Track Segments within Hadronic Showers using the CALICE AHCal

Using the high granular CALICE analog hadron calorimeter (AHCal) a tracking algorithm capable of identifying MIP-like tracks within hadronic showers is presented. Such an algorithm provides excellent tools for detector calibration and for studies of the substructure of hadronic showers. The properties of the identified tracks are used as observables for a Monte-Carlo to data comparison.Comment: 6 pages, 9 figures, LCWS2010 Proceedin

Recent results of the CMS experiment

The CMS experiment is a multi-purpose detector successfully operated at the LHC where predominantly pp collisions take place at various centre-of-mass energies up to sqrt(s)=8 TeV so far. Several weeks per year also heavy-ion collisions take place leading to interesting studies in Pb-Pb and p-Pb collisions at sqrt(s_(NN))=2.76 TeV and sqrt(s_(NN))=5.02 TeV centre-of-mass energies per nucleon, respectively. The excellent performance of the accelerator and the experiment allows for dedicated physics measurements over a wide range of subjects, starting from particle identification, encompassing forward physics, Standard Model measurements in multijet, boson, heavy flavour and top quark physics, building the basis for new physics searches interpreted within the framework of various models and theories. These pursued pp physics subjects are complemented by a rich heavy ion physics programme.Comment: 20 pages, 10 figures, 1 table, proceedings of 52. International Winter Meeting on Nuclear Physics, Bormio 201

CP-conserving and CP-violating properties in semileptonic Bs decays with the D0 experiment

A search for CP violation has been performed in a sample of semileptonic Bs decays corresponding to approximately 5fb^-1 of data collected by the D0 detector in Run II at the Fermilab Tevatron collider. A time-dependent fit to the distributions of Bs candidates yields the flavour-specific asymmetry a^s_fs = [-1.7 +/- 9.1 (stat) +1.2 -2.3 (syst)] x 10^-3, corresponding to the most precise measurement to date for this CP violation parameter. Furthermore a search for the semi-inclusive process Bs to Ds^(*)Ds^(*) has been performed on a data sample of 2.8fb^-1. 26.6 +/- 8.4 signal events are observed with a significance of 3.2 standard deviations above background, leading to a branching ratio of 0.035 +/- 0.010 (stat) +/- 0.011 (syst). Under certain theoretical assumptions, these double-charm final states saturate CP-even eigenstates in the $B_s$ decays, resulting in a width difference of Delta Gamma_s^CP / Gamma_s = 0.072 +/- 0.021 (stat) +/- 0.022 (syst).Comment: 3 pages, 1 figur

Determination of the strong coupling constant from inclusive jet cross section in ppbar collisions at sqrt(s)=1.96 TeV with the D0 experiment

The strong coupling constant alpha_s and its dependence on the momentum scale is determined from the p_T dependence of the inclusive jet cross section in ppbar collisions at sqrt(s)=1.96 TeV measured with the D0 experiment. The jet transverse momentum range of 50 < p_T < 145 GeV contributes to the determination. Using perturbative QCD caclulations to order O(alpha_s^3) combined with resummed threshold corrections to order O(alpha_s^4) an alpha_s(M_Z)=0.1161^{+0.0041}_{-0.0048} is obtained. This is the most precise result from a hadron-hadron collider.Comment: 5 pages, 2 figure