Nuclear Theory·nucl-th

Monday·September 4, 2023

9 papers—4 primary·5 cross-listed

05
[Submitted on 31 Aug 2023] (cross-list from nucl-ex)
Semi-inclusive direct photon+jet and $π^{0}$ +jet correlations measured in $p + p$ and central Au+Au collisions at $s_{NN} = 200$ GeV
The STAR Collaboration
The STAR experiment at RHIC reports new measurements of jet quenching based on the semi-inclusive distribution of charged-particle jets recoiling from direct photon ( $γ_{dir}$ ) and neutral pion ( $π^{0}$ ) triggers in pp and central Au+Au collisions at $s_{NN} = 200$ GeV, for triggers in the range $9 < E_{T}^{trig} < 20$ GeV. The datasets have integrated luminosities of 3.9 $nb^{- 1}$ for Au+Au and 23 $pb^{- 1}$ for pp collisions. Jets are reconstructed using the anti- $k_{T}$ algorithm with resolution parameters $R$ =0.2 and 0.5. The large uncorrelated jet background in central Au+Au collisions is corrected using a mixed-event approach, which enables precise charged-particle jet measurements at low transverse momentum $p_{T, jet}^{ch}$ and large $R$ . Recoil-jet distributions are reported in the range $p_{T, jet}^{ch} < 25$ \gev. Comparison of the distributions measured in pp and Au+Au collisions reveals strong medium-induced jet yield suppression for $R = 0.2$ , with markedly less suppression for $R = 0.5$ . Comparison is also made to theoretical models incorporating jet quenching. These data provide new insight into the mechanisms underlying jet quenching and the angular dependence of medium-induced jet-energy transport, and provide new constraints on modelling such effects.
Comments:
Accepted by PRC along with companion PRL paper arXiv:2309.00156
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2309.00145 [pdf]
PRC(2025)·21 citations
06
[Submitted on 31 Aug 2023] (cross-list from nucl-ex)
Measurement of in-medium jet modification using direct photon+jet and $π^{0}$ +jet correlations in $p + p$ and central Au+Au collisions at $s_{NN} = 200$ GeV
STAR Collaboration
The STAR Collaboration presents measurements of the semi-inclusive distribution of charged-particle jets recoiling from energetic direct-photon ( $γ_{dir}$ ) and neutral-pion ( $π^{0}$ ) triggers in p+p and central Au+Au collisions at $s_{NN}$ GeV over a broad kinematic range, for jet resolution parameters $R$ =0.2 and 0.5. Medium-induced jet yield suppression is observed to be larger for $R$ =0.2 than for 0.5, reflecting the angular range of jet energy redistribution due to quenching. The predictions of model calculations incorporating jet quenching are not fully consistent with the observations. These results provide new insight into the physical origins of jet quenching.
Comments:
Accepted by PRL, companion paper submitted to PRC arXiv:2309.00145
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2309.00156 [pdf]
PRL(2025)·21 citations
07
[Submitted on 1 Sept 2023] (cross-list from hep-ph)
Correlation function for the $T_{bb}$ state: Determination of the binding, scattering lengths, effective ranges and molecular probabilities
A. Feijoo🇪🇸 · L. R. Dai🇨🇳 · L. M. Abreu🇧🇷 · E. Oset🇪🇸
We perform a study of the $B^{*+} B^{0}, B^{* 0} B^{+}$ correlation functions using an extension of the local hidden gauge approach which provides the interaction from the exchange of light vector mesons and gives rise to a bound state of these components in $I = 0$ with a binding energy of about $21$ ~MeV. After that, we face the inverse problem of determining the low energy observables, scattering length and effective range for each channel, the possible existence of a bound state, and, if found, the couplings of such a state to each $B^{*+} B^{0}, B^{* 0} B^{+}$ component as well as the molecular probabilities of each of the channels. We use the bootstrap method to determine these magnitudes and find that, with errors in the correlation function typical of present experiments, we can determine all these magnitudes with acceptable precision. In addition, the size of the source function of the experiment from where the correlation functions are measured can be also determined with a high precision.
Comments:
7 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2309.00444 [pdf]
PRD(2024)·30 citations
08
[Submitted on 1 Sept 2023] (cross-list from hep-th)
Schwinger-Keldysh effective field theory for stable and causal relativistic hydrodynamics
Akash Jain🇳🇱 · Pavel Kovtun🇨🇦
