Related papers: Pion Imaging at the AGS
In these proceedings, we present the measurements of charged $K^{+} - K^{+}$ and neutral $K_{s}^{0} - K_{s}^{0}$ correlation functions from Au+Au fixed-target collisions at $\sqrt{s_{NN}}$ = 3.0, 3.2, 3.5, 3.9 and 4.5 GeV at STAR. This is…
Recently, the ALICE collaboration analyzed the three- and four-pion Hanbury Brown-Twiss (HBT) correlations in Pb-Pb collisions at the Large Hadron Collider (LHC). The measured suppressions of three- and four-pion correlations may originate…
The space-averaged phase-space density and entropy per particle are both fundamental observables which can be extracted from the two-particle correlation functions measured in heavy-ion collisions. Two techniques have been proposed to…
Pion photoproduction reactions are investigated in a dynamical coupled-channel approach based on the Juelich pi-N model, which presently includes the hadronic pi-N and eta-N stable channels as well as the pi-Delta, sigma-N and rho-N…
The quasifree $\overrightarrow{\gamma} d\to\pi^0n(p)$ photon beam asymmetry, $\Sigma$, has been measured at photon energies, $E_\gamma$, from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first…
We calculate the two-pion correlation function for an expanding hadron source with a finite baryon density. The space-time evolution of the source is described by relativistic hydrodynamics and the Hanbury-Brown-Twiss (HBT) radius is…
We present high-statistic data on charged pion emission from Au+Au collisions at $\sqrt{s_{\rm{NN}}}$ = 2.4 GeV (corresponding to $E_{beam}$ = 1.23 A GeV) in four centrality classes in the range 0 - 40$\%$ of the most central collisions.…
Over the past few decades, progress in femtoscopy has been driven by the interplay between experimental measurements and theoretical calculations. Measurements provide data to support the theory, while theoretical predictions guide new…
Bose-Einstein correlations of identically charged pion pairs were measured by the PHENIX experiment at mid-rapidity in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV. The Bertsch-Pratt radius parameters were determined as a function of…
The mass distributions of baryon resonances populated in near-central collisions of Au on Au and Ni on Ni are deduced by defolding the $p_t$ spectra of charged pions by a method which does not depend on a specific resonance shape. In…
The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified charged pion pairs in Au+Au…
The current status of the analysis of direct photon Bose-Einstein correlations in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV done by the PHENIX collaboration is summarized. All possible sources of distortion of the two-photon correlation…
The measurement of the direct-photon spectrum from Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV is presented by the PHENIX collaboration using the external-photon-conversion technique for 0\%--93\% central collisions in a…
A Regge model with absorptive corrections is employed in a global analysis of the world data on positive and negative pion photoproduction for photon energies from 3 to 8 GeV. In this region resonance contributions are expected to be…
Measurement of femtoscopic correlations in heavy-ion collisions can provide information about spatial and temporal parameters of the particle emission region at kinetic freeze-out. In this work we present the measurement of two-pion and…
The leading-twist wave functions of the pion and the photon at a low normalization point are calculated in the effective low--energy theory derived from the instanton vacuum. The pion wave function is found to be close to the asymptotic…
Femtoscopy of non-central heavy ion collisions provides access to information on the geometry of the effective pion-emitting source. In particular, the source shape can be studied by measuring femtoscopic radii as a function of the pion…
The photoproduction of pion off nucleon is investigated within a dynamical coupled-channels approach based on the Juelich pi-N model, which has been quite successful in the description of pi-N to pi-N scattering for center-of-mass energies…
The STAR Collaboration at RHIC has measured two-pion correlation functions from p+p collisions at sqrt(s)=200 GeV. Spatial scales are extracted via a femtoscopic analysis of the correlations, though this analysis is complicated by the…
We report the measurement of direct photons at midrapidity in Au+Au collisions at sqrt{s_NN} = 200 GeV. The direct photon signal was extracted for the transverse-momentum range of 4 GeV/c < p_T < 22 GeV/c, using a statistical method to…