Z_{1}^{+}$ (4050)/ $Z_{c}^{-}$ (4100) and $Z_{2}$ (4250). Our deductions can be used to exclude a set of proposed models and could be further tested by future experiment, e.g. in $γ γ$ collisions.
Comments:
10 pages,published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.06434 [pdf]
PRD(2019)·16 citations
15
[Submitted on 16 Nov 2018] (cross-list from hep-ph)
Soft drop groomed jet angularities at the LHC
Zhong-Bo Kang🇺🇸 · Kyle Lee🇺🇸 · Xiaohui Liu🇨🇳 · Felix Ringer🇺🇸
Jet angularities are a class of jet substructure observables where a continuous parameter is introduced in order to interpolate between different classic observables such as the jet mass and jet broadening. We consider jet angularities measured on an inclusive jet sample at the LHC where the soft drop grooming procedure is applied in order to remove soft contaminations from the jets. The soft drop algorithm allows for a precise comparison between theory and data and could be used to extract the QCD strong coupling constant $α_{s}$ from jet substructure data in the future. We develop a framework to realize the resummation of all relevant large logarithms at the next-to-leading logarithmic (NLL) accuracy. To demonstrate that the developed formalism is suitable for the extraction of $α_{s}$ , we extend our calculations to next-to-next-to-leading logarithm (NNLL) for the jet mass case. Overall, we find good agreement between our NLL numerical results and Pythia simulations for LHC kinematics and we observe an improved agreement when the NNLL components are included. In addition, we expect that groomed jet angularities will be a useful handle for studying the modification of jets in heavy-ion collisions.
Comments:
10 pages, 3 figures, published version in PLB
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1811.06983 [pdf]
PLB(2019)·80 citations
16
[Submitted on 16 Nov 2018] (cross-list from hep-ph)
Quarkonium In-Medium Transport Equation Derived from First Principles
Xiaojun Yao🇺🇸 · Thomas Mehen🇺🇸
We use the open quantum system formalism to study the dynamical in-medium evolution of quarkonium. The system of quarkonium is described by potential non-relativistic QCD while the environment is a weakly coupled quark-gluon plasma in local thermal equilibrium below the melting temperature of the quarkonium. Under the Markovian approximation, it is shown that the Lindblad equation leads to a Boltzmann transport equation if a Wigner transform is applied to the system density matrix. Our derivation illuminates how the microscopic time-reversibility of QCD is consistent with the time-irreversible in-medium evolution of quarkonium states. Static screening, dissociation and recombination of quarkonium are treated in the same theoretical framework. In addition, quarkonium annihilation is included in a similar way, although the effect is negligible for the phenomenology of the current heavy ion collision experiments. The methods used here can be extended to study quarkonium dynamical evolution inside a strongly coupled QGP, a hot medium out of equilibrium or cold nuclear matter, which is important to studying quarkonium production in heavy ion, proton-ion, and electron-ion collisions.
Comments:
29 pages, 1 figure, minor changes, version accepted by PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.07027 [pdf]
PRD(2019)·128 citations
17
[Submitted on 17 Nov 2018] (cross-list from cond-mat.quant-gas)
Leading Order $k_{F} a$ Corrections to the Free Energy and Phase Separation in Two-component Fermion Systems
Heron Caldas🇧🇷
We study phase separation in a dilute two-component Fermi system with attractive interactions as a function of the coupling strength and the polarization or number density asymmetry between the two components. In weak and strong couplings with a finite number density asymmetry, phase separation is energetically more favorable. A heterogeneous phase containing a symmetric superfluid component and an asymmetric normal phase has lower energy than a homogeneous normal phase. We show that for a small number density asymmetry, taking into consideration the leading order corrections at order $k_{F} a$ of the interaction parameter, phase separation is stable against the normal phase in the whole BCS range. We investigate the consequences of the consideration of the leading order $k_{F} a$ corrections to the thermodynamic potentials of the normal and BCS phase on the Chandrasekhar-Clogston limit. We have also investigated the stability of a Bose-Fermi mixture in the far-BEC limit. We find that the molecular BEC is locally stable against an external magnetic field $h$ , provided $∣ h ∣$ is smaller than the pairing gap $Δ_{g a p}$ .