We construct stable and causal effective field theories (EFTs) for describing statistical fluctuations in relativistic diffusion and relativistic hydrodynamics. These EFTs are fully non-linear, including couplings to background sources, and enable us to compute n-point time-ordered correlation functions including the effects of statistical fluctuations. The EFTs we construct are inspired by the Maxwell-Cattaneo model of relativistic diffusion and Müller-Israel-Stewart model of relativistic hydrodynamics respectively, and have been derived using both the Martin-Siggia-Rose and Schwinger-Keldysh formalisms. The EFTs non-linearly realise the dynamical Kubo-Martin-Schwinger (KMS) symmetry, which ensures that n-point correlation functions and interactions in the theory satisfy the appropriate fluctuation-dissipation theorems. Since these EFTs typically admit ultraviolet sectors that are not fixed by the low-energy infrared symmetries, we find that they simultaneously admit multiple realisations of the dynamical KMS symmetry. We also comment on certain obstructions to including statistical fluctuations in the recently-proposed stable and causal Bemfica-Disconzi-Noronha-Kovtun model of relativistic hydrodynamics.
Comments:
47+1 pages
Subjects:
High Energy Physics — Theory (hep-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
2309.00511 [pdf]
JHEP(2024)·39 citations
09
[Submitted on 1 Sept 2023] (cross-list from hep-th)
Relativistic hydrodynamic fluctuations from an effective action: causality, stability, and the information current
Nicki Mullins🇺🇸 · Mauricio Hippert🇺🇸 · Lorenzo Gavassino🇺🇸 · Jorge Noronha🇺🇸
Causality is necessary for retarded Green's functions to remain retarded in all inertial frames in relativity, which ensures that dissipation of fluctuations is a Lorentz invariant concept. For first-order BDNK theories with stochastic fluctuations, introduced via the Schwinger-Keldysh formalism, we show that imposing causality and stability leads to correlation functions of hydrodynamic fluctuations that only display the expected physical properties at small frequencies and wavenumber, i.e., within the expected regime of validity of the first-order approach. For second-order theories of Israel and Stewart type, constructed using the information current such that entropy production is always non-negative, a stochastic formulation is presented using the Martin-Siggia-Rose approach where imposing causality and stability leads to correlators with the desired properties. We also show how Green's functions can be determined from such an action. We identify a $Z_{2}$ symmetry, analogous to the Kubo-Martin-Schwinger symmetry, under which this Martin-Siggia-Rose action is invariant. This modified Kubo-Martin-Schwinger symmetry provides a new guide for the effective action formulation of hydrodynamic systems with dynamics not solely governed by conservation laws. Furthermore, this symmetry ensures that the principle of detailed balance is valid in a covariant manner. We employ the new symmetry to further clarify the connection between the Schwinger-Keldysh and Martin-Siggia-Rose approaches, establishing a precise link between these descriptions in second-order theories of relativistic hydrodynamics. Finally, the modified Kubo-Martin-Schwinger symmetry is used to determine the corresponding action describing diffusion in Israel-Stewart theories in a general hydrodynamic frame.
Comments:
28 pages
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2309.00512 [pdf]
PRD(2023)·31 citations

Affiliations

first authorsco-authorsvia INSPIRE

Semi-inclusive direct photon+jet and π0+jet correlations measured in p+p and central Au+Au collisions at sNN​​=200 GeV

Measurement of in-medium jet modification using direct photon+jet and π0+jet correlations in p+p and central Au+Au collisions at sNN​​=200 GeV

Correlation function for the Tbb​ state: Determination of the binding, scattering lengths, effective ranges and molecular probabilities

Schwinger-Keldysh effective field theory for stable and causal relativistic hydrodynamics

Relativistic hydrodynamic fluctuations from an effective action: causality, stability, and the information current

Affiliations

Semi-inclusive direct photon+jet and $π^{0}$ +jet correlations measured in $p + p$ and central Au+Au collisions at $s_{NN} = 200$ GeV

Measurement of in-medium jet modification using direct photon+jet and $π^{0}$ +jet correlations in $p + p$ and central Au+Au collisions at $s_{NN} = 200$ GeV

Correlation function for the $T_{bb}$ state: Determination of the binding, scattering lengths, effective ranges and molecular probabilities