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.

First Measurements of Inclusive W and Z Cross Sections from Run II of the Tevatron Collider

ArXiv hep-ex/0406078 (2004)

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

Photoproduction of D*± mesons associated with a leading neutron

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 590:3-4 (2004) 143-160

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 Przybycień, L Suszycki, D Szuba, J Szuba, A Kotański, W Slomiński, V Adler, U Behrens, I Bloch, K Borras, V Chiochia

Abstract:

The photoproduction of D(2010) mesons associated with a leading neutron has been observed with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 80 pb-1. The neutron carries a large fraction, xL>0.2, of the incoming proton beam energy and is detected at very small production angles, θn< 0.8 mrad, an indication of peripheral scattering. The D* meson is centrally produced with pseudorapidity η<1.5, and has a transverse momentum pT>1.9 GeV, which is large compared to the average transverse momentum of the neutron of 0.22 GeV. The ratio of neutron-tagged to inclusive D* production is 8.85±0.93(stat.) +0.48-0.61(syst.)% in the photon-proton center-of-mass energy range 130

A precision measurement of the mass of the top quark.

Nature 429:6992 (2004) 638-642

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, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, J Estrada, H Evans, VN Evdokimov, T Ferbel, F Filthaut, HE Fisk, M Fortner, H Fox, S Fu, S Fuess, E Gallas, AN Galyaev, M Gao, V Gavrilov, RJ Genik, K Genser, CE Gerber, Y Gershtein, G Ginther, B Gómez, PI Goncharov, K Gounder, A Goussiou, PD Grannis, H Greenlee, ZD Greenwood, S Grinstein, L Groer, S Grünendahl, MW Grünewald, SN Gurzhiev, G Gutierrez, P Gutierrez, NJ Hadley, H Haggerty, S Hagopian, V Hagopian, RE Hall, C Han, S Hansen, JM Hauptman, C Hebert, D Hedin, JM Heinmiller, AP Heinson, U Heintz, MD Hildreth, R Hirosky, JD Hobbs, B Hoeneisen, J Huang, Y Huang, I Iashvili, R Illingworth, AS Ito, M Jaffré, S Jain, R Jesik, K Johns, M Johnson, A Jonckheere, H Jöstlein, A Juste, W Kahl, S Kahn, E Kajfasz, AM Kalinin, D Karmanov, D Karmgard, R Kehoe, S Kesisoglou, A Khanov, A Kharchilava, B Klima, JM Kohli, AV Kostritskiy, J Kotcher, B Kothari, AV Kozelov, EA Kozlovsky, J Krane, MR Krishnaswamy, P Krivkova, S Krzywdzinski, M Kubantsev, S Kuleshov, Y Kulik, S Kunori, A Kupco, VE Kuznetsov, G Landsberg, WM Lee, A Leflat, F Lehner, C Leonidopoulos, J Li, QZ Li, JGR Lima, D Lincoln, SL Linn, J Linnemann, R Lipton, A Lucotte, L Lueking, C Lundstedt, C Luo, AKA Maciel, RJ Madaras, VL Malyshev, V Manankov, HS Mao, T Marshall, MI Martin, SEK Mattingly, AA Mayorov, R McCarthy, T McMahon, HL Melanson, A Melnitchouk, A Merkin, KW Merritt, C Miao, H Miettinen, D Mihalcea, N Mokhov, NK Mondal, HE Montgomery, RW Moore, YD Mutaf, E Nagy, M Narain, VS Narasimham, NA Naumann, HA Neal, JP Negret, S Nelson, A Nomerotski, T Nunnemann, D O'Neil, V Oguri, N Oshima, P Padley, K Papageorgiou, N Parashar, R Partridge, N Parua, A Patwa, O Peters, P Pétroff, R Piegaia, BG Pope, HB Prosper, S Protopopescu, MB Przybycien, J Qian, S Rajagopalan, PA Rapidis, NW Reay, S Reucroft, M Ridel, M Rijssenbeek, F Rizatdinova, T Rockwell, C Royon, P Rubinov, R Ruchti, BM Sabirov, G Sajot, A Santoro, L Sawyer, RD Schamberger, H Schellman, A Schwartzman, E Shabalina, RK Shivpuri, D Shpakov, M Shupe, RA Sidwell, V Simak, V Sirotenko, P Slattery, RP Smith, GR Snow, J Snow, S Snyder, J Solomon, Y Song, V Sorín, M Sosebee, N Sotnikova, K Soustruznik, M Souza, NR Stanton, G Steinbrück, D Stoker, V Stolin, A Stone, DA Stoyanova, MA Strang, M Strauss, M Strovink, L Stutte, A Sznajder, M Talby, W Taylor, S Tentindo-Repond, TG Trippe, AS Turcot, PM Tuts, R Van Kooten, V Vaniev, N Varelas, F Villeneuve-Seguier, AA Volkov, AP Vorobiev, HD Wahl, Z-M Wang, J Warchol, G Watts, M Wayne, H Weerts, A White, D Whiteson, DA Wijngaarden, S Willis, SJ Wimpenny, J Womersley, DR Wood, Q Xu, R Yamada, T Yasuda, YA Yatsunenko, K Yip, J Yu, M Zanabria, X Zhang, B Zhou, Z Zhou, M Zielinski, D Zieminska, A Zieminski, V Zutshi, EG Zverev, A Zylberstejn, DØ Collaboration

Abstract:

The standard model of particle physics contains parameters--such as particle masses--whose origins are still unknown and which cannot be predicted, but whose values are constrained through their interactions. In particular, the masses of the top quark (M(t)) and W boson (M(W)) constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of M(t) can therefore indicate where to look for the Higgs, and indeed whether the hypothesis of a standard model Higgs is consistent with experimental data. As top quarks are produced in pairs and decay in only about 10(-24) s into various final states, reconstructing their masses from their decay products is very challenging. Here we report a technique that extracts more information from each top-quark event and yields a greatly improved precision (of +/- 5.3 GeV/c2) when compared to previous measurements. When our new result is combined with our published measurement in a complementary decay mode and with the only other measurements available, the new world average for M(t) becomes 178.0 +/- 4.3 GeV/c2. As a result, the most likely Higgs mass increases from the experimentally excluded value of 96 to 117 GeV/c2, which is beyond current experimental sensitivity. The upper limit on the Higgs mass at the 95% confidence level is raised from 219 to 251 GeV/c2.