Determining R-parity violating parameters from neutrino and LHC data

In supersymmetric models neutrino data can be explained by R-parity violating operators which violate lepton number by one unit. The so called bilinear model can account for the observed neutrino data and predicts at the same time several decay properties of the lightest supersymmetric particle. In this paper we discuss the expected precision to determine these parameters by combining neutrino and LHC data and discuss the most important observables. We show that one can expect a rather accurate determination of the underlying R-parity parameters assuming mSUGRA relations between the R-parity conserving ones and discuss briefly also the general MSSM as well as the expected accuracies in case of a prospective e+ e- linear collider. An important observation is that several parameters can only be determined up to relative signs or more generally relative phases.Comment: 13 pages, 13 figure

Measuring the Higgs Sector

If we find a light Higgs boson at the LHC, there should be many observable channels which we can exploit to measure the relevant parameters in the Higgs sector. We use the SFitter framework to map these measurements on the parameter space of a general weak-scale effective theory with a light Higgs state of mass 120 GeV. Our analysis benefits from the parameter determination tools and the error treatment used in new--physics searches, to study individual parameters and their error bars as well as parameter correlations.Comment: 45 pages, Journal version with comments from refere

Determining Supersymmetric Parameters With Dark Matter Experiments

In this article, we explore the ability of direct and indirect dark matter experiments to not only detect neutralino dark matter, but to constrain and measure the parameters of supersymmetry. In particular, we explore the relationship between the phenomenological quantities relevant to dark matter experiments, such as the neutralino annihilation and elastic scattering cross sections, and the underlying characteristics of the supersymmetric model, such as the values of mu (and the composition of the lightest neutralino), m_A and tan beta. We explore a broad range of supersymmetric models and then focus on a smaller set of benchmark models. We find that by combining astrophysical observations with collider measurements, mu can often be constrained far more tightly than it can be from LHC data alone. In models in the A-funnel region of parameter space, we find that dark matter experiments can potentially determine m_A to roughly +/-100 GeV, even when heavy neutral MSSM Higgs bosons (A, H_1) cannot be observed at the LHC. The information provided by astrophysical experiments is often highly complementary to the information most easily ascertained at colliders.Comment: 46 pages, 76 figure

The Higgs Working Group: Summary Report (2001)

Report of the Higgs working group for the Workshop `Physics at TeV Colliders', Les Houches, France, 21 May - 1 June 2001. It contains 7 separate sections: A. Theoretical Developments B. Higgs Searches at the Tevatron C. Experimental Observation of an invisible Higgs Boson at LHC D. Search for the Standard Model Higgs Boson using Vector Boson Fusion at the LHC E. Study of the MSSM channel $A/H \to \tau \tau$ at the LHC F. Searching for Higgs Bosons in $t\bar t H$ Production G. Studies of Charged Higgs Boson Signals for the Tevatron and the LHCComment: 120 pages, latex, many figures, proceedings of the Workshop `Physics at TeV Colliders', Les Houches, France, 21 May - 1 June 2001, full Author list included in paper. Typos corrected, author list and acknowledgements completed. Convernors: D. Cavalli, A. Djouadi, K. Jakobs, A. Nikitenko, M. Spira, C.E.M. Wagner, W.-M. Ya

In situ commissioning of the ATLAS electromagnetic calorimeter with cosmic muons

In 2006, ATLAS entered the {\it in situ} commissioning phase. The primary goal of this phase is to verify the detector operation and performance with cosmic muons. Using a dedicated cosmic muon trigger from the hadronic Tile calorimeter, a sample of approximately $120\,000$ events was collected in several modules of the barrel electromagnetic (EM) calorimeter between August 2006 and March 2007. As cosmic events are generally non-projective and arrive asynchronously with respect to the trigger clock, methods to improve the standard signal reconstruction for this situation are presented. Various selection criteria for projective muons and clustering algorithms have been tested, leading to preliminary results on calorimeter uniformity in $\eta$ and timing performance

Position resolution and particle identification with the ATLAS EM calorimeter

In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

Global Analysis of the Higgs Candidate with Mass ~ 125 GeV

We analyze the properties of the Higgs candidate with mass ~ 125 GeV discovered by the CMS and ATLAS Collaborations, constraining the possible deviations of its couplings from those of a Standard Model Higgs boson. The CMS, ATLAS and Tevatron data are compatible with Standard Model couplings to massive gauge bosons and fermions, and disfavour several types of composite Higgs models unless their couplings resemble those in the Standard Model. We show that the couplings of the Higgs candidate are consistent with a linear dependence on particle masses, scaled by the electroweak scale ~ 246 GeV, the power law and the mass scale both having uncertainties ~ 20%.Comment: 22 pages, 9 figures, v2 incorporates experimental data released during July 2012 and corrected (and improved) treatment of mass dependence of coupling

Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam

A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245 GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of phi=0.28 in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on Geant which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 GeV and 180 GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10% sqrt(E) for the sampling term and about 0.2% for the local constant term

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured