Mon·Oct 30, 2017Monday·October 30, 2017

1. 01*

   Abrupt phase change of the core rotation in the 143 Sm nucleus

   S. Rajbanshi · R. Raut🇮🇳 · H. Pai🇮🇳 · Sajad Ali🇮🇳 · A. Goswami🇩🇪 · G. Gangopadhyay🇮🇳 · S. Bhattacharyya🇮🇳 · G. Mukherjee🇮🇳 · S. Muralithar🇮🇳 · R. P. Singh🇮🇳 · M. Kumar Raju🇯🇵 · P. Singh🇫🇷 · R. K. Bhowmik🇮🇳

   Dipole sequences in the 143 Sm nucleus have been investigated via the 124 Sn ( 24 Mg, 5n) reaction at E lab = 107 MeV using the Indian National Gamma Array (INGA). The spin-parity of the associated levels have been firmly established from the spectroscopic measurement. Level lifetimes of several levels in the dipole bands have been measured using the Doppler Shift Attenuation Method. The decreasing trend of the measured B(M1) and B(E2) transition strengths in one of the sequence (DB I) spells out its origin as Magnetic Rotation (MR). The trends of B(M1) and B(E2) in DB I are reproduced well in the theoretical calculations using the Shears mechanism with the Principal Axis Cranking (SPAC) model. However, the calculations fail to reproduce the sharp rise in the B(M1)/B(E2) ratio at the highest spins in DB I and the same has been interpreted from the decreasing of the core rotation along the sequence. The experimental observations along with the the theoretical calculations for the second dipole band (DB II), indicate that the core rotation, rather than the shears mechanism, is being favored for angular momentum generation. This represents a unique observation of forking of the shears band DB I from an abrupt phase change of the core from spherical into the deformed one.

   nucl-exPLB(2018)·14 citations
2. 02*

   A data acquisition system based on ROOT and waveform digital technology for Photo-Neutron Source

   L.X. Liu · H.W. Wang🇨🇳 · Y.G. Ma🇨🇳 · X.G. Cao🇨🇳 · X.Z. Cai🇨🇳 · J.G. Chen🇨🇳 · G.L. Zhang · J.L. Han🇨🇳 · J.F. Hu🇨🇳 · X.H. Wang🇨🇳 · H.J. Fu🇨🇳

   The data acquisition system is based on ROOT and waveform digital technology, including neutron detector, waveform digitizer, PCI card, optical fiber, computer, reaction target device, stepper motor, data acquisition software and control target software. It achieves to acquire and record the waveform information of signal measured by the detector using a waveform digitizer. The specific target position is changed by the stepper motor which is remotely controlled by the data acquisition software and control target software. It is implemented by the exchange of information between the data acquisition software and the control target software. The system realizes to automatically open files and change targets at fixed intervals. It is capable of data compression by removing the data those are not signals, and automatic alarm when the beam is lost.

   ↳ physics.ins-detnucl-ex0 citations
3. 03*

   Color dipole predictions for the exclusive vector meson photoproduction in $pp/pPb/PbPb$ collisions at Run 2 LHC energies

   V. P. Goncalves🇧🇷 · M.V.T. Machado🇧🇷 · B. D. Moreira🇧🇷 · F. S. Navarra🇧🇷 · G. Sampaio dos Santos🇧🇷

   In this paper we present a comprehensive analysis of exclusive vector meson photoproduction in $pp$, $pPb$ and $PbPb$ collisions at Run 2 LHC energies using the Color Dipole formalism. The rapidity distributions and total cross sections for the $\rho$, $\varphi$, $J/\Psi$, $\Psi (2S)$ and ${\rm Y}$ production are estimated considering the more recent phenomenological models for the dipole - proton scattering amplitude, which are based on the Color Glass Condensate formalism and are able to describe the inclusive and exclusive $ep$ HERA data. Moreover, we also discuss the impact of the modelling of the vector meson wave functions on the predictions. The current theoretical uncertainty in the Color Dipole predictions is estimated and a comparison with the experimental results is performed.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2017)·93 citations
4. 04*

   Transverse spin-dependent azimuthal correlations of charged pion pairs measured in p${}^{\uparrow }$+p collisions at $\sqrt{s}$ = 500 GeV

   STAR Collaboration: L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · N. N. Ajitanand · I. Alekseev · D. M. Anderson · R. Aoyama · A. Aparin · D. Arkhipkin and 340 other authors

   The transversity distribution, which describes transversely polarized quarks in transversely polarized nucleons, is a fundamental component of the spin structure of the nucleon, and is only loosely constrained by global fits to existing semi-inclusive deep inelastic scattering (SIDIS) data. In transversely polarized $p^{\uparrow }+p$ collisions it can be accessed using transverse polarization dependent fragmentation functions which give rise to azimuthal correlations between the polarization of the struck parton and the final state scalar mesons. This letter reports on spin dependent di-hadron correlations measured by the STAR experiment. The new dataset corresponds to 25 pb${}^{-1}$ integrated luminosity of $p^{\uparrow }+p$ collisions at $\sqrt{s}=500$ GeV, an increase of more than a factor of ten compared to our previous measurement at $\sqrt{s}=200$ GeV. Non-zero asymmetries sensitive to transversity are observed at a $Q^2$ of several hundred GeV and are found to be consistent with the former measurement and a model calculation. %we observe consistent with the former measurement are observed.} We expect that these data will enable an extraction of transversity with comparable precision to current SIDIS datasets but at much higher momentum transfers where subleading effects are suppressed.

   ↳ hep-exnucl-exPLB(2018)·38 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.