Thu·Oct 26, 2017Thursday·October 26, 2017

1. 01*

   Vorticity and particle polarization in heavy ion collisions (experimental perspective)

   Sergei A. Voloshin🇺🇸

   The recent measurements of the global polarization and vector meson spin alignment along the system orbital momentum in heavy ion collisions are briefly reviewed. A possible connection between the global polarization and the chiral anomalous effects is discussed along with possible experimental checks. Future directions, in particular those aimed on the detailed mapping of the vorticity fields, are outlined. The Blast Wave model is used for an estimate of the anisotropic flow effect on the vorticity component along the beam direction. We also point to a possibility of a circular pattern in the vorticity field in asymmetric, e.g. Cu+Au, central collisions.

   nucl-exEPJ Web Conf.(2018)·77 citations
2. 02*

   The connection between zero chromaticity and long in-plane polarization lifetime in a magnetic storage ring

   G. Guidoboni · E.J. Stephenson · A Wrońska · Z. Bagdasarian · J. Bsaisou · S. Chekmenev · S. Dymov · D. Eversmann · M. Gaisser · R. Gebel · V. Hejny · N. Hempelmann and 31 other authors

   In this paper, we demonstrate the connection between a magnetic storage ring with additional sextupole fields set so that the x and y chromaticities vanish and the maximizing of the lifetime of in-plane polarization (IPP) for a 0.97-GeV/c deuteron beam. The IPP magnitude was measured by continuously monitoring the down-up scattering asymmetry (sensitive to sideways polarization) in an in-beam, carbon-target polarimeter and unfolding the precession of the IPP due to the magnetic anomaly of the deuteron. The optimum operating conditions for a long IPP lifetime were made by scanning the field of the storage ring sextupole magnet families while observing the rate of IPP loss during storage of the beam. The beam was bunched and electron cooled. The IPP losses appear to arise from the change of the orbit circumference, and consequently the particle speed and spin tune, due to the transverse betatron oscillations of individual particles in the beam. The effects of these changes are canceled by an appropriate sextupole field setting.

   ↳ physics.acc-phnucl-exphysics.ins-detPhys.Rev.Accel.Beams(2018)·32 citations
3. 03*

   Status of COMPASS RICH-1 Upgrade with MPGD-based Photon Detectors

   M. Alexeev🇮🇹 · R Birsa🇮🇹 · F. Bradamante🇮🇹 · A. Bressan🇮🇹 · M. Chiosso🇮🇹 · P. Ciliberti🇮🇹 · S. Dalla Torre🇮🇹 · S. Dasgupta🇮🇹 · O. Denisov🇮🇹 · M. Finger · M. Finger Jr · H. Fishcher🇩🇪 and 23 other authors

   A Set of new MPGD-based Photon Detectors is being built for the upgrade of COMPASS RICH-1. The detectors cover a total active area of 1.4 m${}^2$ and are based on a hybrid architecture consisting of two THGEM layers and a Micromegas. A CsI film on one THGEM acts as a reflective photocathode. The characteristics of the detector, the production of the components and their validation tests are described in detail.

   ↳ physics.ins-dethep-exnucl-exEPJ Web Conf.(2018)·3 citations
4. 04*

   Phenomenology of neutron-antineutron conversion

   Susan Gardner🇺🇸 · Xinshuai Yan🇺🇸

   We consider the possibility of neutron-antineutron ($n-\bar{n}$) conversion, in which the change of a neutron into an antineutron is mediated by an external source, as can occur in a scattering process. We develop the connections between $n-\bar{n}$ conversion and $n-\bar{n}$ oscillation, in which a neutron spontaneously tranforms into an antineutron, noting that if $n-\bar{n}$ oscillation occurs in a theory with B-L violation, then $n-\bar{n}$ conversion can occur also. We show how an experimental limit on $n-\bar{n}$ conversion could connect concretely to a limit on $n-\bar{n}$ oscillation, and vice versa, using effective field theory techniques and baryon matrix elements computed in the M.I.T. bag model.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2018)·15 citations
5. 05*

   Evolution and Recent Developments of the Gaseous Photon Detectors Technologies

   Fulvio Tessarotto🇮🇹

   The evolution and the present status of the gaseous photon detectors technologies are reviewed. The most recent developments in several branches of the field are described, in particular the installation and commissioning of the first large area MPGD-based detectors of single photons on COMPASS RICH-1. Investigation of novel detector architectures, different materials and various applications are reported, and the quest for visible light gaseous photon detectors is discussed. The progress on the use of gaseous photon detector related techniques in the field of cryogenic applications and gaseous or liquid scintillation imaging are presented.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2018)·7 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.