An overview of the latest theoretical developments and results on electromagnetic and weak probes in relativistic heavy-ion collisions is presented. The possibilities to use electromagnetic probes, i.e., photons and dileptons, as a spectrometer, thermometer, chronometer, polarimeter, barometer, and multimeter of the collision system, as well as to explore the QCD phase diagram and to locate phase transitions such as the critical endpoint, are discussed.
Recent theoretical developments concerning radiation of electromagnetic and weak probes in ultra-relativistic heavy-ion collisions is overviewed. These proceedings focus on electromagnetic probes and briefly cover weak probes. An outlook regarding the future use of electromagnetic probes is formulated whereby a quantitative Bayesian comparison, simultaneously employing electromagnetic and hadronic calculations of experimental observables against data, is highlighted as a path towards a better understanding of the properties of the QCD medium.
The penetrating nature of electromagnetic probes makes them an ideal candidate to study properties of the Quark-Gluon Plasma (QGP). A selection of recent developments in the theory and phenomenology of electromagnetic probes is discussed, with an emphasis given towards how these probes can be used to constrain QGP trapnsport coefficients. A Bayesian treatment of electromagnetic radiation, similar to the one of soft hadronic observables and jets, is suggested as a path towards imposing more stringent constraints on various transport coefficients of the QCD medium.
The penetrating nature of electromagnetic signals makes them suitable probes to explore the properties of the strongly-interacting medium created in relativistic nuclear collisions. We examine the effects of the initial conditions and shear relaxation time on the spectra and flow coefficients of electromagnetic probes, using an event-by-event 3+1D viscous hydrodynamic simulation (MUSIC).
An overview is given of the theoretical developments on heavy quarks and quarkonia in heavy-ion collisions as reported at the "Hard and EM Probes 2018" conference. Specifically, we address progress in the understanding of heavy-flavor diffusion and its hadronization, quarkonium transport and the extraction of quarkonium melting temperatures, energy loss of heavy quarks at high momentum, and their rescattering in small colliding systems.
After a brief reminder on the electromagnetic properties of neutrinos, the main processes of the electromagnetic interactions of neutrinos in astrophysics and the corresponding limitations on millicharges and effective magnetic moments of the particle are discussed.
The use of light front coordinates allows a fully relativistic description of a hadron's spatial densities to be obtained. These densities must be two-dimensional and transverse to a chosen spatial direction. We explore their relationship to the three-dimensional, non-relativistic densities, with a focus on densities associated with the energy momentum tensor. The two-dimensional non-relativistic densities can be obtained from the light front densities through a non-relativistic limit, and can subsequently be transformed into three-dimensional non-relativistic densities through an inverse Abel…
We study the electromagnetic contribution to elastic neutrino-proton and neutrino-neutron scattering processes. The neutrino electromagnetic charge, magnetic, electric, and anapole form factors of both diagonal and transition types in the mass basis are taken into account in the present formalism. When treating the nucleon electromagnetic vertex, we take into account not only the charge and magnetic form factors of a nucleon, but also its electric and anapole form factors. We examine how the effects of the neutrino magnetic moment can be disentangled from those of the strange quark contributio…
We investigate the $P_T$-broadening effects in dilepton production through photon-photon scattering in heavy ion collisions. The QED multiple interaction effects with the medium is found to be consistent with a recent observation of low transverse momentum lepton pair from ATLAS collaboration at the LHC. We further comment on the magnetic effects and point out a number of ways to disentangle these two mechanisms. In particular, the rapidity dependence of the $P_T$-broadening effects provide a unique probe to the magnetic effects.
In this contribution, we discuss the electromagnetic and weak decays of baryons in the unquenched quark model and show that the observed discrepancies between the experimental data and the predictions of the constituent quark model can be accounted for in large part by the effects of sea quarks. Finally, the obtained results are discussed in terms of flavor-symmetry breaking.
Photon Colliders in Physical Program for Large Colliders. Talk given at Workshop on Electromagnetic Probes of Fundamental Physics, Eriche, Sicily, 16-21 October 2001
Electromagnetic probes of concurrent minijet-hydrodynamics evolution
National Institute of Science Education and Research（印度科学教育研究所）；Homi Bhabha National Institute（霍米·巴巴国立研究所）；Vanderbilt University（范德堡大学）；McGill University（麦吉尔大学）；Universidad de Oviedo（奥维耶多大学）；Instituto Universitario de Ciencias y Tecnologías Espaciales de Asturias (ICTEA)（阿斯图里亚斯空间科学与技术大学研究所）
Recent theory developments in electromagnetic radiation from relativistic heavy-ion collisions are reviewed. Electromagnetic observables can serve as a thermometer, a viscometer, and tomographic probes to the collision system. The current status of the "direct photon flow puzzle" is highlighted.
