Study of Z production in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV in the dimuon and dielectron decay channels

ArXiv 1410.4825 (2014)

HERAFitter, Open Source QCD Fit Project

(2014)

Authors:

S Alekhin, O Behnke, P Belov, S Borroni, M Botje, D Britzger, S Camarda, AM Cooper-Sarkar, K Daum, C Diaconu, J Feltesse, A Gizhko, A Glazov, A Guffanti, M Guzzi, F Hautmann, A Jung, H Jung, V Kolesnikov, H Kowalski, O Kuprash, A Kusina, S Levonian, K Lipka, B Lobodzinski, K Lohwasser, A Luszczak, B Malaescu, R McNulty, V Myronenko, S Naumann-Emme, K Nowak, F Olness, E Perez, H Pirumov, R Placakyte, K Rabbertz, V Radescu, R Sadykov, GP Salam, A Sapronov, A Schoening, T Schoerner-Sadenius, S Shushkevich, W Slominski, H Spiesberger, P Starovoitov, M Sutton, J Tomaszewska, O Turkot, A Vargas, G Watt, K Wichmann

Search for the direct production of charginos, neutralinos and staus in final states with at least two hadronically decaying taus and missing transverse momentum in pp collisions at √s = 8 TeV with the ATLAS detector

Journal of High Energy Physics 2014:10 (2014)

Authors:

G Aad, B Abbott, J Abdallah, S Abdel Khalek, O Abdinov, R Aben, B Abi, M Abolins, OS Abouzeid, H Abramowicz, H Abreu, R Abreu, Y Abulaiti, BS Acharya, L Adamczyk, DL Adams, J Adelman, S Adomeit, T Adye, T Agatonovic-Jovin, JA Aguilar-Saavedra, M Agustoni, SP Ahlen, F Ahmadov, G Aielli, H Akerstedt, TPA Åkesson, G Akimoto, AV Akimov, GL Alberghi, J Albert, S Albrand, MJ Alconada Verzini, M Aleksa, IN Aleksandrov, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, G Alimonti, L Alio, J Alison, BMM Allbrooke, LJ Allison, PP Allport, J Almond, A Aloisio, A Alonso, F Alonso, C Alpigiani, A Altheimer, B Alvarez Gonzalez, MG Alviggi, K Amako, Y Amaral Coutinho, C Amelung, D Amidei, SP Amor Dos Santos, A Amorim, S Amoroso, N Amram, G Amundsen, C Anastopoulos, LS Ancu, N Andari, T Andeen, CF Anders, G Anders, KJ Anderson, A Andreazza, V Andrei, XS Anduaga, S Angelidakis, I Angelozzi, P Anger, A Angerami, F Anghinolfi, AV Anisenkov, N Anjos, A Annovi, A Antonaki, M Antonelli, A Antonov, J Antos, F Anulli, M Aoki, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, JP Araque, ATH Arce, JF Arguin, S Argyropoulos, M Arik, AJ Armbruster, O Arnaez, V Arnal

Abstract:

Results of a search for the electroweak associated production of charginos and next-to-lightest neutralinos, pairs of charginos or pairs of tau sleptons are presented. These processes are characterised by final states with at least two hadronically decaying tau leptons, missing transverse momentum and low jet activity. The analysis is based on an integrated luminosity of 20.3 fb-1of proton-proton collisions at √s = 8TeV recorded with the ATLAS experiment at the Large Hadron Collider. No significant excess is observed with respect to the predictions from Standard Model processes. Limits are set at 95% confidence level on the masses of the lighter chargino and next-to-lightest neutralino for various hypotheses for the lightest neutralino mass in simplified models. In the scenario of direct production of chargino pairs, with each chargino decaying into the lightest neutralino via an intermediate tau slepton, chargino masses up to 345 GeV are excluded for a massless lightest neutralino. For associated production of mass-degenerate charginos and next-tolightest neutralinos, both decaying into the lightest neutralino via an intermediate tau slepton, masses up to 410 GeV are excluded for a massless lightest neutralino.

Identification techniques for highly boosted W bosons that decay into hadrons

ArXiv 1410.4227 (2014)

Measurements of normalized differential cross sections for t¯t production in pp collisions at √(s) = 7 TeV using the ATLAS detector

Physical Review D - Particles, Fields, Gravitation and Cosmology 90:7 (2014)

Authors:

G Aad, T Abajyan, B Abbott, J Abdallah, S Abdel Khalek, O Abdinov, R Aben, B Abi, M Abolins, OS AbouZeid, H Abramowicz, H Abreu, Y Abulaiti, BS Acharya, L Adamczyk, DL Adams, J Adelman, S Adomeit, T Adye, T Agatonovic-Jovin, JA Aguilar-Saavedra, M Agustoni, SP Ahlen, F Ahmadov, G Aielli, TPA Åkesson, G Akimoto, AV Akimov, J Albert, S Albrand, MJ Alconada Verzini, M Aleksa, IN Aleksandrov, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, G Alimonti, L Alio, J Alison, BMM Allbrooke, LJ Allison, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, F Alonso, C Alpigiani, A Altheimer, B Alvarez Gonzalez, MG Alviggi, K Amako, Y Amaral Coutinho, C Amelung, D Amidei, VV Ammosov, SP Amor Dos Santos, A Amorim, S Amoroso, N Amram, G Amundsen, C Anastopoulos, LS Ancu, N Andari, T Andeen, CF Anders, G Anders, KJ Anderson, A Andreazza, V Andrei, XS Anduaga, S Angelidakis, P Anger, A Angerami, F Anghinolfi, AV Anisenkov, N Anjos, A Annovi, A Antonaki, M Antonelli, A Antonov, J Antos, F Anulli, M Aoki, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, JP Araque, ATH Arce, JF Arguin, S Argyropoulos, M Arik, AJ Armbruster, O Arnaez, V Arnal

Abstract:

Measurements of normalized differential cross sections for top-quark pair production are presented as a function of the top-quark transverse momentum, and of the mass, transverse momentum, and rapidity of the t¯t system, in proton-proton collisions at a center-of-mass energy of √s = 7 TeV. The data set corresponds to an integrated luminosity of 4.6 fb-1, recorded in 2011 with the ATLAS detector at the CERN Large Hadron Collider. Events are selected in the lepton + jets channel, requiring exactly one lepton and at least four jets with at least one of the jets tagged as originating from a b-quark. The measured spectra are corrected for detector efficiency and resolution effects and are compared to several Monte Carlo simulations and theory calculations. The results are in fair agreement with the predictions in a wide kinematic range. Nevertheless, data distributions are softer than predicted for higher values of the mass of the t¯t system and of the top-quark transverse momentum. The measurements can also discriminate among different sets of parton distribution functions.