Search results for "nuclear physics"
showing 10 items of 5307 documents
XENON100 dark matter results from a combination of 477 live days
2016
We report on WIMP search results of the XENON100 experiment, combining three runs summing up to 477 live days from January 2010 to January 2014. Data from the first two runs were already published. A blind analysis was applied to the last run recorded between April 2013 and January 2014 prior to combining the results. The ultra-low electromagnetic background of the experiment, ~$5 \times 10^{-3}$ events/(keV$_{\mathrm{ee}}\times$kg$\times$day) before electronic recoil rejection, together with the increased exposure of 48 kg $\times$ yr improves the sensitivity. A profile likelihood analysis using an energy range of (6.6 - 43.3) keV$_{\mathrm{nr}}$ sets a limit on the elastic, spin-independe…
Polarization of τ in quasielastic (anti)neutrino scattering: The role of spectral functions
2019
We present a study of the $\tau$ polarization in charged-current quasielastic (anti)neutrino-nucleus scattering. The spectral function formalism is used to compute the differential cross section and the polarization components for several kinematical setups, relevant for neutrino-oscillation experiments. The effects of the nuclear corrections in these observables are investigated by comparing the results obtained using two different realistic spectral functions, with those deduced from the relativistic global Fermi gas model, where only statistical correlations are accounted for. We show that the spectral functions, although they play an important role when predicting the differential cross…
Meson exchange currents in pion double charge exchange at high energies
1995
In this letter we study the high energy behavior of the forward differential cross section for the $^{18}O(\pi^+,\pi^-)^{18}Ne$ double charge exchange reaction. We have evaluated the sequential and the meson exchange current mechanisms. The meson exchange current contribution shows a very weak energy dependence and becomes relevant at incident pion kinetic energies above 600 MeV.
Measurement ofΥ(1S+2S+3S)production inp+pand Au + Au collisions atsNN=200GeV
2015
Measurements of bottomonium production in heavy-ion and p + p collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The inclusive yield of the three states, (1S + 2S + 3S), was measured in the PHENIX experiment via electron-positron decay pairs at midrapidity for Au + Au and p + p collisions at root sNN = 200 GeV. The (1S + 2S + 3S) -> e(+)e(-) differential cross section at midrapidity was found to be B(ee)d sigma/dy = 108 +/- 38 (stat) +/- 15 (syst) +/- 11 (luminosity) pb in p + p collisions. The nuclear modification factor in the 30% most central Au + Au collisions indicates a suppression of the total. state yield relative to the extrapolation from p + p collision data. …
Soft-gluon resummation for boosted top-quark production at hadron colliders
2012
We investigate the production of highly energetic top-quark pairs at hadron colliders, focusing on the case where the invariant mass of the pair is much larger than the mass of the top quark. In particular, we set up a factorization formalism appropriate for describing the differential partonic cross section in the double soft and small-mass limit, and explain how to resum simultaneously logarithmic corrections arising from soft gluon emission and from the ratio of the pair-invariant mass to that of the top quark to next-to-next-to-leading logarithmic accuracy. We explore the implications of our results on approximate next-to-next-to-leading order formulas for the differential cross section…
Final State Interaction Effects in Incoherent Pion Photoproduction on the Deuteron
2003
In the present work [1] incoherent photoproduction of pions on the deuteron in the Δ(1232) resonance region is investigated where besides the impulse approximation (IA) complete two-body rescattering in the nucleon-nucleon (NN) and pion-nucleon (πN) final state subsystems is included (see Fig. 1). The elementary γN → πN amplitude including Born and Δ(1232) resonance contributions is taken from previous work of [2].
Heavy-Flavor Contribution to Bhabha Scattering
2008
We evaluate the last missing piece of the two-loop QED corrections to the high-energy electron-positron scattering cross section originating from the vacuum polarization by heavy fermions. The calculation is performed within a new approach applicable to a wide class of perturbative problems with mass hierarchy. The result is crucial for the high-precision physics program at existing and future e(+) e(-) colliders.
Deuteron photodisintegration at low energies
1991
All presently available experimental data on deuteron photodisintegration below 40 MeV (i.e., total and differential cross sections, photon asymmetry and neutron polarization) are collected and carefully compared with the present status of the conventional theory (i.e., in the framework of mesontheoretical or semi-phenomenologicalN-N potentials including subnuclear degrees of freedom and relativistic corrections). No significant evidence for a failure of the conventional theory is found within the present experimental accuracy.
Relativistic Effects and the Role of Heavy Meson Exchange in Deuteron Photodisintegration
1997
Relativistic effects and the role of heavy meson exchange in deuteron photodisintegration are studied systematically for photon energies below the pion production threshold. In a (p/M)-expansion, all leading order relativistic one-body and pi-exchange as well as all static heavy meson exchange currents consistent with the Bonn OBEPQ model are included. In addition, one- and two-body boost effects have been investigated. Sizeable effects from the various two-body contributions beyond pi-exchange have been found in almost every observable considered, i.e., differential cross section and single polarization observables.
Astrophysical S-factor for the $^{2}H(ρ,γ)^{3}$ He reaction at big-bang nucleosynthesis energies
2020
10th European Summer School on Experimental Nuclear Astrophysics , Catania, Italy, 16 Jun 2019 - 23 Jun 2019; The European physical journal / Web of Conferences 227, 02015 (2020). doi:10.1051/epjconf/202022702015