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A precise calculation of the fundamental string tension in SU (N) gauge theories in 2 + 1 dimensions

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 645:4 (2007) 383-388

Authors:

B Bringoltz, M Teper

Abstract:

We use lattice techniques to calculate the continuum string tensions of SU (N) gauge theories in 2 + 1 dimensions. We attempt to control all systematic errors at a level that allows us to perform a precise test of the analytic prediction of Karabali, Kim and Nair. We find that their prediction is within 3% of our values for all N and that the discrepancy decreases with increasing N. When we extrapolate our results to N = ∞ we find that there remains a discrepancy of ≃ 1 %, which is a convincing ∼ 6 σ effect. Thus, while the Karabali-Nair analysis is remarkably accurate at N = ∞, it is not exact. © 2006 Elsevier B.V. All rights reserved.
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Perturbative Anti-Brane Potentials in Heterotic M-theory

(2007)

Authors:

James Gray, Andre Lukas, Burt Ovrut
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An upper limit to the photon fraction in cosmic rays above 1019 eV from the Pierre Auger Observatory

Astroparticle Physics 27:2-3 (2007) 155-168

Authors:

J Abraham, M Aglietta, C Aguirre, D Allard, I Allekotte, P Allison, C Alvarez, J Alvarez-Muñiz, M Ambrosio, L Anchordoqui, JC Anjos, C Aramo, K Arisaka, E Armengaud, F Arneodo, F Arqueros, T Asch, H Asorey, BS Atulugama, J Aublin, M Ave, G Avila, J Bacelar, T Bäcker, D Badagnani, AF Barbosa, HMJ Barbosa, M Barkhausen, D Barnhill, SLC Barroso, P Bauleo, J Beatty, T Beau, BR Becker, KH Becker, JA Bellido, S BenZvi, C Berat, T Bergmann, P Bernardini, X Bertou, PL Biermann, P Billoir, O Blanch-Bigas, F Blanco, P Blasi, C Bleve, H Blümer, P Boghrat, M Boháčová, C Bonifazi, R Bonino, M Boratav, J Brack, JM Brunet, P Buchholz, NG Busca, KS Caballero-Mora, B Cai, DV Camin, JN Capdevielle, R Caruso, A Castellina, G Cataldi, L Cazón, R Cester, J Chauvin, A Chiavassa, JA Chinellato, A Chou, J Chye, D Claes, PDJ Clark, RW Clay, SB Clay, B Connolly, A Cordier, U Cotti, S Coutu, CE Covault, J Cronin, S Dagoret-Campagne, T Dang Quang, P Darriulat, K Daumiller, BR Dawson, RM de Almeida, LA de Carvalho, C De Donato, SJ de Jong, WJM de Mello, JRT de Mello Neto, I De Mitri, MAL de Oliveira, V de Souza, L del Peral, O Deligny, A Della Selva, C Delle Fratte, H Dembinski

Abstract:

An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies greater than 1019 eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger surface detectors for a subset of the event sample support the conclusion that a photon origin of the observed events is not favored. © 2006 Elsevier B.V. All rights reserved.
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Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

Astroparticle Physics 27:4 (2007) 244-253

Authors:

J Abraham, M Aglietta, C Aguirre, D Allard, I Allekotte, P Allison, C Alvarez, J Alvarez-Muñiz, M Ambrosio, L Anchordoqui, JC Anjos, C Aramo, K Arisaka, E Armengaud, F Arneodo, F Arqueros, T Asch, H Asorey, BS Atulugama, J Aublin, M Ave, G Avila, J Bacelar, T Bäcker, D Badagnani, AF Barbosa, HMJ Barbosa, M Barkhausen, D Barnhill, SLC Barroso, P Bauleo, J Beatty, T Beau, BR Becker, KH Becker, JA Bellido, S BenZvi, C Berat, T Bergmann, P Bernardini, X Bertou, PL Biermann, P Billoir, O Blanch-Bigas, F Blanco, P Blasi, C Bleve, H Blümer, P Boghrat, M Boháčová, C Bonifazi, R Bonino, M Boratav, J Brack, JM Brunet, P Buchholz, NG Busca, KS Caballero-Mora, B Cai, DV Camin, JN Capdevielle, R Caruso, A Castellina, G Cataldi, L Cazón, R Cester, J Chauvin, A Chiavassa, JA Chinellato, A Chou, J Chye, D Claes, PDJ Clark, RW Clay, SB Clay, B Connolly, A Cordier, U Cotti, S Coutu, CE Covault, J Cronin, S Dagoret-Campagne, TD Quang, P Darriulat, K Daumiller, BR Dawson, RM de Almeida, LA de Carvalho, C De Donato, SJ de Jong, WJM de Mello, JRT de Mello Neto, I De Mitri, MAL de Oliveira, V de Souza, L del Peral, O Deligny, AD Selva, CD Fratte, H Dembinski

Abstract:

Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius A. Also the events detected simultaneously by the surface and fluorescence detectors (the 'hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction. © 2006 Elsevier B.V. All rights reserved.
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Power Corrections for Jets at Hadron Colliders

(2007)

Authors:

Lorenzo Magnea, Matteo Cacciari, Mrinal Dasgupta, Gavin Salam
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