Search results for "Lepton"
showing 10 items of 1512 documents
Prototype tests for a highly granular scintillator-based hadronic calorimeter
2017
Within the CALICE collaboration, several concepts for the hadronic calorimeter of a future lepton collider detector are studied. After having demonstrated the capabilities of the measurement methods in "physics prototypes", the focus now lies on improving their implementation in "technological prototypes", that are scalable to the full linear collider detector. The Analogue Hadronic Calorimeter (AHCAL) concept is a sampling calorimeter of tungsten or steel absorber plates and plastic scintillator tiles read out by silicon photomultipliers (SiPMs) as active components. The front-end electronics is fully integrated into the active layers of the calorimeter and is designed for minimal power co…
PINGU: a vision for neutrino and particle physics at the South Pole
2017
The Precision IceCube Next Generation Upgrade (PINGU) is a proposed low-energy in-fill extension to the IceCube Neutrino Observatory. With detection technology modeled closely on the successful IceCube example, PINGU will provide a 6Mton effective mass for neutrino detection with an energy threshold of a few GeV. With an unprecedented sample of over 60,000 atmospheric neutrinos per year in this energy range, PINGU will make highly competitive measurements of neutrino oscillation parameters in an energy range over an order of magnitude higher than long-baseline neutrino beam experiments. PINGU will measure the mixing parameters $\theta_{\rm 23}$ and $\Delta m^2_{\rm 32}$, including the octan…
NEXT, high-pressure xenon gas experiments for ultimate sensitivity to Majorana neutrinos
2012
In this paper we describe an innovative type of Time Projection Chamber (TPC), which uses high-pressure xenon gas (HPXe) and electroluminescence amplification of the ionization charge as the basis of an apparatus capable of fully reconstructing the energy and topological signature of rare events. We will discuss a specific design of such HPXe TPC, the NEXT-100 detector, that will search for neutrinoless double beta decay events using 100-150 kg of xenon enriched in the isotope Xe-136. NEXT-100 is currently under construction, after completion of an accelerated and very successful R&D period. It will be installed at the Laboratorio Subterr��neo de Canfranc (LSC), in Spain. The commission…
The MORA project
2018
The MORA (Matter's Origin from the RadioActivity of trapped and oriented ions) project aims at measuring with unprecedented precision the D correlation in the nuclear beta decay of trapped and oriented ions. The D correlation offers the possibility to search for new CP-violating interactions, complementary to searches done at the LHC and with Electric Dipole Moments. Technically, MORA uses an innovative in-trap orientation method which combines the high trapping efficiency of a transparent Paul trap with laser orientation techniques. The trapping, detection, and laser setups are under development, for first tests at the Accelerator laboratory, JYFL, in the coming years.
Design of the Magnet System of the Neutron Decay Facility PERC
2018
The PERC (Proton and Electron Radiation Channel) facility is currently under construction at the research reactor FRM II, Garching. It will serve as an intense and clean source of electrons and protons from neutron beta decay for precision studies. It aims to contribute to the determination of the Cabibbo-Kobayashi-Maskawa quark-mixing element $V_{ud}$ from neutron decay data and to search for new physics via new effective couplings. PERC's central component is a 12m long superconducting magnet system. It hosts an 8m long decay region in a uniform field. An additional high-field region selects the phase space of electrons and protons which can reach the detectors and largely improves system…
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at √s = 7 TeV with the ATLAS detector
2011
The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton–proton collisions at a centre-of-mass energy of √s =7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb[superscript −1]. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the ra…
Search for supersymmetric particles in events with lepton pairs and large missing transverse momentum in sqrt{s} = 7 TeV proton-proton collisions wit…
2011
Results are presented of searches for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons in √ s = 7 TeV proton–proton collisions at the Large Hadron Collider. Search strategies requiring lepton pairs with identical-sign or opposite-sign electric charges are described. In a data sample corresponding to an integrated luminosity of 35 pb−1 collected with the ATLAS detector, no significant excesses are observed. Based on specific benchmark models, limits are placed on the squark mass between 450 and 690 GeV for squarks approximately degenerate in mass with gluinos, depending on the supersymmetric mass hierarchy…
Search for heavy neutrinos and right-handed W bosons in events with two leptons and jets in pp collisions at √s=7 TeV with the ATLAS detector
2012
This letter reports on a search for hypothetical heavy neutrinos, N, and right-handed gauge bosons, WR, in events with high transverse momentum objects which include two reconstructed leptons and at least one hadronic jet. The results were obtained from data corresponding to an integrated luminosity of 2.1 fb−1 collected in proton–proton collisions at √s=7 TeV with the ATLAS detector at the CERN Large Hadron Collider. No excess above the Standard Model background expectation is observed. Excluded mass regions for Majorana and Dirac neutrinos are presented using two approaches for interactions that violate lepton and lepton-flavor numbers. One approach uses an effective operator framework, t…
Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
2017
This article reports world averages of measurements of $b$-hadron, $c$-hadron, and $\tau$-lepton properties obtained by the Heavy Flavor Averaging Group using results available through summer 2016. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, \CP~violation parameters, parameters of semileptonic decays and CKM matrix elements.
Dispersion relation formalism for the two-photon exchange correction to elastic muon-proton scattering: elastic intermediate state
2018
We evaluate the two-photon exchange correction to the unpolarized cross section in the elastic muon-proton scattering within dispersion relations. One of the six independent invariant amplitudes requires a subtraction. We fix the subtraction function to the model estimate of the full two-photon exchange at one of three MUSE beam energies and make a prediction for the two other energies. Additionally, we present single and double polarization observables accounting for the lepton mass.