0000000001302607

AUTHOR

E. Perez

Measurement of the top quark mass in the dilepton channel

We present a measurement of the top quark mass in the dilepton channel based on approximately 370/pb of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We employ two different methods to extract the top quark mass. We show that both methods yield consistent results using ensemble tests of events generated with the D0 Monte Carlo simulation. We combine the results from the two methods to obtain a top quark mass m_t = 178.1 +/- 8.2 GeV. The statistical uncertainty is 6.7 GeV and the systematic uncertainty is 4.8 GeV.

research product

Search for scalar leptoquarks in the acoplanar jet topology in pp¯ collisions at s=1.96 TeV

A search for leptoquarks has been performed in 310 pb{sup -1} of data from p{bar p} collisions at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider. The topology analyzed consists of acoplanar jets with missing transverse energy. The data show good agreement with standard model expectations, and a lower mass limit of 136 GeV has been set at the 95% C.L. for a scalar leptoquark decaying exclusively into a quark and a neutrino.

research product

Calorimetry triggering in ATLAS

The ATLAS experiment is preparing for data taking at 14 TeV collision energy. A rich discovery physics program is being prepared in addition to the detailed study of Standard Model processes which will be produced in abundance. The ATLAS multi-level trigger system is designed to accept one event in 2 105 to enable the selection of rare and unusual physics events. The ATLAS calorimeter system is a precise instrument, which includes liquid Argon electro-magnetic and hadronic components as well as a scintillator-tile hadronic calorimeter. All these components are used in the various levels of the trigger system. A wide physics coverage is ensured by inclusively selecting events with candidate …

research product

Measurement of the ratios of the Z/γ∗+⩾n jet production cross sections to the total inclusive Z/γ∗ cross section in pp¯ collisions at s=1.96 TeV

We present a study of events with Z bosons and jets produced at the Fermilab Tevatron Collider in ppbar collisions at a center of mass energy of 1.96 TeV. The data sample consists of nearly 14,000 Z/G* -> e+e- candidates corresponding to the integrated luminosity of 340 pb-1 collected using the D0 detector. Ratios of the Z/G* + >= n jet cross sections to the total inclusive Z/G* cross section have been measured for n = 1 to 4 jet events. Our measurements are found to be in good agreement with a next-to-leading order QCD calculation and with a tree-level QCD prediction with parton shower simulation and hadronization.

research product

Erratum to: “Search for particles decaying into a Z boson and a photon in pp¯ collisions at s=1.96 TeV” [Phys. Lett. B 641 (2006) 415]

Search for particles decaying into a Z boson and a photon in collisions p (p)over-bar at root s = 1.96 TeV (vol 641, pg 415, 2006)

research product

Measurement of the isolated photon cross section in pp¯ collisions at s=1.96 TeV

The cross section for the inclusive production of isolated photons has been measured in p anti-p collisions at sqrt{s}=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider. The photons span transverse momenta 23 to 300 GeV and have pseudorapidity |eta|<0.9. The cross section is compared with the results from two next-to-leading order perturbative QCD calculations. The theoretical predictions agree with the measurement within uncertainties.

research product

Search for R-parity violating supersymmetry via the LLE¯ couplings λ121, λ122 or λ133 in pp¯ collisions at s=1.96 TeV

A search for gaugino pair production with a trilepton signature in the framework of R-parity violating supersymmetry via the couplings lambda_121, lambda_122, or lambda_133 is presented. The data, corresponding to an integrated luminosity of L~360/pb, were collected from April 2002 to August 2004 with the D0 detector at the Fermilab Tevatron Collider, at a center-of-mass energy of sqrt(s)=1.96 TeV. This analysis considers final states with three charged leptons with the flavor combinations eel, mumul, and eetau (l=e or mu). No evidence for supersymmetry is found and limits at the 95% confidence level are set on the gaugino pair production cross section and lower bounds on the masses of the …

research product

Event reconstruction algorithms for the ATLAS trigger

The ATLAS experiment under construction at CERN is due to begin operation at the end of 2007. The detector will record the results of proton-proton collisions at a centerof- mass energy of 14 TeV. The trigger is a three-tier system designed to identify in real-time potentially interesting events that are then saved for detailed offline analysis. The trigger system will select approximately 200 Hz of potentially interesting events out of the 40 MHz bunch-crossing rate (with 109 interactions per second at the nominal luminosity). Algorithms used in the trigger system to identify different event features of interest will be described, as well as their expected performance in terms of selection…

research product

Search for particles decaying into a Z boson and a photon in pp¯ collisions at s=1.96 TeV