Comments:
10 pages, 5 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); cond-mat.other (cond-mat.other); Superconductivity (cond-mat.supr-con); Nuclear Theory (nucl-th)
arXiv:
1811.07152 [pdf]
J.Stat.Mech.(2019)·0 citations
18
[Submitted on 17 Nov 2018] (cross-list from hep-ph)
Search for the $Σ^{*}$ state in $Λ_{c}^{+} \to π^{+} π^{0} π^{-} Σ^{+}$ decay by triangle singularity
Ju-Jun Xie🇨🇳 · Eulogio Oset🇪🇸
A $Σ^{*}$ resonance with spin-parity $J^{P} = 1/ 2^{-}$ and mass in the vicinity of the $K ˉ N$ threshold has been predicted in the unitary chiral approach and inferred from the analysis of CLAS data on the $γ p \to K^{+} π^{0} Σ^{0}$ reaction. In this work, based on the dominant Cabibbo favored weak decay mechanism, we perform a study of $Λ_{c}^{+} \to π^{+} π^{0} Σ^{*}$ with the possible $Σ^{*}$ state decaying into $π^{-} Σ^{+}$ through a triangle diagram. This process is initiated by $Λ_{c}^{+} \to π^{+} K ˉ^{*} N$ , then the $K ˉ^{*}$ decays into $K ˉ π$ and $K ˉ N$ produce the $Σ^{*}$ through a triangle loop containing $K ˉ^{*} N K ˉ$ which develops a triangle singularity. We show that the $π^{-} Σ^{+}$ state is generated from final state interaction of $K ˉ N$ in $S$ -wave and isospin $I = 1$ , and the $Λ_{c}^{+} \to π^{+} π^{0} π^{-} Σ^{+}$ decay can be used to study the possible $Σ^{*}$ state around the $K ˉ N$ threshold. The proposed decay mechanism can provide valuable information on the nature of the $Σ^{*}$ resonance and can in principle be tested by facilities such as LHCb, BelleII and BESIII.
Comments:
Version published in PLB
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1811.07247 [pdf]
PLB(2019)·27 citations
19
[Submitted on 18 Nov 2018] (cross-list from hep-ph)
Fate of the charm baryon $Λ_{c}$ in cold and hot nuclear matter
Shigehiro Yasui🇯🇵
I discuss the properties of the $Λ_{c}$ baryon in nuclear matter at zero or finite temperature. Starting from the Lagrangian based on the heavy-quark effective theory, I derive the effective Lagrangian for the $Λ_{c}$ baryon existing as an impurity particle. Adopting the one-loop calculation for nucleons, I derive the effective potential as the quantity for measuring the stability of the $Λ_{c}$ baryon in nuclear matter. The parameters in the Lagrangian are fitted to reproduce the scattering length of the nucleon and the $Λ_{c}$ baryon estimated in the lattice QCD simulations and the chiral extrapolations. I present that the $Λ_{c}$ baryon is bound in nuclei with the binding energy of about 20 MeV at normal nuclear-matter density. I discuss the case that the $Λ_{c}$ baryon moves with a constant velocity. I also discuss an increase of the nucleon number density near the $Λ_{c}$ baryon in nuclear matter, and show that the $Λ_{c}$ baryon is a useful probe to research the nuclear systems at high density.
Comments:
17 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.07286 [pdf]
PRC(2019)·7 citations
20
[Submitted on 18 Nov 2018] (cross-list from hep-lat)
Nucleon form factors and root-mean-square radii on a (10.8 fm $)^{4}$ lattice at the physical point
Eigo Shintani🇯🇵 · Ken-Ichi Ishikawa🇯🇵 · Yoshinobu Kuramashi🇯🇵 · Shoichi Sasaki🇯🇵 · Takeshi Yamazaki🇯🇵
We present the nucleon form factors and root-mean-square (RMS) radii measured on a (10.8 fm $)^{4}$ lattice at the physical point. We compute the form factors at small momentum transfer region in $q^{2} \leq 0.102$ GeV $^{2}$ with the standard plateau method choosing four source-sink separation times $t_{sep}$ from 0.84 to 1.35 fm to examine the possible excited state contamination. We obtain the electric and magnetic form factors and their RMS radii for not only the isovector channel but also the proton and neutron ones without the disconnected diagram. We also obtain the axial-vector coupling and the axial radius from the axial-vector form factor. We find that these three form factors do not show large $t_{sep}$ dependence in our lattice setup. On the other hand, the induced pseudoscalar and pseudoscalar form factors show the clear effects of the excited state contamination, which affect the generalized Goldberger-Treiman relation.
