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The metamorphosis of supernova SN 2008D/XRF 080109: A link between supernovae and GRBs/hypernovae

Science 321:5893 (2008) 1185-1188

Authors:

PA Mazzali, S Valenti, M Della Valle, G Chincarini, DN Sauer, S Benetti, E Pian, T Piran, V D'Elia, N Elias-Rosa, R Margutti, F Pasotti, LA Antonelli, F Bufano, S Campana, E Cappellaro, S Covino, P D'Avanzo, F Fiore, D Fugazza, R Gilmozzi, D Hunter, K Maguire, E Maiorano, P Marziani, N Masetti, F Mirabel, H Navasardyan, K Nomoto, E Palazzi, A Pastorello, N Panagia, LJ Pellizza, R Sari, S Smartt, G Tagliaferri, M Tanaka, S Taubenberger, N Tominaga, C Trundle, M Turatto

Abstract:

The only supernovae (SNe) to show gamma-ray bursts (GRBs) or early x-ray emission thus far are overenergetic, broad-lined type Ic SNe (hypernovae, HNe). Recently, SN 2008D has shown several unusual features: (i) weak x-ray flash (XRF), (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SN Ic HNe, and (iv) development of helium lines as in SNe Ib. Detailed analysis shows that SN 2008D was not a normal supernova: Its explosion energy (E ≈ 6 × 1051 erg) and ejected mass [∼7 times the mass of the Sun (MFish eye)] are intermediate between normal SNe Ibc and HNe. We conclude that SN 2008D was originally a ∼30 M Fish eye star. When it collapsed, a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes.
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Search for heavy, long-lived neutralinos that decay to photons at CDF II using photon timing

Physical Review D Particles Fields Gravitation and Cosmology 78:3 (2008)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, BA González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzurri, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, P Bednar, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, A Clark, D Clark, G Compostella

Abstract:

We present the results of the first hadron collider search for heavy, long-lived neutralinos that decay via χ10→γG in gauge-mediated supersymmetry breaking models. Using an integrated luminosity of 570±34pb-1 of pp̄ collisions at s=1.96TeV, we select γ+jet+missing transverse energy candidate events based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed on the CDF II detector. We find 2 events, consistent with the background estimate of 1.3±0.7 events. While our search strategy does not rely on model-specific dynamics, we set cross section limits and place the world-best 95% C.L. lower limit on the χ 10 mass of 101GeV/c2 at τχ 10=5ns. © 2008 The American Physical Society.
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Erratum: Search for pair production of scalar top quarks decaying to a τ Lepton and a b quark in pp̄ collisions at s=1.96TeV (Physical Review Letters (2008) 101 (071802))

Physical Review Letters 101:8 (2008)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, B Alvarez Gonzalez, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, M Aoki, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, P Bednar, S Behari, G Bellettini, J Bellinger, A Belloni, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, CI Ciobanu
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Inclusive radiative J/ψ decays

Physical Review D Particles Fields Gravitation and Cosmology 78:3 (2008)

Authors:

D Besson, TK Pedlar, D Cronin-Hennessy, KY Gao, J Hietala, Y Kubota, T Klein, BW Lang, R Poling, AW Scott, P Zweber, S Dobbs, Z Metreveli, KK Seth, A Tomaradze, J Libby, A Powell, G Wilkinson, KM Ecklund, W Love, V Savinov, H Mendez, JY Ge, DH Miller, IPJ Shipsey, B Xin, GS Adams, M Anderson, JP Cummings, I Danko, D Hu, B Moziak, J Napolitano, Q He, J Insler, H Muramatsu, CS Park, EH Thorndike, F Yang, M Artuso, S Blusk, S Khalil, J Li, R Mountain, S Nisar, K Randrianarivony, N Sultana, T Skwarnicki, S Stone, JC Wang, LM Zhang, G Bonvicini, D Cinabro, M Dubrovin, A Lincoln, P Naik, J Rademacker, DM Asner, KW Edwards, J Reed, RA Briere, T Ferguson, G Tatishvili, H Vogel, ME Watkins, JL Rosner, JP Alexander, DG Cassel, JE Duboscq, R Ehrlich, L Fields, RS Galik, L Gibbons, R Gray, SW Gray, DL Hartill, BK Heltsley, D Hertz, JM Hunt, J Kandaswamy, DL Kreinick, VE Kuznetsov, J Ledoux, H Mahlke-Krüger, D Mohapatra, PUE Onyisi, JR Patterson, D Peterson, D Riley, A Ryd, AJ Sadoff, X Shi, S Stroiney, WM Sun, T Wilksen, SB Athar, R Patel, J Yelton, P Rubin, BI Eisenstein

