Nuclear Theory·nucl-th

Thursday·August 12, 2021

8 papers—3 primary·5 cross-listed

04
Temperature dependence of the properties of open heavy-flavor mesons
Gloria Montana🇪🇸 · Angels Ramos🇪🇸 · Laura Tolos🇪🇸 · Juan M. Torres-Rincon🇩🇪
We address the modification of open heavy-flavor mesons in a hot medium of light mesons within an effective theory approach consistent with chiral and heavy-quark spin-flavor symmetries and the use of the imaginary time formalism to introduce the non-zero temperature effects to the theory. The unitarized scattering amplitudes, the ground-state self-energies and the corresponding spectral functions are calculated self-consistently. We use the thermal ground-state spectral functions obtained with this methodology to further calculate 1) open-charm meson Euclidean correlators, and 2) off-shell transport coefficients in the hadronic phase.
↳ hep-phnucl-thEPJ Web Conf.(2022)·3 citations
05
Pion charge radius from pion+electron elastic scattering data
Zhu-Fang Cui🇨🇳 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪
With the aim of extracting the pion charge radius, we analyse extant precise pion+electron elastic scattering data on $Q^{2} \in [0.015, 0.144]$ GeV $^{2}$ using a method based on interpolation via continued fractions augmented by statistical sampling. The scheme avoids any assumptions on the form of function used for the representation of data and subsequent extrapolation onto $Q^{2} ≃ 0$ . Combining results obtained from the two available data sets, we obtain $r_{π} = 0.640 (7)$ fm, a value $2.4 σ$ below today's commonly quoted average. The tension may be relieved by collection and similar analysis of new precise data that densely cover a domain which reaches well below $Q^{2} = 0.015$ GeV $^{2}$ . Considering available kaon+electron elastic scattering data sets, our analysis reveals that they contain insufficient information to extract an objective result for the charged-kaon radius, $r_{K}$ . New data with much improved precision, low- $Q^{2}$ reach and coverage are necessary before a sound result for $r_{K}$ can be recorded.
↳ hep-phhep-exhep-latnucl-ex+1PLB(2021)·26 citations
06
Shear viscosity at finite baryon densities
Emma McLaughlin🇺🇸 · Jacob Rose🇩🇪 · Travis Dore🇺🇸 · Paolo Parotto🇩🇪 · Claudia Ratti🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸
We use the excluded volume Hadron Resonance Gas (HRG) model with the most up-to-date hadron list to calculate $η T / w$ at low temperatures and at finite baryon densities $ρ_{B}$ . This $η T / w$ is then matched to a QCD-based shear viscosity calculation of the QGP for different profiles of $η T / w$ across {T, $μ_{B}$ } including cross-over and critical point transitions. When compared to ideal hydrodynamic trajectories across {T, $μ_{B}$ }, we find that the $η T / w (T, μ_{B})$ profiles would require initial conditions at much larger baryon density to reach the same freeze-out point.
↳ hep-phnucl-thEPJ Web Conf.(2022)·1 citation
07
Interpretations of the new LHCb $P_{c} (4337)^{+}$ pentaquark state
Mao-Jun Yan🇨🇳 · Fang-Zheng Peng🇨🇳 · Mario Sánchez Sánchez🇫🇷 · Manuel Pavon Valderrama🇨🇳
Recently the LHCb collaboration has observed a new pentaquark state, the $P_{c} (4337)^{+}$ . Owing to its proximity to the $χ_{c 0} (1 S) p$ , $D ˉ^{*} Λ_{c}$ , $D ˉ Σ_{c}$ and $D ˉ Σ_{c}^{*}$ thresholds, this new pentaquark might very well be a meson-baryon bound state. However its spin and parity have not been determined yet and none of the previous possibilities can be ruled out. We briefly explore a few of these options and the consequences they entail in the present manuscript: (i) the $P_{c} (4337)^{+}$ might be a $χ_{c 0} (1 S) p$ bound state, (ii) the $P_{c} (4312)^{+}$ and $P_{c} (4337)^{+}$ might be $D ˉ^{*} Λ_{c}$ and $D ˉ Σ_{c}$ states close to threshold, respectively, where the Breit-Wigner mass might not correspond to the location of the poles, (iii) the locations of the $P_{c} (4312)^{+}$ and $P_{c} (4337)^{+}$ might be explained in terms of the $D ˉ^{*} Λ_{c}$ - $D ˉ Σ_{c}$ and $D ˉ^{*} Λ_{c}$ - $D ˉ Σ_{c}^{*}$ coupled channel dynamics. This last option, though not the most probable explanation, is still potentially compatible with the double peak solution of the $P_{cs} (4459)^{0}$ and with what we know of the $P_{c} (4312)^{+}$ . As a byproduct of the previous explorations, we conjecture the existence of a series of anticharmed meson - antitriplet charmed baryon bound states and calculate their masses.
↳ hep-phhep-exnucl-thEPJC(2022)·33 citations
08
Final State Gluon Emission in Deep-Inelastic Scattering at Next-to-Leading Twist
Chathuranga Sirimanna🇺🇸 · Shanshan Cao🇺🇸 · Abhijit Majumder🇺🇸
A detailed reanalysis of the single gluon emission rate at next-to-leading twist is carried out. As was the case in prior efforts, the problem is cast in the framework of deep-inelastic scattering (DIS) of an electron off a large nucleus. The quark produced in the interaction propagates through the remaining nucleus and engenders scattering and gluon radiation, which is calculated in the limit of one re-scattering. This medium induced single gluon emission rate forms the basis of several energy loss calculations in both DIS and heavy-ion collisions. Unlike prior efforts, a complete transverse momentum gradient expansion of the hadronic tensor, including $N_{c}$ suppressed terms, phase terms and finite gluon momentum fraction terms, ignored previously, is carried out. These terms turn out to be surprisingly large. In contrast to prior efforts, the full next-to-leading twist gluon emission kernel is found to be positive definite and slowly increasing with the exchanged transverse momentum. Phenomenological consequences of these new contributions are discussed.
↳ hep-phnucl-exnucl-thPRC(2022)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE

Temperature dependence of the properties of open heavy-flavor mesons

Pion charge radius from pion+electron elastic scattering data

Shear viscosity at finite baryon densities

Interpretations of the new LHCb Pc​(4337)+ pentaquark state

Final State Gluon Emission in Deep-Inelastic Scattering at Next-to-Leading Twist

Affiliations

Interpretations of the new LHCb $P_{c} (4337)^{+}$ pentaquark state