Thu·Apr 9, 2015Thursday·April 9, 2015

1. 01*

   Overview of ALICE results on azimuthal correlations using neutral- and heavy-meson triggers

   Sona Pochybova (for the ALICE Collaboration)🇭🇺

   The ALICE detector is dedicated to studying the properties of hot and dense matter created in heavy-ion collisions. Among the probes used to investigate these properties are high-momentum particles, which originate in hard-scatterings occurring before the fireball creation. The fragments of hard scatterings interact with the hot and dense matter and via this interaction their spectra and azimuthal distributions are modified. This is probed by the measurement of the nuclear modification factor, where the $p_{\mathrm{T}}$ spectra obtained in Pb-Pb collisions are compared to a pp baseline. A strong suppression of charged hadrons as well as neutral- and heavy-flavor mesons was observed at $p_{\mathrm{T}}>4$ GeV/$c$. Azimuthal correlations, using high-momentum ($p_{\mathrm{T}}>4$ GeV/$c$) hadrons as triggers, can provide further insight into how the presence of the medium modifies the final kinematic distributions of the particles. Comparison with theoretical models can be used to test their predictions about the properties of the medium. We give an overview of ALICE azimuthal-correlation measurements of neutral- and heavy-flavor mesons with charged hadrons in pp collisions at $\sqrt{s}=7$ TeV and Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV. We also present a measurement of the ${\pi }^0$ correlation with jets in pp collisions at $\sqrt{s}=7$ TeV.

   ↳ hep-exnucl-exJ.Phys.Conf.Ser.(2017)·0 citations
2. 02*

   Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions

   H.S. Jo · F.X. Girod · H. Avakian · V.D. Burkert · M. Garçon · M. Guidal · V. Kubarovsky · S. Niccolai · P. Stoler · the CLAS Collaboration

   Unpolarized and beam-polarized four-fold cross sections $\frac{d^4\sigma }{d{Q}^{2}d{x}_{B}dtd\varphi }$ for the $ep\to e^{\prime }{p}^{\prime }\gamma$ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 ($Q^2,x_B,t$) bins over the widest phase space ever explored in the valence-quark region. Several models of Generalized Parton Distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD $H$, expected to be the dominant contributor to these observables. Through a leading-twist extraction of Compton Form Factors, these results reveal a tomographic image of the nucleon.

   ↳ hep-exnucl-exPRL(2015)·143 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.