Search results for "experimental physics"
showing 6 items of 26 documents
Measurement of t ¯ t production with a veto on additional central jet activity in pp collisions at √ s = 7 TeV using the ATLAS detector
2012
A measurement of the jet activity in t[bar over t] events produced in proton–proton collisions at a centre-of-mass energy of 7 TeV is presented, using 2.05 fb[superscript −1] of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. The t[bar over t] events are selected in the dilepton decay channel with two identified b-jets from the top quark decays. Events are vetoed if they contain an additional jet with transverse momentum above a threshold in a central rapidity interval. The fraction of events surviving the jet veto is presented as a function of this threshold for four different central rapidity interval definitions. An alternate measurement is also perfor…
Experimental measurements for studying angular and spectral variation of thermal infrared emissivity
2004
One condition for precise multiangle algorithms for estimating sea and land surface temperature with the data from the Advanced Along Track Scanning Radiometer is accurate knowledge of the angular variation of surface emissivity in the thermal IR spectrum region. Today there are very few measurements of this variation. The present study is conducted to provide angular emissivity measurements for five representative samples (water, clay, sand, loam, gravel). The measurements are made in one thermal IR broadband (8-13 microm) and three narrower bands (8.2-9.2, 10.3-11.3, and 11.5-12.5 microm) at angles of 0 degrees-60 degrees (at 5 degrees increments) to the surface normal. The results show a…
Multiplicity dependence of π, K, and p production in pp collisions at √s = 13 TeV
2020
This paper presents the measurements of π±, K±, p and p¯¯¯ transverse momentum (pT) spectra as a function of charged-particle multiplicity density in proton–proton (pp) collisions at s√ = 13 TeV with the ALICE detector at the LHC. Such study allows us to isolate the center-of-mass energy dependence of light-flavour particle production. The measurements reported here cover a pT range from 0.1 to 20 GeV/c and are done in the rapidity interval |y|<0.5. The pT-differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at s√ = 7 TeV, which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper.…
Detailed studies of 100 Mo two-neutrino double beta decay in NEMO-3
2019
Final results on 82Se double beta decay to the ground state of 82Kr from the NEMO-3 experiment
2018
Using data from the NEMO-3 experiment, we have measured the two-neutrino double beta decay (2νββ) half-life of 82Se as T2ν1/2=[9.39±0.17( stat )±0.58( syst )]×1019 y under the single-state dominance hypothesis for this nuclear transition. The corresponding nuclear matrix element is ∣∣M2ν∣∣=0.0498±0.0016. In addition, a search for neutrinoless double beta decay (0νββ) using 0.93 kg of 82Se observed for a total of 5.25 y has been conducted and no evidence for a signal has been found. The resulting half-life limit of T0ν1/2>2.5×1023 y (90% C.L. ) for the light neutrino exchange mechanism leads to a constraint on the effective Majorana neutrino mass of ⟨mν⟩<(1.2−3.0) eV , where the range reflec…
Charged-particle production as a function of multiplicity and transverse spherocity in pp collisions at √s = 5.02 and 13 TeV
2019
We present a study of the inclusive chargedparticle transverse momentum (pT) spectra as a function of charged-particle multiplicity density at mid-pseudorapidity, dNch/dη, in pp collisions at √s = 5.02 and 13 TeV covering the kinematic range |η| 0). The pT spectra are reported for two multiplicity estimators covering different pseudorapidity regions. The pT spectra normalized to that for INEL > 0 show little energy dependence. Moreover, the high-pT yields of charged particles increase faster than the charged-particle multiplicity density. The average pT as a function of multiplicity and transverse spherocity is reported for pp collisions at √s = 13 TeV. For low- (high-) spherocity events, c…