We review the current state of research on electromagnetic probes in the context of heavy-ion collisions. The focus is on thermal photons and dileptons which provide unique insights into the properties of the created hot and dense matter. This review is intended to provide an introductory overview of the topic as well as a discussion of recent theoretical and experimental results. In particular, we discuss the role of vector-meson spectral functions in the calculation of photon and dilepton rates and present recent results obtained from different frameworks. Furthermore, we will highlight the …
Search for electromagnetic properties of the neutrinos at the LHC
通过光子-光子聚变产生的中微子为在LHC上探测中微子的电磁性质提供了一个极好的机会。我们探讨了pp-> p gamma p -> p nu anti-nu p和pp -> p gamma p -> p nu anti-nu Z p过程探测中微子-光子和中微子-双光子耦合的可能性。我们发现，这些反应提供了超过7个数量级的改善中微子双光子耦合相比，LEP限制。
In this work, a compilation of effective electromagnetic field couplings to pions and constituent quarks and their effective interactions derived previously, including corrections to the NJL model, is presented. The particular case of a weak external magnetic field along the $\hat{z}$ direction is considered shortly and effective coupling constants are redefined to incorporate the weak-$B_0$ dependence. They correspond to corrections to well known pion-constituent quark couplings and to the NJL and vector NJL effective couplings that break isospin and chiral symmetries.
Study of the electromagnetic transitions $J/ψ\rightarrow P l^+l^-$ and probe dark photon
我们研究了$J/ψ\rightarrow P l^+l^-$（$P= π^0$，$η$或$η^\prime$）的电磁Dalitz衰变模式.在这些衰变中，轻子对是由具有不变质量$m_{l^+l^-}$的中间虚光子的内部转换形成的。对$l^+l^-$有效质谱的研究将揭示动态跃迁形状因子$F_{J/ψP}(q^2)$（$q^2 = m^2_{l^+l^-}$），它表征了$J/ψ$向赝标量跃迁顶点处产生的电磁结构.我们还讨论了GeV尺度矢量$U$玻色子在这些过程$J/ψ\rightarrow PU$（$U\rightarrow l^+l^-$）中的直接产生。它是负责调解一个新的$U(1)_d$相互作用，最近在弱相互作用的大质量粒子暗物质的背景下利用。本文首先利用通常的形状因子的极点近似估计了标准模型中$J/ψ\rightarrow P l^+l^-$的衰减率。估计了暗光子的搜索范围。我们认为，这些Dalitz衰变可以用来寻找轻$U$玻色子在BESIII实验与一个巨大的$J/ψ$数据集。
Electromagnetic probes as signatures for a first-order QCD phase transition
University of Malaya（马来亚大学）；GSI Helmholtzzentrum für Schwerionenforschung GmbH（GSI亥姆霍兹重离子研究中心有限公司）；Frankfurt Institute for Advanced Studies（法兰克福高级研究所）；Johann Wolfgang Goethe-Universität（约翰·沃尔夫冈·歌德大学）；Helmholtz Research Academy Hessen for FAIR (HFHF)（黑森亥姆霍兹FAIR研究院）；Suranaree University of Technology（素拉那瑞理工大学）
Impact of the in-medium modified nucleon weak and electromagnetic form factors on the neutrino mean free path in dense matter is studied by considering both the weak and electromagnetic interactions of neutrinos with the constituents of the matter. A relativistic mean field model and the quark-meson coupling model are respectively adopted for the in-medium effective nucleon mass and nucleon form factors. We find that the cross sections of neutrino scattering in cold nuclear medium decreases when the in-medium modification of the nucleon weak and electromagnetic form factors are taken into acco…
A particle, which moves in a crystal, experiences weak interactions with electrons and nuclei alongside with electromagnetic interaction. Measuring the polarization vector and the angular distribution of charged and neutral particles scattered by axes (planes) of an unbent (straight) crystal enables to obtain restrictions for the EDM value and for {magnitudes} of constants describing T-odd (CP-odd) interactions Beyond the Standard Model. Spin rotation and polarization conversion from vector to tensor one and vice versa for a channelled in a crystal $Ω^{\pm}$ hyperon enable measuring hyperon's …
