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Search for pair production of light scalar top quarks in pp collisions at √s = 1.8 TeV

Physical Review Letters 93:1 (2004)

Authors:

VM Abazov, B Abbott, A Abdesselam, M Abolins, V Abramov, BS Acharya, DL Adams, M Adams, SN Ahmed, GD Alexeev, A Alton, GA Alves, Y Arnoud, C Avila, VV Babintsev, L Babukhadia, TC Bacon, A Baden, S Baffioni, B Baldin, PW Balm, S Banerjee, E Barberis, P Baringer, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, F Beaudette, M Begel, A Belyaev, SB Beri, G Bernardi, I Bertram, A Besson, R Beuselinck, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, G Blazey, F Blekman, S Blessing, A Boehnlein, NI Bojko, TA Bolton, F Borcherding, K Bos, T Bose, A Brandt, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, M Buehler, V Buescher, VS Burtovoi, JM Butler, F Canelli, W Carvalho, D Casey, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, DK Cho, S Choi, S Chopra, D Claes, AR Clark, B Connolly, WE Cooper, D Coppage, S Crépé-Renaudin, MAC Cummings, D Cutts, H da Motta, GA Davis, K De, SJ de Jong, M Demarteau, R Demina, P Demine, D Denisov, SP Denisov, S Desai, HT Diehl, M Diesburg, S Doulas, LV Dudko, L Duflot, SR Dugad, A Duperrin, A Dyshkant, D Edmunds, J Ellison, JT Eltzroth, VD Elvira

Abstract:

The results of a search for direct pair production of scalar top quarks (t̃), the supersymmetric partners of the top quark were presented. Events containing two or more jets and missing transverse energy, the signature of light scalar top quark decays to charm quarks and neutralinos were investigated. 27 events were observed after the selection, while expecting 31.1±6.4 events from known standard model processes. The results were compared to next-to-leading-order production cross sections, and a significant region of t̃ and neutralino phase space was excluded.
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Evidence for a narrow baryonic state decaying to KS0p and KS0p̄ in deep inelastic scattering at HERA

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 591:1-2 (2004) 7-22

Authors:

S Chekanov, M Derrick, JH Loizides, S Magill, S Miglioranzi, B Musgrave, J Repond, R Yoshida, MCK Mattingly, N Pavel, P Antonioli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, G Cara Romeo, L Cifarelli, F Cindolo, A Contin, M Corradi, S de Pasquale, P Giusti, G Iacobucci, A Margotti, A Montanari, R Nania, F Palmonari, A Pesci, L Rinaldi, G Sartorelli, A Zichichi, G Aghuzumtsyan, D Bartsch, I Brock, S Goers, H Hartmann, E Hilger, P Irrgang, HP Jakob, O Kind, U Meyer, E Paul, J Rautenberg, R Renner, A Stifutkin, J Tandler, KC Voss, M Wang, DS Bailey, NH Brook, JE Cole, GP Heath, T Namsoo, S Robins, M Wing, M Capua, A Mastroberardino, M Schioppa, G Susinno, JY Kim, IT Lim, KJ Ma, MY Pac, M Helbich, Y Ning, Z Ren, WB Schmidke, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, K Olkiewicz, P Stopa, L Zawiejski, L Adamczyk, T Bold, I Grabowska-Bold, D Kisielewska, AM Kowal, M Kowal, J Łukasik, M Przybycień, L Suszycki, D Szuba, J Szuba, A Kotański, W Slomiński, V Adler, U Behrens, I Bloch, K Borras, V Chiochia, D Dannheim, G Drews, J Fourletova, U Fricke, A Geiser

Abstract:

A resonance search has been made in the K0Sp and K0Sp̄ invariant-mass spectrum measured with the ZEUS detector at HERA using an integrated luminosity of 121 pb-1. The search was performed in the central rapidity region of inclusive deep inelastic scattering at an ep centre-of-mass energy of 300-318 GeV for exchanged photon virtuality, Q2, above 1 GeV2. Recent results from fixed-target experiments give evidence for a narrow baryon resonance decaying to K+n and K0Sp, interpreted as a pentaquark. The results presented here support the existence of such state, with a mass of 1521.5±1.5(stat.)+2.8-1.7(syst.) MeV and a Gaussian width consistent with the experimental resolution of 2 MeV. The signal is visible at high Q2 and, for Q2>20 GeV2, contains 221±48 events. The probability of a similar signal anywhere in the range 1500-1560 MeV arising from fluctuations of the background is below 6×10-5. © 2004 Elsevier B.V. All rights reserved.
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Search for contact interactions, large extra dimensions and finite quark radius in ep collisions at HERA

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 591:1-2 (2004) 23-41

Authors:

S Chekanov, M Derrick, D Krakauer, JH Loizides, S Magill, S Miglioranzi, B Musgrave, J Repond, R Yoshida, MCK Mattingly, P Antonioli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, G Cara Romeo, L Cifarelli, F Cindolo, A Contin, M Corradi, S de Pasquale, P Giusti, G Iacobucci, A Margotti, A Montanari, R Nania, F Palmonari, A Pesci, G Sartorelli, A Zichichi, G Aghuzumtsyan, D Bartsch, I Brock, S Goers, H Hartmann, E Hilger, P Irrgang, HP Jakob, O Kind, U Meyer, E Paul, J Rautenberg, R Renner, A Stifutkin, J Tandler, KC Voss, M Wang, A Weber, DS Bailey, NH Brook, JE Cole, GP Heath, T Namsoo, S Robins, M Wing, M Capua, A Mastroberardino, M Schioppa, G Susinno, JY Kim, YK Kim, JH Lee, IT Lim, MY Pac, A Caldwell, M Helbich, X Liu, B Mellado, Y Ning, S Paganis, Z Ren, WB Schmidke, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, K Olkiewicz, P Stopa, L Zawiejski, L Adamczyk, T Bold, I Grabowska-Bold, D Kisielewska, AM Kowal, M Kowal, T Kowalski, M Przybycien, L Suszycki, D Szuba, J Szuba, A Kotański, W Slomiński, V Adler, U Behrens, I Bloch, K Borras, V Chiochia

Abstract:

A search for physics beyond the Standard Model has been performed with high-Q2 neutral current deep inelastic scattering events recorded with the ZEUS detector at HERA. Two data sets, e+p→e +X and e-p→e-X, with respective integrated luminosities of 112 pb-1 and 16 pb-1, were analyzed. The data reach Q2 values as high as 40000 GeV2. No significant deviations from Standard Model predictions were observed. Limits were derived on the effective mass scale in eeqq contact interactions, the ratio of leptoquark mass to the Yukawa coupling for heavy leptoquark models and the mass scale parameter in models with large extra dimensions. The limit on the quark charge radius, in the classical form factor approximation, is 0.85×10 -16 cm. © 2004 Published by Elsevier B.V.
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First Measurements of Inclusive W and Z Cross Sections from Run II of the Tevatron Collider

ArXiv hep-ex/0406078 (2004)
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Search for Doubly-Charged Higgs Bosons Decaying to Dileptons in ppbar Collisions at sqrt(s)=1.96 TeV

ArXiv hep-ex/0406073 (2004)

Authors:

CDF Collaboration, D Acosta
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