Abstract We present the results of a search for a new particle X produced in p p ¯ collisions at s = 1.96 TeV and subsequently decaying to Zγ. The search uses 0.3 fb−1 of data collected with the DO detector at the Fermilab Tevatron Collider. We set limits on the production cross section times the branching fraction σ ( p p ¯ → X ) × B ( X → Z γ ) that range from 0.4 to 3.5 pb at the 95% C.L. for X with invariant masses between 100 and 1000 GeV / c 2 , over a wide range of X decay widths.

research product

Experimental Discrimination between Charge2e/3Top Quark and Charge4e/3Exotic Quark Production Scenarios

We present the first experimental discrimination between the 2e/3 and 4e/3 top quark electric charge scenarios, using top quark pairs (ttbar) produced in ppbar collisions at sqrt{s}=1.96 TeV by the Fermilab Tevatron collider. We use 370 pb-1 of data collected by the D0 experiment and select events with at least one high transverse momentum electron or muon, high transverse energy imbalance, and four or more jets. We discriminate between b- and bbar-quark jets by using the charge and momenta of tracks within the jet cones. The data is consistent with the expected electric charge, |q|=2e/3. We exclude, at the 92% C.L., that the sample is solely due to the production of exotic quark pairs QQba…

research product

Search for W′ boson production in the W′→tb¯ decay channel

We present a search for the production of a new heavy gauge boson W' that decays to a top quark and a bottom quark. We have analyzed 230 pb(-1) of data collected with the DO detector at the Fermilab Tevatron collider at a center-of-mass energy of 1.96 TeV. No significant excess of events above the standard model expectation is found in any region of the final state invariant mass distribution. We set upper limits on the production cross section of W' bosons times branching ratio to top quarks at the 95% confidence level for several different W, boson masses. We exclude masses between 200 and 610 GeV for a W' boson with standard-model-like couplings, between 200 and 630 GeV for a W, boson wi…

research product

CCDC 210648: Experimental Crystal Structure Determination

Related Article: J.Perez, L.Garcia, E.Perez, J.L.Serrano, J.F.Martinez, G.Sanchez, G.Lopez, A.Espinosa, M.Liu, F.Sanz|2003|New J.Chem.|27|1490|doi:10.1039/b302653a

research product

CCDC 686576: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, M.Liu|2008|Eur.J.Inorg.Chem.||4797|doi:10.1002/ejic.200800445

research product

CCDC 671663: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, I.J.S.Fairlamb, M.Liu|2008|Polyhedron|27|1699|doi:10.1016/j.poly.2008.02.001

research product

CCDC 210649: Experimental Crystal Structure Determination

Related Article: J.Perez, L.Garcia, E.Perez, J.L.Serrano, J.F.Martinez, G.Sanchez, G.Lopez, A.Espinosa, M.Liu, F.Sanz|2003|New J.Chem.|27|1490|doi:10.1039/b302653a

research product

CCDC 686575: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, M.Liu|2008|Eur.J.Inorg.Chem.||4797|doi:10.1002/ejic.200800445

research product

CCDC 671662: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, I.J.S.Fairlamb, M.Liu|2008|Polyhedron|27|1699|doi:10.1016/j.poly.2008.02.001

research product

CCDC 671664: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, I.J.S.Fairlamb, M.Liu|2008|Polyhedron|27|1699|doi:10.1016/j.poly.2008.02.001

research product

CCDC 686579: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, M.Liu|2008|Eur.J.Inorg.Chem.||4797|doi:10.1002/ejic.200800445

research product

CCDC 686580: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, M.Liu|2008|Eur.J.Inorg.Chem.||4797|doi:10.1002/ejic.200800445

research product

CCDC 686577: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, M.Liu|2008|Eur.J.Inorg.Chem.||4797|doi:10.1002/ejic.200800445

research product

CCDC 210650: Experimental Crystal Structure Determination

Related Article: J.Perez, L.Garcia, E.Perez, J.L.Serrano, J.F.Martinez, G.Sanchez, G.Lopez, A.Espinosa, M.Liu, F.Sanz|2003|New J.Chem.|27|1490|doi:10.1039/b302653a

research product

CCDC 686578: Experimental Crystal Structure Determination

Related Article: J.L.Serrano, L.Garcia, J.Perez, E.Perez, J.Garcia, G.Sanchez, G.Lopez, M.Liu|2008|Eur.J.Inorg.Chem.||4797|doi:10.1002/ejic.200800445

research product