Search results for "Nuclear physic"
showing 10 items of 5307 documents
Search for a Charged Higgs Boson Produced in the Vector-Boson Fusion Mode with DecayH±→W±ZusingppCollisions ats=8 TeVwith the ATLAS Experiment
2015
A search for a charged Higgs boson, H-+/-, decaying to a W-+/- boson and a Z boson is presented. The search is based on 20.3 fb(-1) of proton-proton collision data at a center-of-mass energy of 8 TeV recorded with the ATLAS detector at the LHC. The H-+/- boson is assumed to be produced via vector-boson fusion and the decays W-+/- -> q (q') over bar and Z -> e(+)e(-)/mu(+)mu(-) are considered. The search is performed in a range of charged Higgs boson masses from 200 to 1000 GeV. No evidence for the production of an H+ boson is observed. Upper limits of 31-1020 fb at 95% C.L. are placed on the cross section for vector-boson fusion production of an H-+/- boson times its branching fraction to W…
Electron-cooled accumulation of 4 × 109positrons for production and storage of antihydrogen atoms
2016
Four billion positrons (e+) are accumulated in a Penning–Ioffe trap apparatus at 1.2 K and <6 × 10−17 Torr. This is the largest number of positrons ever held in a Penning trap. The e+ are cooled by collisions with trapped electrons (e−) in this first demonstration of using e− for efficient loading of e+ into a Penning trap. The combined low temperature and vacuum pressure provide an environment suitable for antihydrogen () production, and long antimatter storage times, sufficient for high-precision tests of antimatter gravity and of CPT.
Search for a multi-Higgs-boson cascade inW+W−bb¯events with the ATLAS detector inppcollisions ats=8 TeV
2014
A search is presented for new particles in an extension to the Standard Model that includes a heavy Higgs boson (H-0), an intermediate charged Higgs-boson pair (H-+/-), and a light Higgs boson (h(0)). The analysis searches for events involving the production of a single heavy neutral Higgs boson which decays to the charged Higgs boson and a W boson, where the charged Higgs boson subsequently decays into a W boson and the lightest neutral Higgs boson decaying to a bottom-antibottom-quark pair. Such a cascade results in a W-boson pair and a bottom-antibottom-quark pair in the final state. Events with exactly one lepton, missing transverse momentum, and at least four jets are selected from a d…
Mass Measurements of Proton-rich Nuclei with JYFLTRAP
2011
The Penning trap setup JYFLTRAP, connected to the IGISOL facility, has been extensively used for atomic mass measurements of exotic nuclei. On the proton rich side of the chart of nuclei mass measurements have mostly contributed to fundamental physics and nuclear astrophysics studies with about 100 atomic masses measured. peerReviewed
Chiral approach to antikaon s- and p-wave interactions in dense nuclear matter
2006
The properties of the antikaons in nuclear matter are investigated from a chiral unitary approach which incorporates the s- and p-waves of the ${\bar K}N$ interaction. To obtain the in-medium meson-baryon amplitudes we include, in a self-consistent way, Pauli blocking effects, meson self-energies corrected by nuclear short-range correlations and baryon binding potentials. We pay special attention to investigating the validity of the on-shell factorization, showing that it cannot be applied in the evaluation of the in-medium corrections to the p-wave amplitudes. In nuclear matter at saturation energy, the $\Lambda$ and $\Sigma$ develop an attractive potential of about -30 MeV, while the $\Si…
Unitarity constraint for threshold coherent pion photoproduction on the deuteron
1997
The contribution of the two-step process {gamma}d{r_arrow}pn{r_arrow}{pi}{sup 0}d to the imaginary part of the amplitude for coherent pion production on the deuteron is calculated at threshold exploiting unitarity constraints. The result shows that this absorptive process is not negligible and has to be considered in an extraction of the elementary neutron production amplitude from the {gamma}d{r_arrow}{pi}{sup 0}d cross section at threshold. {copyright} {ital 1997} {ital The American Physical Society}
Mixed MHD convection and Tritium transport in fusion-relevant configurations
2005
Mixed MHD flow and Tritium transport were computed for a slender poloidal duct, representative of a DEMO HCLL blanket element. 2-D flow and temperature fields were computed in the duct's cross section under the assumption of parallel, fully developed flow, while Tritium concentration C was found by solving a fully 3-D problem with simplifying assumptions at the duct's ends. The spatial distribution of C depended on the intensity and direction of the forced flow. Significant peak factors were obtained if the net flow rate was so low that re-circulation occurred; C maxima were attained near the walls for upward flow, in the core region for downward flow.
Characteristics of the diffuse astrophysical electron and Tau neutrino flux with six years of IceCube high energy cascade data
2020
We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of φastro=1.66-0.27+0.25 at E0=100 TeV, in agreement with IceCube's complementary muon neutrino results and wit…
A search for light dark matter in XENON10 data
2011
We report results of a search for light (3.5x10^{-42} cm^2, for a dark matter particle mass m_{\chi}=8 GeV. We find that our data strongly constrain recent elastic dark matter interpretations of excess low-energy events observed by CoGeNT and CRESST-II, as well as the DAMA annual modulation signal.
Dark matter results from 225 live days of XENON100 data
2012
We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso (LNGS) for 13 months during 2011 and 2012. XENON100 features an ultra-low electromagnetic background of (5.3 \pm 0.6) \times 10^-3 events (kg day keVee)^-1 in the energy region of interest. A blind analysis of 224.6 live days \times 34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the pre-defined nuclear recoil energy range of 6.6-30.5 keVnr are consistent with the background expectation of (1.0 \pm 0.2) events. A Profile Likelihood analysis using a 6.6-43.3 keVnr energy range sets the most stringent limit o…