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Search for diphoton events with large missing transverse momentum in 1 fb -1 of 7 TeV proton-proton collision data with the ATLAS detector

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 710:4-5 (2012) 519-537

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, H Abramowicz, H Abreu, E Acerbi, E Acerbi, BS Acharya, BS Acharya, DL Adams, TN Addy, J Adelman, M Aderholz, S Adomeit, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, M Ahsan, G Aielli, G Aielli, T Akdogan, TPA Åkesson, G Akimoto, AV Akimov, A Akiyama, MS Alam, MA Alam, J Albert, S Albrand, M Aleksa, IN Aleksandrov, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, M Aliyev, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, A Aloisio, R Alon, A Alonso, MG Alviggi, MG Alviggi, K Amako, P Amaral, C Amelung, VV Ammosov, A Amorim, G Amorós, N Amram, C Anastopoulos, LS Ancu, N Andari, T Andeen, CF Anders, G Anders, KJ Anderson, A Andreazza, A Andreazza, V Andrei, ML Andrieux, XS Anduaga, A Angerami, F Anghinolfi, N Anjos, A Annovi, A Antonaki, M Antonelli, A Antonov, J Antos, F Anulli, S Aoun, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault, S Arfaoui, JF Arguin, E Arik, M Arik

Abstract:

A search for diphoton events with large missing transverse momentum has been performed using 1.07 fb -1 of proton-proton collision data at s=7 TeV recorded with the ATLAS detector. No excess of events was observed above the Standard Model prediction and 95% Confidence Level (CL) upper limits are set on the production cross section for new physics. The limits depend on each model parameter space and vary as follows: Λ<(22-129) fb in the context of a generalised model of gauge-mediated supersymmetry breaking (GGM) with a bino-like lightest neutralino, σ<(27-91) fb in the context of a minimal model of gauge-mediated supersymmetry breaking (SPS8), and σ<(15-27) fb in the context of a specific model with one universal extra dimension (UED). A 95% CL lower limit of 805 GeV, for bino masses above 50 GeV, is set on the GGM gluino mass. Lower limits of 145 TeV and 1.23 TeV are set on the SPS8 breaking scale Λ and on the UED compactification scale 1/R, respectively. These limits provide the most stringent tests of these models to date. © 2012 CERN.

Search for extra dimensions using diphoton events in 7 TeV proton-proton collisions with the ATLAS detector

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 710:4-5 (2012) 538-556

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, OS AbouZeid, H Abramowicz, H Abreu, E Acerbi, E Acerbi, BS Acharya, BS Acharya, L Adamczyk, DL Adams, TN Addy, J Adelman, M Aderholz, S Adomeit, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, M Ahsan, G Aielli, G Aielli, T Akdogan, TPA Åkesson, G Akimoto, AV Akimov, A Akiyama, MS Alam, MA Alam, J Albert, S Albrand, M Aleksa, IN Aleksandrov, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, M Aliyev, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, A Aloisio, R Alon, A Alonso, B Alvarez Gonzalez, MG Alviggi, MG Alviggi, K Amako, P Amaral, C Amelung, VV Ammosov, A Amorim, G Amorós, N Amram, C Anastopoulos, LS Ancu, N Andari, T Andeen, CF Anders, G Anders, KJ Anderson, A Andreazza, A Andreazza, V Andrei, ML Andrieux, XS Anduaga, A Angerami, F Anghinolfi, A Anisenkov, N Anjos, A Annovi, A Antonaki, M Antonelli, A Antonov, J Antos, F Anulli, S Aoun, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault

Abstract:

Using data recorded in 2011 with the ATLAS detector at the Large Hadron Collider, a search for evidence of extra spatial dimensions has been performed through an analysis of the diphoton final state. The analysis uses data corresponding to an integrated luminosity of 2.12fb-1 of s=7TeV proton-proton collisions. The diphoton invariant mass (mγγ) spectrum is observed to be in good agreement with the expected Standard Model background. In the large extra dimension scenario of Arkani-Hamed, Dimopoulos and Dvali, the results provide 95% CL lower limits on the fundamental Planck scale between 2.27 and 3.53 TeV, depending on the number of extra dimensions and the theoretical formalism used. The results also set 95% CL lower limits on the lightest Randall-Sundrum graviton mass of between 0.79 and 1.85 TeV, for values of the dimensionless coupling k/-1 Pl varying from 0.01 to 0.1. Combining with previously published ATLAS results from the dielectron and dimuon final states, the 95% CL lower limit on the Randall-Sundrum graviton mass for k/M-1Pl=0.01 (0.1) is 0.80 (1.95) TeV. © 2012 CERN.

