Nuclear Theory·nucl-th

Friday·October 20, 2023

9 papers—2 primary·7 cross-listed

01
Does Quarkonia Suppression serve as a probe for the deconfinement in small systems?
Partha Bagchi🇮🇳 · Arpan Das🇮🇳 · Ananta P. Mishra🇮🇳
In high multiplicity proton-proton $(p - p)$ collisions, the formation of a deconfined state of quarks and gluons akin to Heavy Ion Collisions (HIC) has been a subject of significant interest. In proton-proton ( $p - p$ ) collisions, the transverse size of the system is comparable to the longitudinal (Lorentz contracted) dimension, unlike the case in Nucleus-Nucleus ( $A - A$ ) collision, leading to a hitherto unexplored effect of rapid decrease of temperature of the medium on quark-antiquark bound states. This allows us to probe a unique possibility of hadronization occurring before quarkonia dissociation within the medium. In small systems, a rapid change in temperature also introduces sudden changes in the Hamiltonian. This scenario prompts consideration of non-adiabatic evolution, challenging the traditional adiabatic framework. We demonstrate that non-adiabatic evolution may extend the longevity of quark-anti-quark bound states in $p - p$ collisions, even at higher multiplicities, offering new insights into the dynamics of strongly interacting matter produced in smaller collision systems.
nucl-thhep-phPRD(2024)·9 citations
02
Gravitational form factors of light nuclei: Impulse approximation
Fangcheng He🇺🇸 · Ismail Zahed🇺🇸
The gravitational form factors of light nuclei are evaluated up to momenta of the order of the nucleon mass, using the impulse approximation. The nucleon gravitational form factors are reduced non-relativistically, and used to derive the gravitational form factors of light nuclei. The deuteron gravitational form factors are analysed using the Reid soft core potential. The helium-4 gravitational form factors are assessed using the K-harmonics method, and compared to those following from a mean-field approximation with a Woods-Saxon potential. The importance of removing the center of mass motion for the ensuing form factors is emphasized. The mass radii of these light nuclei are extracted and compared to their charge radii counterparts. The details of their pressure and shear distributions are discussed.
nucl-thhep-phPRC(2024)·11 citations
03
Vanishing Polyakov Loop for QCD with Twelve Massless Quarks
Seth Grable🇺🇸 · Paul Romatschke🇺🇸
We consider continuum-formulation QCD in four dimensions with twelve massless fundamental quark flavors. Splitting the SU($N$) gauge field into background and fluctuation parts, we use well-developed techniques to calculate the one-loop effective action for the theory. We find that for constant self-dual background field-strength tensor the notorious infrared divergences of the effective action cancel between gauge and matter sectors if the number of massless quark flavors is exactly . The ultraviolet divergencies of the effective action are non-perturbatively renormalized with a $β$ -function that matches the known perturbative result in the high energy limit. The resulting UV- and IR-finite effective action possesses a non-trivial saddle which has lower free energy than the perturbative vacuum, and for which the expectation value of the Polyakov loop vanishes. Inclusion of finite temperature effects points to the presence of a first-order phase transition to the perturbative vacuum with a calculable critical temperature.
↳ hep-thhep-phnucl-thPLB(2025)·7 citations
04
Two-detector flavor sensitivity to ultra-high-energy cosmic neutrinos
Federico Testagrossa🇮🇹 · Damiano F. G. Fiorillo🇩🇰 · Mauricio Bustamante🇩🇰
Ultra-high-energy (UHE) cosmic neutrinos, with energies above 100 PeV, could be finally discovered in the near future. Measuring their flavor composition would reveal information about their production and propagation, but new techniques are needed for UHE neutrino telescopes to have the capabilities to do it. We address this by proposing a new way to measure the UHE neutrino flavor composition that does not rely on individual telescopes having flavor-identification capabilities. We manufacture flavor sensitivity from the joint detection by one telescope sensitive to all flavors -- the radio array of IceCube-Gen2 -- and one mostly sensitive to $ν_{τ}$ -- GRAND. From this limited flavor sensitivity, predominantly to $ν_{τ}$ , and even under conservative choices of neutrino flux and detector size, we extract important insight. For astrophysics, we forecast meaningful constraints on the neutrino production mechanism; for fundamental physics, vastly improved constraints on Lorentz-invariance violation. These are the first measurement forecasts of the UHE $ν_{τ}$ content.