Abstract:

Using data taken with the CLEO-c detector at the Cornell Electron Storage Ring, we have investigated the direct-photon momentum spectrum in the decay J/ψ(1S)→γgg, via the "tagged" process: e+e-→ψ(2S); ψ(2S)→J/ψπ+π-; J/ψ→γ+X. Including contributions from two-body radiative decay processes, we find the ratio of the inclusive direct-photon branching fraction to that of the dominant three-gluon branching fraction [Rγ=B(ggγ)/B(ggg)] to be Rγ=0.137±0.001±0.016±0.004, where the errors shown are statistical, systematic, and the model-dependent uncertainty related to the extrapolation to zero photon energy. The shape of the scaled photon energy spectrum in J/ψ→ggγ is observed to be very similar to that of Υ→ggγ. The Rγ value obtained is roughly consistent with that expected by a simple quark-charge scaling [Rγ∼(qc/qb)2] of the value determined at the Υ(1S), but somewhat higher than the value expected from the running of the strong coupling constant. © 2008 The American Physical Society.
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Measurement of exclusive baryon-antibaryon decays of χcJ mesons

Physical Review D Particles Fields Gravitation and Cosmology 78:3 (2008)

Authors:

P Naik, J Rademacker, DM Asner, KW Edwards, J Reed, RA Briere, T Ferguson, G Tatishvili, H Vogel, ME Watkins, JL Rosner, JP Alexander, DG Cassel, JE Duboscq, R Ehrlich, L Fields, L Gibbons, R Gray, SW Gray, DL Hartill, BK Heltsley, D Hertz, JM Hunt, J Kandaswamy, DL Kreinick, VE Kuznetsov, J Ledoux, H Mahlke-Krüger, D Mohapatra, PUE Onyisi, JR Patterson, D Peterson, D Riley, A Ryd, AJ Sadoff, X Shi, S Stroiney, WM Sun, T Wilksen, SB Athar, R Patel, J Yelton, P Rubin, BI Eisenstein, I Karliner, S Mehrabyan, N Lowrey, M Selen, EJ White, J Wiss, RE Mitchell, MR Shepherd, D Besson, TK Pedlar, D Cronin-Hennessy, KY Gao, J Hietala, Y Kubota, T Klein, BW Lang, R Poling, AW Scott, P Zweber, S Dobbs, Z Metreveli, KK Seth, A Tomaradze, J Libby, A Powell, G Wilkinson, KM Ecklund, W Love, V Savinov, H Mendez, JY Ge, DH Miller, IPJ Shipsey, B Xin, GS Adams, M Anderson, JP Cummings, I Danko, D Hu, B Moziak, J Napolitano, Q He, J Insler, H Muramatsu, CS Park, EH Thorndike, F Yang, M Artuso, S Blusk, S Khalil, J Li, R Mountain, S Nisar, K Randrianarivony, N Sultana, T Skwarnicki

Abstract:

Using a sample of 2.59×107 ψ(2S) decays collected by the CLEO-c detector, we present results of a study of χcJ (J=0, 1, 2) decays into baryon-antibaryon final states. We present the world's most precise measurements of the χcJ→pp̄ and χcJ→ΛΛ̄ branching fractions, and the first measurements of χc0 decays to other hyperons. These results illuminate the decay mechanism of the χc states. © 2008 The American Physical Society.
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