Mon·Jan 30, 2017Monday·January 30, 2017

1. 01*

   Measurement of the beam asymmetry $\Sigma$ for ${\pi }^0$ and $\eta$ photoproduction on the proton at $E_{\gamma }=9$ GeV

   GlueX Collaboration: H. Al Ghoul🇺🇸 · E. G. Anassontzis🇬🇷 · A. Austregesilo🇺🇸 · F. Barbosa🇺🇸 · A. Barnes🇺🇸 · T. D. Beattie🇨🇦 · D. W. Bennett🇺🇸 · V. V. Berdnikov🇷🇺 · T. Black🇺🇸 · W. Boeglin🇺🇸 · W. J. Briscoe🇺🇸 · W. K. Brooks🇨🇱 and 113 other authors

   We report measurements of the photon beam asymmetry $\Sigma$ for the reactions $\vec{\gamma }p\to p{\pi }^0$ and $\vec{\gamma }p\to p\eta$ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous ${\pi }^0$ measurements and are the first $\eta$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models.

   nucl-exPRC(2017)·85 citations
2. 02*

   Full jet in quark-gluon plasma with hydrodynamic medium response

   Yasuki Tachibana🇨🇳 · Ning-Bo Chang🇨🇳 · Guang-You Qin🇨🇳

   We study the nuclear modifications of full jets and their structures in relativistic heavy-ion collisions including the effect of hydrodynamic medium response to jet quenching. To study the evolutions of the full jet shower and the traversed medium with energy and momentum exchanges between them, we formulate a coupled jet-fluid model consisting of a set of jet transport equations and relativistic hydrodynamics equations with source terms. In our model, the full jet shower interacts with the medium and gets modified via collisional and radiative processes during the propagation. Meanwhile, the energy and momentum are deposited from the jet shower to the medium and then evolve with the medium hydrodynamically. The full jet defined by a cone size in the final state includes the jet shower and the particles produced from jet-induced flow. We apply our model to calculate the full jet energy loss and the nuclear modifications of jet rate and shape in Pb+Pb collisions at $2.76\mathrm{A}\mathrm{TeV}$. It is found that the inclusion of jet-induced flow contribution leads to stronger jet-cone size dependence for jet energy loss and jet suppression. Jet-induced flow also has a significant contribution to jet shape function and dominates at large angles away from the jet axis.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2017)·164 citations
3. 03*

   Top-quark and Higgs boson perspectives at heavy-ion colliders

   David d'Enterria🇨🇭

   The perspectives for measuring the top quark and the Higgs boson in nuclear collisions at the LHC and Future Circular Collider (FCC) are summarized. Perturbative QCD calculations at (N)NLO accuracy, including nuclear parton distribution functions, are used to determine their cross sections and visible yields after standard analysis cuts in PbPb and pPb collisions at the LHC ($\sqrt{s_{NN}}$ = 5.5, 8.8 TeV) and FCC ($\sqrt{s_{NN}}$ = 39, 63 TeV). In their "cleanest" decay channels, $\mathrm{t}\bar{\mathrm{t}}\to \mathrm{b}\bar{\mathrm{b}}2\mathrm{\ell }2\nu$ and $\mathrm{H}\to \gamma \gamma ,4\mathrm{\ell }$, about 10${}^3$ ($10^5$) top-quark and 10 (10${}^3$) Higgs-boson events are expected at the LHC (FCC) for their total nominal integrated luminosities. Whereas the $\mathrm{t}\bar{\mathrm{t}}$ observation is clearcut at both colliders, evidence for Higgs production, perfectly possible at the FCC, requires integrating $\times$30 more luminosities at the LHC.

   ↳ hep-exhep-phnucl-exnucl-thNucl.Part.Phys.Proc.(2017)·18 citations
4. 04*

   Deconvolution of the energy loss function of the KATRIN experiment

   Volker Hannen🇩🇪 · Irina Heese🇩🇪 · Anna Sejersen Riis🇩🇰 · Kathrin Valerius🇩🇪 · Christian Weinheimer🇩🇪

   The KATRIN experiment aims at a direct and model independent determination of the neutrino mass with 0.2 eV/c^2 sensitivity (at 90% C.L.) via a measurement of the endpoint region of the tritium beta-decay spectrum. The main components of the experiment are a windowless gaseous tritium source (WGTS), differential and cryogenic pumping sections and a tandem of a pre- and a main-spectrometer, applying the concept of magnetic adiabatic collimation with an electrostatic retardation potential to analyze the energy of beta decay electrons and to guide electrons passing the filter onto a segmented silicon PIN detector. One of the important systematic uncertainties of such an experiment are due to energy losses of beta-decay electrons by elastic and inelastic scattering off tritium molecules within the source volume which alter the shape of the measured spectrum. To correct for these effects an independent measurement of the corresponding energy loss function is required. In this work we describe a deconvolution method to extract the energy loss function from measurements of the response function of the experiment at different column densities of the WGTS using a monoenergetic electron source.

   ↳ physics.ins-detnucl-exAstropart.Phys.(2017)·12 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.