Wide-band Simultaneous Observations of Pulsars: Disentangling Dispersion Measure and Profile Variations

(2012)

Authors:

TE Hassall, BW Stappers, JWT Hessels, M Kramer, A Alexov, K Anderson, T Coenen, A Karastergiou, EF Keane, VI Kondratiev, K Lazaridis, J van Leeuwen, A Noutsos, M Serylak, C Sobey, JPW Verbiest, P Weltevrede, K Zagkouris, R Fender, RAMJ Wijers, L Bahren, ME Bell, JW Broderick, S Corbel, EJ Daw, VS Dhillon, J Eisloffel, H Falcke, J-M Griessmeier, P Jonker, C Law, S Markoff, JCA Miller-Jones, R Osten, E Rol, AMM Scaife, B Scheers, P Schellart, H Spreeuw, J Swinbank, S ter Veen, MW Wise, R Wijnands, O Wucknitz, P Zarka, A Asgekar, MR Bell, MJ Bentum, G Bernardi, P Best, A Bonafede, AJ Boonstra, M Brentjens, WN Brouw, M Bruggen, HR Butcher, B Ciardi, MA Garrett, M Gerbers, AW Gunst, MP van Haarlem, G Heald, M Hoeft, H Holties, A de Jong, LVE Koopmans, M Kuniyoshi, G Kuper, GM Loose, P Maat, J Masters, JP McKean, H Meulman, M Mevius, H Munk, JE Noordam, E Orru, H Paas, M Pandey-Pommier, VN Pandey, R Pizzo, A Polatidis, W Reich, H Rottgering, J Sluman, M Steinmetz, CGM Sterks, M Tagger, Y Tang, C Tasse, R Vermeulen, RJ van Weeren, SJ Wijnholds, S Yatawatta

Halo abundances and shear in void models

(2012)

Authors:

David Alonso, Juan García-Bellido, Troels Haugboelle, Alexander Knebe

Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts

Astronomy and Astrophysics 540 (2012)

Authors:

J Abadie, BP Abbott, R Abbott, TD Abbott, M Abernathy, T Accadia, F Acernese, C Adams, R Adhikari, C Affeldt, M Agathos, P Ajith, B Allen, GS Allen, E Amador Ceron, D Amariutei, RS Amin, SB Anderson, WG Anderson, K Arai, MA Arain, MC Araya, SM Aston, P Astone, D Atkinson, P Aufmuth, C Aulbert, BE Aylott, S Babak, P Baker, G Ballardin, S Ballmer, D Barker, F Barone, B Barr, P Barriga, L Barsotti, M Barsuglia, MA Barton, I Bartos, R Bassiri, M Bastarrika, A Basti, J Batch, J Bauchrowitz, TS Bauer, M Bebronne, B Behnke, MG Beker, AS Bell, A Belletoile, I Belopolski, M Benacquista, JM Berliner, A Bertolini, J Betzwieser, N Beveridge, PT Beyersdorf, IA Bilenko, G Billingsley, J Birch, R Biswas, M Bitossi, MA Bizouard, E Black, JK Blackburn, L Blackburn, D Blair, B Bland, M Blom, O Bock, TP Bodiya, C Bogan, R Bondarescu, F Bondu, L Bonelli, R Bonnand, R Bork, M Born, V Boschi, S Bose, L Bosi, B Bouhou, S Braccini, C Bradaschia, PR Brady, VB Braginsky, M Branchesi, JE Brau, J Breyer, T Briant, DO Bridges, A Brillet, M Brinkmann, V Brisson, M Britzger, AF Brooks, DA Brown, A Brummit, T Bulik

Abstract:

Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with ∼ 50% or better probability with a few pointings of wide-field telescopes. © 2012 ESO.