Thu·Sep 29, 2011Thursday·September 29, 2011

1. 01*

   Upper Limit on the molecular resonance strengths in the ${}^{12}$C+${}^{12}$C fusion reaction

   X. Tang🇺🇸 · X. Fang🇺🇸 · B. Bucher🇺🇸 · H. Esbensen🇺🇸 · C. L. Jiang🇺🇸 · K. E. Rehm🇺🇸 · C. J. Lin🇨🇳

   Carbon burning is a crucial process for a number of important astrophysical scenarios. The lowest measured energy is around E${}_{c.m.}$=2.1 MeV, only partially overlapping with the energy range of astrophysical interest. The currently adopted reaction rates are based on an extrapolation which is highly uncertain because of potential resonances existing in the unmeasured energy range and the complication of the effective nuclear potential. By comparing the cross sections of the three carbon isotope fusion reactions, ${}^{12}$C+${}^{12}$C, ${}^{12}$C+${}^{13}$C and ${}^{13}$C+${}^{13}$C, we have established an upper limit on the molecular resonance strengths in ${}^{12}$C+${}^{12}$C fusion reaction. The preliminary results are presented and the impact on nuclear astrophysics is discussed.

   nucl-exastro-ph.SRnucl-thEPJ Web Conf.(2011)·3 citations
2. 02*

   Measurement of $\beta \beta$ Decay-Simulating Events in Nuclear Emulsion with Molybdenum Filling

   V.D. Ashitkov🇷🇺 · A.S. Barabash🇷🇺 · V.Ya. Bradnova🇷🇺 · V.A. Ditlov🇷🇺 · V.V. Dubinina🇷🇺 · N.P. Egorenkova🇷🇺 · S.I. Konovalov🇷🇺 · E.A. Pozharova🇷🇺 · N.G. Polukhina🇷🇺 · V.A. Smirnitsky🇷🇺 · N.I. Starkov🇷🇺 · M.M. Chernyavsky🇷🇺 · T.V. Shchedrina🇷🇺 · V.I. Umatov🇷🇺

   The measurement of positron--nucleus collisions was used to estimate the possibility of suppressing background events that simulate $\beta \beta$ decay in the emulsion region adjacent to molybdenum conglomerates. The range of the escape of two relativistic particles from the interaction was found to be $<d>=(0.60\pm 0.03)\mu$m, which approximately corresponds to the grain size of developed nuclear emulsion. No correlation of the values of d with the angle between two relativistic particles was observed. It was shown that it was possible to exclude $\beta \beta$ decay background from electrons emerging in the decay of elements of naturally occurring radioactive chains. The background from $\beta$ decays of ${}^{90}$Sr and ${}^{40}$K available in emulsion around Mo conglomerates was determined by the ratio of the volume $(\sim d^3)$ to the total volume of emulsion and was found to be $1.5\cdot 10^{-2}$. It was shown that the backgrounds from ${}^{40}$K, ${}^{90}$Sr and natural radioactivity could be significantly suppressed and would not limit the sensitivity of the experiment with 1 kg ${}^{100}$Mo.

   nucl-ex0 citations
3. 03*

   In-Medium Energy Loss and Correlations in Pb-Pb Collisions at sqrt(s_NN) = 2.76 TeV

   Jan Fiete Grosse-Oetringhaus (for the ALICE collaboration)🇨🇭

   ALICE (A Large Ion Collider Experiment) is the dedicated heavy-ion experiment at the LHC. In fall 2010, Pb-Pb collisions were recorded at a center-of-mass energy of 2.76 TeV per nucleon pair, about 14 times higher than the energy achieved in A-A collisions at RHIC. The study of the produced hot and dense matter with an unprecedented energy density allows the characterization of the quark-gluon plasma, the deconfined state of quarks and gluons, predicted by QCD. The study of in-medium partonic energy loss allows insights into the density of the medium and the energy-loss mechanisms. This paper presents results based on inclusive spectra as well as two and more-particle correlations of charged particles. These are well suited to assess in-medium effects, ranging from the suppression of particles (R_AA) and away-side jets (I_AA) at high pT to long-range phenomena attributed to collective effects like the ridge at low pT. The analysis is discussed and the results are presented in the context of earlier RHIC measurements where appropriate.

   nucl-exhep-exAIP Conf.Proc.(2012)·2 citations
4. 04*

   Search for Sterile Neutrinos with a Radioactive Source at Daya Bay

   D.A. Dwyer🇺🇸 · K.M. Heeger🇺🇸 · B.R. Littlejohn🇺🇸 · P. Vogel🇺🇸

   The far site detector complex of the Daya Bay reactor experiment is proposed as a location to search for sterile neutrinos with > eV mass. Antineutrinos from a 500 kCi 144Ce-144Pr beta-decay source (DeltaQ=2.996 MeV) would be detected by four identical 20-ton antineutrino targets. The site layout allows flexible source placement; several specific source locations are discussed. In one year, the 3+1 sterile neutrino hypothesis can be tested at essentially the full suggested range of the parameters Delta m^2_{new} and sin^22theta_{new} (90% C.L.). The backgrounds from six nuclear reactors at >1.6 km distance are shown to be manageable. Advantages of performing the experiment at the Daya Bay far site are described.

   ↳ hep-exnucl-exPRD(2013)·38 citations
5. 05*

   Extracting a free neutron structure function from proton and deuteron deep inelastic scattering data

   O. Hen🇮🇱 · E. Piasetzky🇮🇱 · R. Shneor🇮🇱 · L. B. Weinstein🇺🇸 · D. W. Higinbotham🇺🇸

   Due to the lack of a free neutron target the structure function of the neutron cannot be measured directly and is therefore extracted from deuteron and proton DIS data. Because the deuteron is a bound nuclear system, in order to extract the neutron structure function, one needs to apply model dependent theoretical corrections which dominate the uncertainty at the large xB region. We present here a correlation between the magnitude of the EMC effect and the amount of two nucleon Short Range Correlation (2N-SRC) pairs in nuclei. Using this correlation we propose a phenomenological procedure to extract the free neutron structure function in the xB range of 0.3 to 0.7.

   ↳ hep-phnucl-exnucl-th3 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.