Comments:
24 pages, 27 figures, published version. Erratum is appended to original version. We corrected the normalization factors in our analysis code, and then recalculated the form factors with the correct normalization factors
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1811.07292 [pdf]
PRD(2019)·132 citations
21
[Submitted on 18 Nov 2018] (cross-list from hep-ph)
Light pseudoscalar meson and doubly charmed baryon scattering lengths with heavy diquark-antiquark symmetry
Lu Meng🇨🇳 · Shi-Lin Zhu🇨🇳
We adopt the heavy baryon chiral perturbation theory (HBChPT) to calculate the scattering lengths of $ϕ B_{cc}^{(*)}$ up to $O (p^{3})$ , where $ϕ$ is the pseudoscalar mesons. The recoil effect and the mass splitting between the spin- $\frac{1}{2}$ and spin- $\frac{3}{2}$ doubly charmed baryons are included. In order to give the numerical results, we construct the chiral Lagrangians with heavy diquark-antiquark (HDA) symmetry in a formally covariant approach. Then, we relate the low energy constants (LECs) of the doubly charmed baryons to those of $D^{(*)}$ mesons. The LECs for the $ϕ D^{(*)}$ scattering are estimated in two scenarios, fitting lattice QCD results and using the resonance saturation model. The chiral convergence of the first scenario is not good enough due to the the large strange quark mass and the presence of the possible bound states, virtual states and resonance. The final results for two scenarios are consistent with each other. The interaction for the $[π Ξ_{cc}^{(*)}]^{(1/2)}$ , $[K Ξ_{cc}^{(*)}]^{(0)}$ , $[K Ω_{cc}^{(*)}]^{(1/2)}$ , $[η Ξ_{cc}^{(*)}]^{(1/2)}$ , $[η Ω_{cc}^{(*)}]^{(0)}$ and $[K ˉ Ξ_{cc}^{(*)}]^{(0)}$ channels are attractive. The most attractive channel $[K ˉ Ξ_{cc}^{(*)}]^{(0)}$ may help to form the partner states of the $D_{s 0}^{*} (2317)$ ( $D_{s 1} (2460)$ ) in the doubly heavy sector.
Comments:
12 pages, 2 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1811.07320 [pdf]
PRD(2019)·27 citations
22
[Submitted on 18 Nov 2018] (cross-list from hep-ph)
Zero point energy of composite particles: The medium effects
Toru Kojo🇨🇳
We analyze the zero point energy of composite particles (or resonances) which are dynamically created from relativistic fermions. We compare the zero point energies in medium to the vacuum one, taking into account the medium modification of the constituent particles. Treating composite particles as if quasi-particles, their zero point energies contain the quadratic and logarithmic UV divergences even after the vacuum subtraction. The coefficients of these divergences come from the difference between the vacuum and in-medium fermion propagators. We argue that such apparent divergences can be cancelled by consistently using fermion propagators to compute the quasi-particle contributions as well as their interplay, provided that the self-energies of the constituents at large momenta approach to the vacuum ones sufficiently fast. In the case of quantum chromodynamics, mesons and baryons, which may be induced or destroyed by medium effects, yield the in-medium divergences in the zero point energies, but the divergences are assembled to cancel with those from the quark zero-point energy. This is particularly important for unified descriptions of hadronic and quark matter which may be smoothly connected by the quark-hadron continuity.
Comments:
v3) 32 pages, 13 figures; published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1811.07363 [pdf]
PRD(2020)·5 citations
23
[Submitted on 19 Nov 2018] (cross-list from hep-ph)
Studying parton correlations via double parton scatterings in associated quarkonium production at the LHC and the Tevatron
Nodoka Yamanaka🇫🇷 · Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇫🇷 · Yu-Jie Zhang🇨🇳
Quarkonium production in proton-proton (pp) collision provides interesting means to study the parton content and their correlations in the proton. Recent LHC and Tevatron data of J/psi + Z, J/psi + W and J/psi +J/psi production suggest the relevance of double parton scatterings (DPSs) as opposed to single parton scatterings (SPSs). In this proceedings contribution, we review the corresponding SPS contributions and discuss their upper limits set up by quark-hadron duality. These allow us to perform an improved extraction of the DPS yields and of their implications.
Comments:
4 pages, 5 figures, Proceedings of the XXXIX International Conference on High Energy Physics (ICHEP2018), 4-11 July 2018, Seoul, Korea
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1811.07474 [pdf]
PoS(2019)·1 citation
24
[Submitted on 19 Nov 2018] (cross-list from hep-ph)
Dilepton production and elliptic flow from an anisotropic quark-gluon plasma
Babak S. Kasmaei🇺🇸 · Michael Strickland🇺🇸
We calculate the yield and elliptic flow of mid-rapidity dileptons emitted from the quark-gluon plasma generated in Pb-Pb collisions at LHC. We use relativistic anisotropic hydrodynamics for the 3+1 dimensional evolution of the quark-gluon plasma and convolve this with the momentum-anisotropic local rest frame production rate for dileptons. The effects of momentum anisotropy of the quark distribution functions, viscosity to entropy density ratio, centrality of the collisions, and initial momentum anisotropy on the results are investigated and discussed.
