Search for a Low Mass Standard Model Higgs Boson at D0 in ppbar Collisions at s=1.96TeV\sqrt{s}=1.96 TeV

We present combined searches for the Low Mass Standard Model Higgs boson at a center-of-mass energy of $\sqrt{s}=$1.96 TeV, using up to 5 fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron collider. The major contributing processes are associated production ($WH\to l\nu bb$, $ZH\to\nu\nu bb$, $ZH\to ll bb$). The significant improvements across the full mass range resulting from the larger data sets and improved analyses as well as future prospects are discussed

Soft QCD at Tevatron

Experimental studies of soft Quantum Chromodynamics (QCD) at Tevatron are reported in this note. Results on inclusive inelastic interactions, underlying events, double parton interaction and exclusive diffractive production and their implications to the Large Hadron Collider (LHC) physics are discussed

Measurement of Z/γ\gamma+jet+X and γ\gamma+b/c+X Cross Sections with the D0 Detector

We present measurements of differential cross sections for the inclusive $Z/\gamma^*$ + jet production and the inclusive photon plus heavy flavor production in a data sample of 1fb$^{-1}$ collected with the D{\O}detector in proton-antiproton collisions at $\sqrt{s}$=1.96 TeV. In the first measurement, we compare kinematic distributions of the $Z/\gamma^*$ and the jets as well as various angles of the $Z$+jet system with different Monte Carlo event generators and next-to-leading order perturbative QCD (NLO pQCD) predictions with non-perturbative corrections applied. In the second measurement, we compare the results with NLO pQCD predictions, covering photon transverse momenta 30-150 GeV, photon rapidities $|y^{\gamma}| < 1.0$, jet rapidities $|y^{jet}| 15$ GeV

Experimental aspects of jet physics at LHC

Jet physics provides a powerful tool to investigate interaction properties of quarks and gluons. These studies have been possible at an energy never investigated before at LHC. In this proceedings we review the main characteristics of experimental methods to measure jets in proton-proton collisions at center-of-mass energies of 7 and 8 TeV. Novel methods are expected to play an important role for searching new physics at center-of-mass energy of 13 TeV.Comment: Proceedings of the Summer School and Workshop New Trends in High-Energy Physics and QC

Search for CP violation in B^0 -> J/psi K^0_S decays with first LHCb data

We report a measurement of the CP violation in B^0 -> J/\psi K^0_S decays. We perform a time-dependent analysis of the decays reconstructed in 35/pb of LHCb data that was taken in 2010. We measure the CP asymmetry parameterComment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 3 pages, 3 figure

Exclusive dilepton production at forward rapidities in PbPbPbPb collisions

The dilepton production in diffractive and exclusive processes at forward rapidities considering ultraperipheral $PbPb$ collisions at the LHC is investigated. Predictions for the $e^+ e^-$, $\mu^+ \mu^-$ and $\tau^+ \tau^-$ cross sections are presented taking into account of realistic cuts that can be implemented by the LHCb Collaboration in a future experimental analysis. Our results indicate that the background associated with the diffractive production can be strongly suppressed and the exclusive processes can be cleanly separated. For the $\tau^+ \tau^-$ production, the semi and purely leptonic decay channels are considered. Our results indicate that a future experimental analysis of the dilepton production at the LHCb is feasible and can be useful to search for BSM physics.Comment: 7 pages, 3 figures, 3 table

Top quark pair production in the exclusive processes at LHC

We analyze the LHC prospects for measurements of the $t\bar{t}$ pair produced exclusively in photon-photon or semi-exclusively in photon-Pomeron and Pomeron-Pomeron processes using protons tagged in forward proton detectors on both sides of the interaction point. These processes are interesting from the point of view of a possible measurement of the top quark mass and constraining models used in Beyond Standard Model physics. Focusing on the semi-leptonic channel, $t\bar{t}\rightarrow jjbl\nu_l\bar{b}$, making use of the exclusive nature of the final state, together with the use of timing information provided by forward proton detectors, relevant exclusive and inclusive backgrounds are studied in detail for different luminosity (or pile-up) scenarios and found to be important for further considerations. For each of these scenarios, we try to estimate the precision of the top quark mass determination and conclude that statistical significances need to be significantly enlarged for these processes to become competitive with measurements of inclusive $t\bar{t}$ production.Comment: 17 pages, 5 figure

Diffractive di-jet production at the LHC with a Reggeon contribution

We study hard diffractive scattering in hadron–hadron collisions including, on top of the standard Pomeron-initiated processes, contributions due to the exchange of Reggeons. Using a simple model to describe the parton content of the Reggeon, we compute di-jet production in single diffractive and central diffractive events. We show that Reggeon contributions can be sizable at the LHC, and even sometimes dominant, and we identify kinematic windows in which they could be experimentally studied. We argue that suitable measurements must be performed in order to properly constrain the model, and be able to correctly account for Reggeon exchanges in the analysis of the many hard diffractive observables to be measured at the LHC.SCOAP

Producao d Dijatos por Dupla Troca de Pomeron Exclusiva no Experimento D0

The first search for exclusive diffractive dijet production with invariant mass {approx}&gt; 100 GeV in Run II of the Fermilab Tevatron Collider is performed. The set of data used is the Run IIa, corresponding to an integrated luminosity of 30 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV taken with the D0 detector. At 95% CL, an upper limit for the ratio between the number of diffractive exclusive events and the number of non diffractive events is set to be 7.5 x 10{sup -6}, excluding two of the three models proposed to explain this production