Wed·May 1, 2019Wednesday·May 1, 2019

1. 01*

   Measurement of jet radial profiles in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV

   ALICE Collaboration

   The jet radial structure and particle transverse momentum ($p_{\mathrm{T}}$) composition within jets are presented in centrality-selected Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV. Track-based jets, which are also called charged jets, were reconstructed with a resolution parameter of $R=0.3$ at midrapidity $|{\eta }_{\mathrm{ch}\mathrm{jet}}|<0.6$ for transverse momenta p_\rm{T,\,ch\,jet}=30-$120$ GeV/$c$. Jet-hadron correlations in relative azimuth and pseudorapidity space ($\Delta \phi$, $\Delta \eta$) are measured to study the distribution of the associated particles around the jet axis for different p_\rm{T, assoc}-ranges between 1 and 20 GeV/$c$. The data in Pb-Pb collisions are compared to reference distributions for pp collisions, obtained using embedded PYTHIA simulations. The number of high-$p_{\mathrm{T}}$ associate particles (4<p_\rm{T, assoc}<20 GeV/$c$) in Pb-Pb collisions is found to be suppressed compared to the reference by 30 to 10%, depending on centrality. The radial particle distribution relative to the jet axis shows a moderate modification in Pb-Pb collisions with respect to PYTHIA. High-$p_{\mathrm{T}}$ associate particles are slightly more collimated in Pb-Pb collisions compared to the reference, while low-$p_{\mathrm{T}}$ associate particle tend to be broadened. The results, which are presented for the first time down to p_\rm{T,\,ch\,jet}=30 GeV/$c$ in Pb-Pb collisions, are compatible with both previous jet-hadron-related measurements from the CMS Collaboration and jet shape measurements from the ALICE Collaboration at higher $p_{\mathrm{T}}$, and add further support for the established picture of in-medium parton energy loss.

   nucl-exhep-exPLB(2019)·22 citations
2. 02*

   Electric dipole moment searches using storage rings

   Frank Rathmann🇩🇪 · Nikolai N. Nikolaev🇷🇺

   The Standard Model (SM) of Particle Physics is not capable to account for the apparent matter-antimatter asymmetry of our Universe. Physics beyond the SM is required and is either probed by employing highest energies (e.g., at LHC), or by striving for ultimate precision and sensitivity (e.g., in the search for electric dipole moments). Permanent electric dipole moments (EDMs) of particles violate both time reversal $(T)$ and parity $(P)$ invariance, and are via the $CPT$-theorem also $CP$-violating. Finding an EDM would be a strong indication for physics beyond the SM, and pushing upper limits further provides crucial tests for any corresponding theo\-retical model, e.g., SUSY. Up to now, EDM searches focused on neutral systems (neutrons, atoms, and molecules). Storage rings, however, offer the possibility to measure EDMs of charged particles by observing the influence of the EDM on the spin motion in the ring. Direct searches of proton and deuteron EDMs, however, bear the potential to reach sensitivities beyond $10^{-29}$ e$\cdot$cm. Since the Cooler Synchrotron COSY at the Forschungszentrum Jülich provides polarized protons and deuterons up to momenta of 3.7 GeV/c, it constitutes an ideal testing ground and starting point for such an experimental program. Besides the discussion of the achievements of the JEDI collaboration, and the description of an effort to perform a first direct deuteron EDM measurement at COSY, the report highlights in addition future technical developments that will pave the way toward EDM searches in dedicated rings. A recent advancement that grew out of the successful work performed by JEDI is the formation of the CPEDM Collaboration, which aims at the design of an EDM prototype ring that could be hosted either at CERN or at COSY, will be discussed as well.

   nucl-exPoS(2019)·9 citations
3. 03*

   Mapping the Kinematical Regimes of Semi-Inclusive Deep Inelastic Scattering

   M. Boglione🇮🇹 · A. Dotson🇺🇸 · L. Gamberg🇺🇸 · S. Gordon🇺🇸 · J. O. Gonzalez-Hernandez🇮🇹 · A. Prokudin🇺🇸 · T. C. Rogers🇺🇸 · N. Sato🇺🇸

   We construct a language for identifying kinematical regions of transversely differential semi-inclusive deep inelastic scattering cross sections with particular underlying partonic pictures, especially in regions of moderate to low $Q$ where sensitivity to kinematical effects outside the usual very high energy limit becomes non-trivial. The partonic pictures map to power law expansions whose leading contributions ultimately lead to well-known QCD factorization theorems. We propose methods for estimating the consistency of any particular region of overall hadronic kinematics with the kinematics of a given underlying partonic picture. The basic setup of kinematics of semi-inclusive deep inelastic scattering is also reviewed in some detail.

   ↳ hep-phnucl-exnucl-thJHEP(2019)·54 citations
4. 04*

   Application of an ab-initio S-matrix to data analysis of transfer to the continuum reactions populating 11Be

   A. Bonaccorso🇮🇹 · F. Cappuzzello🇮🇹 · D. Carbone🇮🇹 · M. Cavallaro🇮🇹 · G. Hupin🇫🇷 · P. Navratil🇨🇦 · S. Quaglioni🇺🇸

   Recently, the bound and continuum spectrum of 11Be has been calculated within the ab-initio no-core shell model with continuum (NCSMC) method successfully reproducing the parity inversion in the ground state. The continuum spectrum obtained is in agreement with known experimental levels. The S-matrix contained in the NCSMC continuum wave functions of the n+10Be system is used in this work for the first time in a Transfer-to-the-Continuum (TC) reaction calculation. The TC approach is applied to study the excitation energy spectrum of 11Be measured in the 9Be(18O,16O)11Be reaction at 84 MeV. Previously known levels are confirmed and theoretical and experimental evidence for a 9/2+ state at Ex=5.8 MeV is given, whose configuration is thought to be 10Be(2+)+n(d5/2).

   ↳ nucl-thnucl-exPRC(2019)·15 citations
5. 05*

   Development of a neutron imaging station at the n\_TOF facility of CERN and applications to beam intercepting devices

   Federica Mingrone🇨🇭 · Marco Calviani🇨🇭 · Claudio Torregrosa Martin🇨🇭 · Oliver Aberle🇨🇭 · Michael Bacak🇨🇭 · Enrico Chiaveri🇨🇭 · Elvis Fornasiere🇨🇭 · Antonio Perillo-Marcone🇨🇭 · Vasilis Vlachoudis🇨🇭

   A neutron radiography testing station has been developed exploiting the neutron beam of CERN's n\_TOF Experimental Area 2, located at the shortest distance to the neutron producing-target. The characteristics of the n\_TOF neutron beam for the imaging setup are presented in this paper, together with the obtained experimental results. The possible developments of neutron imaging capabilities of the n\_TOF facility in terms of detection-systems and beam-line upgrades are as well outlined.

   ↳ physics.ins-dethep-exnucl-exInstruments(2019)·4 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.