DSpace Collection:https://hdl.handle.net/2440/108262024-03-28T08:55:16Z2024-03-28T08:55:16ZCharacterization of SABRE crystal NaI-33 with direct underground countingAntonello, M.Arnquist, I.J.Barberio, E.Baroncelli, T.Benziger, J.Bignell, L.J.Bolognino, I.Calaprice, F.Copello, S.Dafinei, I.D’Angelo, D.D’Imperio, G.D’Incecco, M.Di Carlo, G.Diemoz, M.Di Giacinto, A.Di Ludovico, A.Dix, W.Duffy, A.R.Hoppe, E.et al.https://hdl.handle.net/2440/1303982021-10-10T06:17:17Z2021-01-01T00:00:00ZTitle: Characterization of SABRE crystal NaI-33 with direct underground counting
Author: Antonello, M.; Arnquist, I.J.; Barberio, E.; Baroncelli, T.; Benziger, J.; Bignell, L.J.; Bolognino, I.; Calaprice, F.; Copello, S.; Dafinei, I.; D’Angelo, D.; D’Imperio, G.; D’Incecco, M.; Di Carlo, G.; Diemoz, M.; Di Giacinto, A.; Di Ludovico, A.; Dix, W.; Duffy, A.R.; Hoppe, E.; et al.
Abstract: Ultra-pure NaI(Tl) crystals are the key element for a model-independent verification of the long standing DAMA result and a powerful means to search for the annual modulation signature of dark matter interactions. The SABRE collaboration has been developing cutting-edge techniques for the reduction of intrinsic backgrounds over several years. In this paper we report the first characterization of a 3.4 kg crystal, named NaI-33, performed in an underground passive shielding setup at LNGS. NaI-33 has a record low ³⁹K contamination of 4.3 ± 0.2 ppb as determined by mass spectrometry. We measured a light yield of 11.1 ± 0.2 photoelectrons/keV and an energy resolution of 13.2% (FWHM/E) at 59.5 keV. We evaluated the activities of ²²⁶Ra and ²²⁸Th inside the crystal to be 5.9±0.6 μBq/kg and 1.6±0.3 μBq/kg, respectively, which would indicate a contamination from ²³⁸U and ²³²Th at part-per-trillion level. We measured an activity of 0.51 ± 0.02 mBq/kg due to ²¹⁰Pb out of equilibrium and a α quenching factor of 0.63 ± 0.01 at 5304 keV. We illustrate the analyses techniques developed to reject electronic noise in the lower part of the energy spectrum. A cut-based strategy and a multivariate approach indicated a rate, attributed to the intrinsic radioactivity of the crystal, of ∼1 count/day/kg/keV in the [5–20] keV region.
Description: Published online: 09 April 20212021-01-01T00:00:00ZInstanton contributions to the low-lying hadron mass spectrumThomas, S.Kamleh, W.Leinweber, D.https://hdl.handle.net/2440/1077702023-11-19T13:48:47Z2015-01-01T00:00:00ZTitle: Instanton contributions to the low-lying hadron mass spectrum
Author: Thomas, S.; Kamleh, W.; Leinweber, D.
Abstract: The role of instanton-like objects in the QCD vacuum on the mass spectrum of low-lying light hadrons is explored in lattice QCD. Using overimproved stout-link smearing, tuned to preserve instanton-like objects in the QCD vacuum, the evolution of the mass spectrum under smearing is examined. The calculation is performed using a 20³×40 dynamical fat-link-irrelevant-clover (FLIC) fermion action ensemble with lattice spacing 0.126 fm. Through the consideration of a range of pion masses, the effect of the vacuum instanton content is compared at a common pion mass. While the qualitative features of ground-state hadrons are preserved on instanton-dominated configurations, the excitation spectrum experiences significant changes. The underlying physics revealed shows little similarity to the direct-instanton-interaction predictions of the instanton liquid model.
Description: Published 24 November 20152015-01-01T00:00:00ZMagnetic properties of the nucleon in a uniform background fieldPrimer, T.Kamleh, W.Leinweber, D.Burkardt, M.https://hdl.handle.net/2440/864742023-11-21T14:21:32Z2014-01-01T00:00:00ZTitle: Magnetic properties of the nucleon in a uniform background field
Author: Primer, T.; Kamleh, W.; Leinweber, D.; Burkardt, M.
Abstract: We present results for the magnetic moment and magnetic polarizability of the neutron and the magnetic moment of the proton. These results are calculated using the uniform background field method on 323×64 dynamical QCD lattices provided by the PACS-CS Collaboration as part of the ILDG. We use a uniform background magnetic field quantized by the periodic spatial volume. We investigate ways to improve the effective energy plots used to calculate magnetic polarizabilities, including the use of correlation matrix techniques with various source smearings.2014-01-01T00:00:00ZJ∕Ψ mass shift and J∕Ψ‐nuclear bound stateTsushima, K.Lu, D.Krein, G.Thomas, A.https://hdl.handle.net/2440/801332021-10-10T08:08:48Z2011-01-01T00:00:00ZTitle: J∕Ψ mass shift and J∕Ψ‐nuclear bound state
Author: Tsushima, K.; Lu, D.; Krein, G.; Thomas, A.
Editor: Kizilersu, A.; Thomas, A.W.
Abstract: We calculate mass shift of the J∕Ψ meson in nuclear matter arising from the modification of DD, DD∗ and D∗D∗ meson loop contributions to the J∕Ψ self‐energy. The estimate includes the in‐medium D and D∗ meson masses consistently. The J∕Ψ mass shift (scalar potential) calculated is negative (attractive), and is complementary to the attractive potential obtained from the QCD color van der Waals forces. Some results for the J∕Ψ‐nuclear bound state energies are also presented.
Description: Also published as a book chapter: T(r)opical QCD II Workshop, Sunday 26th September - Friday 1st October 2010, Cairns - Australia / A. Kizilersü and A. W. Thomas (eds.):39-44.2011-01-01T00:00:00Z