Search results for "Collider"
showing 10 items of 1690 documents
Search for the decay Bs0→μ+μ− with the ATLAS detector
2012
A blind analysis searching for the decay B-s(0) -> mu(+)mu(-) has been performed using proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. W ...
Search for the standard model Higgs boson inℓν+jetsfinal states in9.7 fb−1ofpp¯collisions with the D0 detector
2013
Searches for the Higgs boson have started as soon as the underlying model for particle mass generation has been proposed, and the search went on for several decades at LEP, Tevatron and LHC. Last year the ATLAS and CMS Collaborations at the Large Hadron Collider (LHC) have reported the observation of a new boson [1, 2]. At the same time the CDF and D0 Collaborations reported combined evidence for a particle, with a mass consistent with that of the new boson observed at LHC [3]. This thesis presents the search by the D0 collaboration for the SM Higgs boson using events containing one isolated charged lepton (l = e or μ), a significant imbalance in transverse energy (6ET ), and two or more je…
Combining LSND and Atmospheric Anomalies in a Three-Neutrino Picture
2001
We investigate the three-neutrino mixing scheme for solving the atmospheric and LSND anomalies. We find the region in the parameter space that provides a good fit to the LSND and the SK atmospheric data, taking into account the CHOOZ constraint. We demonstrate that the goodness of this fit is comparable to that of the conventional fit to the solar and atmospheric data. Large values of the LSND angle are favoured and $\sin^2(2\theta_{\rm LSND})$ can be as high as 0.1. This can have important effects on the atmospheric electron neutrino ratios as well as on down-going multi-GeV muon neutrino ratios. We examine the possibility of distinguishing this scheme from the conventional one at the long…
Neutrino mass hierarchy and Majorana CP phases within the Higgs triplet model at the LHC
2007
Neutrino masses may be generated by the VEV of an $SU(2)_L$ Higgs triplet. We assume that the doubly charged component of such a triplet has a mass in the range of several 100 GeV, such that it is accessible at LHC. Its decay into like-sign leptons provides a clean experimental signature, which allows for a direct test of the neutrino mass matrix. By exploring the branching ratios of this decay into leptons of various flavours, we show that within this model the type of the neutrino mass spectrum (normal, inverted or quasi-degenerate) might actually be resolved at the LHC. Furthermore, we show that within the Higgs triplet model for neutrino mass the decays of the doubly charged scalar into…
Measurement of the mass and lifetime of the charmed strange baryon $\Xi_{c}^{+}$
1989
Abstract We have observed six unambiguous decays of the charmed strange baryon Ξc+ (or charge conjugate Ξc−) in the 230 GeV/c negative pions or kaons on a copper target at the CERN SPS using silicon microstrip detectors and charge-coupled devices for vertex reconstruction. Three of them have been reconstructed through the decay chain Ξc+ →Ξ−π+π+, Ξ− →Λ0π−, Λ0 →pπ− and the other three through the decay chain Ξc+ →Σ+K−π+ →pπ0. We present our measurements of the mass, lifetime and production cross-section of the Ξc+, as well as of the branching ration for the two decay modes.
Production of the charmed baryon $\Lambda_{c}^{+}$ in $\pi^{-}$Cu and K$^{-}$Cu interactions at 230 GeV
1990
Abstract We present results from the NA32 experiment at CERN on the production characteristics of the charmed baryon Λ+c in 230 GeV π−Cu and K−Cu interactions. A high resolution vertex detector consisting of change-coupled devices and silicon microstrip detectors allowed the selection of a very clean sample of 154 Λ+c → pK−π+ (and charge conjugate) decays. Results on differential and integrated cross sections are given.
Long-range angular correlations of π, K and p in p–Pb collisions at sNN=5.02 TeV
2013
Angular correlations between unidentified charged trigger particles and various species of charged associated particles (unidentified particles, pions, kaons, protons and antiprotons) are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV in the transverse-momentum range 0.3 < p(T) < 4 GeV/c. The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range vertical bar n(lab)vertical bar < 0.8. Fourier coefficients are extracted from the long-range correlations projected onto the azimuthal angle difference and studied as a function of p(T) and in intervals of event multiplicity. In high-multipl…
Measurement of underlying event characteristics using charged particles inppcollisions ats=900 GeVand 7 TeV with the ATLAS detector
2011
Measurements of charged particle distributions, sensitive to the underlying event, have been performed with the ATLAS detector at the LHC. The measurements are based on data collected using a minimum-bias trigger to select proton-proton collisions at center-of-mass energies of 900 GeV and 7 TeV. The "underlying event" is defined as those aspects of a hadronic interaction attributed not to the hard scattering process, but rather to the accompanying interactions of the rest of the proton. Three regions are defined in azimuthal angle with respect to the highest transverse momentum charged particle in the event, such that the region transverse to the dominant momentum-flow is most sensitive to …
D meson enhancement in pp collisions at the LHC due to nonlinear gluon evolution
2004
When nonlinear effects on the gluon evolution are included with constraints from HERA, the gluon distribution in the free proton is enhanced at low momentum fractions, x < 0.01, and low scales, Q^2 < 10 GeV^2, relative to standard, DGLAP-evolved, gluon distributions. Consequently, such gluon distributions can enhance charm production in pp collisions at center of mass energy 14 TeV by up to a factor of five at midrapidity, y \sim 0, and transverse momentum p_T -> 0 in the most optimistic case. We show that most of this enhancement survives hadronization into D mesons. Assuming the same enhancement at leading and next-to-leading order, we show that the D enhancement may be measured …
Prospects for probing the gluon density in protons using heavy quarkonium hadroproduction
2001
We examine carefully bottomonia hadroproduction in proton colliders, especially focusing on the LHC, as a way of probing the gluon density in protons. To this end we develop some previous work, getting quantitative predictions and concluding that our proposal can be useful to perform consistency checks of the parameterization sets of different parton distribution functions.