Comments:
26 pages, 13 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.07486 [pdf]
PRD(2019)·39 citations
25
[Submitted on 19 Nov 2018] (cross-list from hep-ph)
Searching for the Odderon in the diffractive $f_{2} (1270)$ photoproduction at $p A$ collisions
V. P. Goncalves🇧🇷
Although the Odderon is an unambiguous prediction of Quantum Chromodynamics, its existence still was not confirmed experimentally. One of the processes where the Odderon contribution is expected to be dominant is the diffractive photoproduction of tensor mesons. In this paper we study the diffractive $f_{2} (1270)$ photoproduction in $p A$ collisions at LHC and RHIC considering the model of the stochastic vacuum to treat the non - perturbative process. We demonstrate that this process dominates the $f_{2}$ production at mid - rapidities, and large values for the cross section are predicted. Our results indicate that the experimental analysis of this final state is, in principle, feasible and can be used to probe the Odderon.
Comments:
5 pages, 1 figure, 1 table. Matches the version published in EPJC
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1811.07622 [pdf]
EPJC(2019)·8 citations
26
[Submitted on 19 Nov 2018] (cross-list from hep-ph)
Correction to the energy spectrum of $^{1} S_{0}$ heavy quarkonia due to two-gluon annihilation effect
Hui-Yun Cao🇨🇳 · Hai-Qing Zhou🇨🇳
In this work, the non-relativistic asymptotic behavior of the transition $q q \to 2 g \to q q$ in the $^{1} S_{0}$ channel is discussed. Different with the usual calculation which expands the physical amplitude around the quark anti-quark threshold, we take the quark anti-quark pairs as off shell and only expand the expression on the three-dimensional momenta of the quarks and anti-quarks. We calculate the results to order 6. The imagine part of the results after applying the on shell conditions can reproduce the non-relativistic QCD (NRQCD) results in leading order of $α_{s}$ . The real part of the results can be used to estimate the mass shift of the $^{1} S_{0}$ heavy quark anti-quark system due to the $2 g$ annihilation effect. The results can also be used to estimate the energy shifts of the positronium system due to the two-photon annihilation.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.07634 [pdf]
PRD(2019)·2 citations
27
[Submitted on 19 Nov 2018] (cross-list from hep-ph)
Centrality and energy dependence of charged particles in p+A and A+A collisions from running coupling $k_{T}$ -factorization
Adrian Dumitru🇺🇸 · Andre V. Giannini🇧🇷 · Matthew Luzum🇧🇷 · Yasushi Nara🇯🇵
We extend the numerical analysis of the energy and centrality dependence of particle multiplicities at midrapidity in high-energy p+A and A+A collisions from a running coupling $k_{T}$ -factorization formula made in~\cite{Dumitru:2018gjm} by considering two unintegrated gluon distributions that were left out. While a good agreement with the experimental data in A+A collisions is achieved, improving the description of those observables in p+A collisions calls for a better understanding of the proton unintegrated gluon distribution at larger values of $x$ and also the use of a realistic impact parameter dependence.
Comments:
6 pages, 4 figures. Proceedings of the Diffraction and Low-x 2018 conference. To be published in Acta Physica Polonica B Proceeding Supplement
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1811.07696 [pdf]
Acta Phys.Polon.Supp.(2019)·3 citations
28
[Submitted on 19 Nov 2018] (cross-list from hep-ph)
Three-loop formula for quark and gluon contributions to the QCD trace anomaly
Kazuhiro Tanaka (Juntendo Univ.)🇯🇵
In the QCD energy-momentum tensor $T^{μν}$ , the terms that contribute to physical matrix elements are expressed as the sum of the gauge-invariant quark part and gluon part. Each part undergoes the renormalization due to the interactions among quarks and gluons, although the total tensor $T^{μν}$ is not renormalized thanks to the conservation of energy and momentum. Recently it has been shown that, through the renormalization, each of the quark and gluon parts of $T^{μν}$ receives a definite amount of anomalous trace contribution, such that their sum reproduces the well-known QCD trace anomaly, $T_{μ}^{μ} = (β /2 g) F^{μν} F_{μν} + m (1 + γ_{m}) ψ ˉ ψ$ , and the corresponding formulas have been derived up to two-loop order. We extend this result to the three-loop order, working out all the relevant three-loop renormalization structure for the quark and gluon energy-momentum tensors in the (modified) minimal subtraction scheme in the dimensional regularization. We apply our three-loop formula of the quark/gluon decomposition of the trace anomaly to calculate the anomaly-induced mass structure of nucleons as well as pions.
Comments:
26 pages, text improved and references added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1811.07879 [pdf]
JHEP(2019)·49 citations

Affiliations

first authorsco-authorsvia INSPIRE