↳ astro-ph.HEhep-exhep-phnucl-thPRD(2024)·15 citations
05
Internal structures of the baryons $Ξ (2030)$ and $Ξ (2120)$
Hao Hei🇨🇳 · Yin Huang🇨🇳
Currently, there is much controversy surrounding the interpretation of the $Ξ (2030)$ and $Ξ (2012)$ as traditional hadrons containing double strange quarks. In particular, the ratios of the partial decay widths into $Λ K ˉ$ and $Σ K ˉ$ for $Ξ (2030)$ cannot obtain a suitable explanation under the $q ss$ three quark structure~\cite{Xiao:2013xi}. Thus, we suggest the $Ξ (2030)$ and $Ξ (2012)$ to be $V B (= K ˉ^{*} Σ/ ρ Ξ/ K ˉ^{*} Λ/ ϕ Ξ/ ω Ξ)$ molecular states. In this work, we perform a systematical investigation of possible molecular states from the $V B (= K ˉ^{*} Σ/ ρ Ξ/ K ˉ^{*} Λ/ ϕ Ξ/ ω Ξ)$ interaction. The interaction of the system considered is described by the $t$ -channel vector ( $ρ, ω, ϕ, K ˉ^{*}$ ) and pseudoscalar ( $π, η, K ˉ$ ) mesons exchanges. By solving the non-relativistic Schrödinger equation with the obtained one-boson-exchange potentials, the $V B (= K ˉ^{*} Σ/ ρ Ξ/ K ˉ^{*} Λ/ ϕ Ξ/ ω Ξ)$ bound states with different quantum numbers are searched. The calculation suggests that $Ξ (2030)$ can be assigned as a $P$ -wave $K ˉ^{*} Σ/ ρ Ξ/ K ˉ^{*} Λ/ ϕ Ξ/ ω Ξ$ molecular state with spin parity $J^{P} = 5/ 2^{+}$ . The calculation also predict the existence of four $K ˉ^{*} Σ/ ρ Ξ/ K ˉ^{*} Λ/ ϕ Ξ/ ω Ξ$ bound states with $J^{P} = 1/ 2^{\pm}$ and $J^{P} = 3/ 2^{\pm}$ . The $Ξ (2012)$ may be a candidate for one of these four bound states. If $Ξ (2012)$ is an $S$ -wave molecular state with $J^{P} = 1/ 2^{-}$ or $J^{P} = 3/ 2^{-}$ , we suggest determining its spin and parity by studying its decay width, owing to the difference in their molecular components.
↳ hep-phnucl-thPRD(2024)·6 citations
06
Chiral Analysis of the Nucleon Mass and Sigma Commutator
Shiryo Owa🇦🇺 · Derek B. Leinweber🇦🇺 · Anthony W. Thomas🇦🇺 · Xuan-Gong Wang🇦🇺
Schemes for describing the light quark mass dependence of the nucleon mass calculated in lattice QCD are compared. The three schemes in consideration include a fully relativistic and Lorentz covariant scheme, one that is fully relativistic but not Lorentz covariant, and a semirelativistic scheme utilizing the heavy baryon approximation. Calculations of observables involving pseudoscalar meson loop diagrams generate nonanalytic terms proportional to square roots and logarithms of the quark mass. The three schemes all yield the correct model independent leading and next-to-leading nonanalytic terms of the chiral expansion of the baryon mass. Results for the masses of the other members of the octet are also presented. Here, low-energy coefficients of the analytic terms of the expansion for the nucleon and hyperons are constrained by lattice QCD results and are demonstrated to be independent of the renormalization scheme used. The differences in the leading coefficient of the chiral expansions are found to be consistent with strange quark counting. Using the schemes examined herein, we report results for the pion-nucleon sigma commutator based upon recent lattice results from the CLS Collaboration. We find $σ_{π N} = 51.7 \pm 3.2 \pm 1.4$ MeV where the uncertainties are statistical and systematic respectively.
