Mon·Nov 3, 2014Monday·November 3, 2014

1. 01*

   Directional Antineutrino Detection

   Benjamin R. Safdi🇺🇸 · Burkhant Suerfu🇺🇸

   We propose the first truly directional antineutrino detector for antineutrinos above the hydrogen inverse beta decay (IBD) threshold, with potential applications including monitoring for nuclear nonproliferation, spatially mapping geo-neutrinos, characterizing the diffuse supernova neutrino background, and searching for new physics in the neutrino sector. The detector consists of adjacent and separated target and capture scintillator planes. IBD events take place in the target layers, which are thin enough to allow the neutrons to escape without scattering elastically. The neutrons are detected in the thicker, boron-loaded capture layers. The location of the IBD event and the momentum of the positron are determined by tracking the positron's trajectory through the detector. Our design is a straightforward modification of existing antineutrino detectors; a prototype could be built with existing technology.

   ↳ physics.ins-dethep-exhep-phnucl-ex+1PRL(2015)·11 citations
2. 02*

   Charge Symmetry Breaking in the Nucleon and Parity Violating Elastic Electron-Proton Scattering

   Gerald A. Miller🇺🇸

   The basic facts of charge symmetry breaking (CSB) phenomena are reviewed. The relevance of CSB to parity-violating electron-proton scattering experiments that seek to extract strange elastic form factors is discussed. Experimentalists have stated and written that the current uncertainty in our knowledge of CSB limits the ability to push further on the strange form factors. I discuss recent calculations using relativistic chiral perturbation theory and realistic values of strong coupling constants which show that the uncertainties due to lack of knowledge of CSB are at least ten times smaller than present experimental uncertainties. Estimates of CSB effects are made for the JLab Qweak and Mainz P2 experiments.

   ↳ nucl-thhep-phnucl-ex1 citation
3. 03*

   J/psi-Pair Production at Large Momenta: Indications for Double-Parton Scatterings and Large alpha_s^5 Contributions

   Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇨🇭

   We demonstrate that the recent studies of J/psi-pair production by CMS at the LHC and by D0 at the Tevatron reveal the presence of different production mechanisms in different kinematical regions. We find out that next-to-leading-order single parton scattering contributions at alpha_s^5 dominate the yield at large transverse momenta of the pair. Our analysis further emphasises the importance of double parton scatterings --which are expected to dominate the yield at large J/psi-rapidity differences-- at large invariant masses of the pair in the CMS acceptance, and thereby solve a large discrepancy between the theory and the CMS data. In addition, we provide the first exact --gauge-invariant and infrared-safe-- evaluation of a class of leading-P_T (P_T^-4) next-to-next-to-leading-order contributions at alpha_s^6, which can be relevant in the region of large values of P_T,min=min(P_T1,P_T2). Finally, we derive simple relations for the feed-down fractions from the production of an excited charmonium state with a J/psi in the case of the dominance of the double parton scatterings, which significantly deviate from those for single parton scatterings. Such relations can be used to discriminate these extreme scenari, either DPS or SPS dominance.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2015)·148 citations
4. 04*

   Sensitivity Increases for the TITAN Decay Spectroscopy Program

   K.G. Leach🇨🇦 · A. Lennarz🇨🇦 · A. Grossheim🇨🇦 · C. Andreoiu🇨🇦 · J. Dilling🇨🇦 · D. Frekers🇩🇪 · M. Good🇨🇦 · S. Seeraji🇨🇦

   The TITAN facility at TRIUMF has recently initiated a program of performing decay spectroscopy measurements in an electron-beam ion-trap (EBIT). The unique environment of the EBIT provides backing-free storage of the radioactive ions, while guiding charged decay particles from the trap centre via the strong magnetic field. This measurement technique is able to provide a significant increase in detection sensitivity for photons which result from radioactive decay. A brief overview of this device is presented, along with methods of improving the signal-to-background ratio for photon detection by reducing Compton scattered events, and eliminating vibrational noise.

   ↳ physics.ins-detnucl-exEPJ Web Conf.(2015)·5 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.