↳ hep-phhep-latnucl-thPRD(2024)·5 citations
07
Energy dependence of $J / ψ$ production in pp collisions with the PACIAE model
Kai-Fan Ye🇨🇳 · Qiang Wang🇨🇳 · Jia-Hao Shi🇨🇳 · Zhi-Ying Qin🇨🇳 · Wen-Chao Zhang🇨🇳 · An-Ke Lei🇨🇳 · Zhi-Lei She🇨🇳 · Yu-Liang Yan🇨🇳 · Ben-Hao Sa🇨🇳
In this work we investigate the $J / ψ$ production in proton-proton collisions at the center-of-mass energy ( $s$ ) equal to 2.76, 5.02, 7, 8 and 13 TeV with a parton and hadron cascade model PACIAE 2.2a. It is based on PYTHIA but extended considering the partonic and hadronic rescatterings before and after hadronization, respectively. In the PYTHIA sector the $J / ψ$ production quantum chromodynamics processes are selected specially and a bias factor is proposed correspondingly. The calculated total cross sections, the differential cross sections as a function of the transverse momentum and the rapidity of $J / ψ$ in the forward rapidity region reproduce the corresponding experimental measurements reasonably well. In the mid-rapidity region, the double differential cross sections at $s =$ 5.02, 7 and 13 TeV are also in a good agreement with the experimental data. Moreover, we interpolate the double differential cross section as well as the total cross section of $J / ψ$ in the mid-rapidity region at $s =$ 8 TeV, which could be validated if the experimental data is available.
↳ hep-phnucl-thPRC(2024)·6 citations
08
Semi-inclusive two-nucleon emission in (anti) neutrino CC scattering within the relativistic mean field framework
V.L. Martinez-Consentino🇪🇸 · A.M. Cantizani🇪🇸 · J.E. Amaro🇪🇸
This paper delves into the distribution of semi-inclusive events involving the emission of two nucleons in (anti) neutrino charged-current scattering. The analysis is conducted within the framework of relativistic mean field theory applied to nuclear matter. To quantify the likelihood of such semi-inclusive events occurring, we employ a relativistic model of meson-exchange currents that aligns with the 2p2h inclusive cross-section. The outcomes are presented in terms of one-fold and two-fold integrated semi-inclusive cross sections. To highlight disparities among the various emission channels, including proton-proton, neutron-proton, and neutron-neutron, we compare them against a purely phase-space isotropic distribution within the center of mass of the two nucleons. These comparisons reveal significant differences in the event distributions, shedding light on the distinctive characteristics of each channel.
↳ hep-phnucl-thPRC(2024)·12 citations
09
Correspondence between Color Glass Condensate and High-Twist Formalism
Yu Fu🇨🇳 · Zhong-Bo Kang🇺🇸 · Farid Salazar🇺🇸 · Xin-Nian Wang🇨🇳 · Hongxi Xing🇨🇳
The Color Glass Condensate (CGC) effective theory and the collinear factorization at high-twist (HT) are two well-known frameworks describing perturbative QCD multiple scatterings in nuclear media. It has long been recognized that these two formalisms have their own domain of validity in different kinematics regions. Taking direct photon production in proton-nucleus collisions as an example, we clarify for the first time the relation between CGC and HT at the level of a physical observable. We show that the CGC formalism beyond shock-wave approximation, and with the Landau-Pomeranchuk-Migdal interference effect is consistent with the HT formalism in the transition region where they overlap. Such a unified picture paves the way for mapping out the phase diagram of parton density in nuclear medium from dilute to dense region.
↳ hep-phhep-exnucl-exnucl-thPRL(2025)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE