Search for single-top-quark production in pp¯ collisions at s=1.8 TeV

Physical Review D American Physical Society (APS) 65:9 (2002) 091102

Authors:

D Acosta, T Affolder, H Akimoto, MG Albrow, P Amaral, D Ambrose, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, E Brubaker, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, S Cabrera, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, W Caskey, A Castro, D Cauz, A Cerri, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, M-T Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, JY Chung, YS Chung, CI Ciobanu, AG Clark, AP Colijn, A Connolly, M Convery, J Conway, M Cordelli, J Cranshaw, R Culbertson, D Dagenhart, S D’Auria, F DeJongh, S Dell’Agnello, M Dell’Orso, S Demers, L Demortier, M Deninno, PF Derwent, T Devlin, JR Dittmann, A Dominguez, S Donati, J Done, M D’Onofrio, T Dorigo, N Eddy, K Einsweiler, JE Elias, E Engels, R Erbacher, D Errede, S Errede, Q Fan, H-C Fang, RG Feild, JP Fernandez, C Ferretti, RD Field, I Fiori, B Flaugher, GW Foster, M Franklin, J Freeman, J Friedman, Y Fukui, I Furic, S Galeotti, A Gallas, M Gallinaro, T Gao, M Garcia-Sciveres, AF Garfinkel, P Gatti, C Gay, DW Gerdes, P Giannetti, MP Giordani, P Giromini, V Glagolev, D Glenzinski, M Gold, J Goldstein, I Gorelov, AT Goshaw, Y Gotra, K Goulianos, C Green, G Grim, P Gris, C Grosso-Pilcher, M Guenther, G Guillian, J Guimaraes da Costa, RM Haas, C Haber, SR Hahn, C Hall, T Handa, R Handler, W Hao, F Happacher, K Hara, AD Hardman, RM Harris, F Hartmann, K Hatakeyama, J Hauser, J Heinrich, A Heiss, M Herndon, C Hill, A Hocker, KD Hoffman, R Hollebeek, L Holloway, BT Huffman, R Hughes, J Huston, J Huth, H Ikeda, J Incandela, G Introzzi, A Ivanov, J Iwai, Y Iwata, E James, M Jones, U Joshi, H Kambara, T Kamon, T Kaneko, M Karagoz Unel, K Karr, S Kartal, H Kasha, Y Kato, TA Keaffaber, K Kelley, M Kelly, D Khazins, T Kikuchi, B Kilminster, BJ Kim, DH Kim, HS Kim, MJ Kim, SB Kim, SH Kim, YK Kim, M Kirby, M Kirk, L Kirsch, S Klimenko, P Koehn, K Kondo, J Konigsberg, A Korn, A Korytov, E Kovacs, J Kroll, M Kruse, SE Kuhlmann, K Kurino, T Kuwabara, AT Laasanen, N Lai, S Lami, S Lammel, J Lancaster, M Lancaster, R Lander, A Lath, G Latino, T LeCompte, K Lee, S Leone, JD Lewis, M Lindgren, TM Liss, JB Liu, YC Liu, DO Litvintsev, O Lobban, NS Lockyer, J Loken, M Loreti, D Lucchesi, P Lukens, S Lusin, L Lyons, J Lys, R Madrak, K Maeshima, P Maksimovic, L Malferrari, M Mangano, M Mariotti, G Martignon, A Martin, JAJ Matthews, P Mazzanti, KS McFarland, P McIntyre, M Menguzzato, A Menzione, P Merkel, C Mesropian, A Meyer, T Miao, R Miller, JS Miller, H Minato, S Miscetti, M Mishina, G Mitselmakher, Y Miyazaki, N Moggi, E Moore, R Moore, Y Morita, T Moulik, M Mulhearn, A Mukherjee, T Muller, A Munar, P Murat, S Murgia, J Nachtman, V Nagaslaev, S Nahn, H Nakada, I Nakano, C Nelson, T Nelson, C Neu, D Neuberger, C Newman-Holmes, C-YP Ngan, H Niu, L Nodulman, A Nomerotski, SH Oh, YD Oh, T Ohmoto, T Ohsugi, R Oishi, T Okusawa, J Olsen, W Orejudos, C Pagliarone, F Palmonari, R Paoletti, V Papadimitriou, D Partos, J Patrick, G Pauletta, M Paulini, C Paus, D Pellett, L Pescara, TJ Phillips, G Piacentino, KT Pitts, A Pompos, L Pondrom, G Pope, F Prokoshin, J Proudfoot, F Ptohos, O Pukhov, G Punzi, A Rakitine, F Ratnikov, D Reher, A Reichold, P Renton, A Ribon, W Riegler, F Rimondi, L Ristori, M Riveline, WJ Robertson, T Rodrigo, S Rolli, L Rosenson, R Roser, R Rossin, C Rott, A Roy, A Ruiz, A Safonov, R St. Denis, WK Sakumoto, D Saltzberg, C Sanchez, A Sansoni, L Santi, H Sato, P Savard, A Savoy-Navarro, P Schlabach, EE Schmidt, MP Schmidt, M Schmitt, L Scodellaro, A Scott, A Scribano, A Sedov, S Segler, S Seidel, Y Seiya, A Semenov, F Semeria, T Shah, MD Shapiro, PF Shepard, T Shibayama, M Shimojima, M Shochet, A Sidoti, J Siegrist, A Sill, P Sinervo, P Singh, AJ Slaughter, K Sliwa, C Smith, FD Snider, A Solodsky, J Spalding, T Speer, P Sphicas, F Spinella, M Spiropulu, L Spiegel, J Steele, A Stefanini, J Strologas, F Strumia, D Stuart, K Sumorok, T Suzuki, T Takano, R Takashima, K Takikawa, P Tamburello, M Tanaka, B Tannenbaum, M Tecchio, RJ Tesarek, PK Teng, K Terashi, S Tether, AS Thompson, E Thomson, R Thurman-Keup, P Tipton, S Tkaczyk, D Toback, K Tollefson, A Tollestrup, D Tonelli, H Toyoda, W Trischuk, JF de Troconiz, J Tseng, D Tsybychev, N Turini, F Ukegawa, T Vaiciulis, J Valls, S Vejcik, G Velev, G Veramendi, R Vidal, I Vila, R Vilar, I Volobouev, M von der Mey, D Vucinic, RG Wagner, RL Wagner, NB Wallace, Z Wan, C Wang, MJ Wang, SM Wang, B Ward, S Waschke, T Watanabe, D Waters, T Watts, R Webb, H Wenzel, WC Wester, AB Wicklund, E Wicklund, T Wilkes, HH Williams, P Wilson, BL Winer, D Winn, S Wolbers, D Wolinski, J Wolinski, S Wolinski, S Worm, X Wu, J Wyss, W Yao, GP Yeh, P Yeh, J Yoh, C Yosef, T Yoshida, I Yu, S Yu, Z Yu, A Zanetti, F Zetti

Search for Leptoquark Pairs Decaying into nu nu + jets in ppbar Collisions at sqrt(s) = 1.8 TeV

Physical Review Letters 88 (2002) 191801 7pp

Authors:

C Hays, P. M. Tuts, G. Landsberg, H. B. Prosper

Search for leptoquark pairs decaying into nunu+jets in pp collisions at square root[s] = 1.8 TeV.

Physical review letters 88:19 (2002) 191801

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, N Amos, EW Anderson, Y Arnoud, C Avila, MM Baarmand, VV Babintsev, L Babukhadia, TC Bacon, A Baden, 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, F Borcherding, K Bos, T Bose, A Brandt, R Breedon, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, M Buehler, V Buescher, VS Burtovoi, JM Butler, F Canelli, W Carvalho, D Casey, Z Casilum, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, DK Cho, S Choi, S Chopra, JH Christenson, M Chung, D Claes, AR Clark, L Coney, B Connolly, WE Cooper, D Coppage, S Crépé-Renaudin, MAC Cummings, D Cutts, GA Davis, K Davis, K De, SJ De Jong, K Del Signore, M Demarteau, R Demina, P Demine, D Denisov, SP Denisov, S Desai, HT Diehl, M Diesburg, S Doulas, Y Ducros, LV Dudko, S Duensing, 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 Fahland, S Feher, D Fein, T Ferbel, F Filthaut, HE Fisk, Y Fisyak, E Flattum, F Fleuret, M Fortner, H Fox, KC Frame, S Fu, S Fuess, E Gallas, AN Galyaev, M Gao, V Gavrilov, RJ Genik, K Genser, CE Gerber, Y Gershtein, R Gilmartin, G Ginther, B Gómez, G Gómez, PI Goncharov, JL González Solís, H Gordon, LT Goss, K Gounder, A Goussiou, N Graf, G Graham, PD Grannis, JA Green, H Greenlee, ZD Greenwood, S Grinstein, L Groer, S Grünendahl, A Gupta, SN Gurzhiev, G Gutierrez, P Gutierrez, NJ Hadley, H Haggerty, S Hagopian, V Hagopian, RE Hall, P Hanlet, S Hansen, JM Hauptman, C Hays, C Hebert, D Hedin, JM Heinmiller, AP Heinson, U Heintz, MD Hildreth, R Hirosky, JD Hobbs, B Hoeneisen, 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, A Khanov, A Kharchilava, SK Kim, B Klima, B Knuteson, W Ko, JM Kohli, AV Kostritskiy, J Kotcher, B Kothari, AV Kotwal, 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, C Leggett, F Lehner, C Leonidopoulos, J Li, QZ Li, X 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, KM Mauritz, AA Mayorov, R McCarthy, T McMahon, HL Melanson, M Merkin, KW Merritt, C Miao, H Miettinen, D Mihalcea, CS Mishra, N Mokhov, NK Mondal, HE Montgomery, RW Moore, M Mostafa, H Da Motta, E Nagy, F Nang, M Narain, VS Narasimham, NA Naumann, HA Neal, JP Negret, S Negroni, T Nunnemann, D O'Neil, V Oguri, B Olivier, N Oshima, P Padley, LJ Pan, K Papageorgiou, A Para, N Parashar, R Partridge, N Parua, M Paterno, A Patwa, B Pawlik, J Perkins, O Peters, P Pétroff, R Piegaia, BG Pope, E Popkov, HB Prosper, S Protopopescu, MB Przybycien, J Qian, R Raja, S Rajagopalan, E Ramberg, PA Rapidis, NW Reay, S Reucroft, M Ridel, M Rijssenbeek, F Rizatdinova, T Rockwell, M Roco, C Royon, P Rubinov, R Ruchti, J Rutherfoord, BM Sabirov, G Sajot, A Santoro, L Sawyer, RD Schamberger, H Schellman, A Schwartzman, N Sen, E Shabalina, RK Shivpuri, D Shpakov, M Shupe, RA Sidwell, V Simak, H Singh, JB Singh, V Sirotenko, P Slattery, E Smith, RP Smith, R Snihur, GR Snow, J Snow, S Snyder, J Solomon, Y Song, V Sorín, M Sosebee, N Sotnikova, K Soustruznik, M Souza, NR Stanton, G Steinbrück, RW Stephens, F Stichelbaut, 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, SM Tripathi, TG Trippe, AS Turcot, PM Tuts, V Vaniev, R Van Kooten, N Varelas, LS Vertogradov, F Villeneuve-Seguier, AA Volkov, AP Vorobiev, HD Wahl, H Wang, Z-M Wang, J Warchol, G Watts, M Wayne, H Weerts, A White, JT White, D Whiteson, DA Wijngaarden, S Willis, SJ Wimpenny, J Womersley, DR Wood, Q Xu, R Yamada, P Yamin, T Yasuda, YA Yatsunenko, K Yip, S Youssef, J Yu, Z Yu, M Zanabria, X Zhang, H Zheng, B Zhou, Z Zhou, M Zielinski, D Zieminska, A Zieminski, V Zutshi, EG Zverev, A Zylberstejn, D0 Collaboration

Abstract:

We present the results of a search for leptoquark (LQ) pairs in (85.2+/-3.7) pb(-1) of pp* collider data collected by the D0 experiment at the Fermilab Tevatron. We observe no evidence for leptoquark production and set a limit on sigma(pp*-->LQLQ-->nunu+jets) as a function of the mass of the leptoquark (m(LQ)). Assuming the decay LQ-->nuq, we exclude scalar leptoquarks for m(LQ) < 98 GeV/c(2), and vector leptoquarks for m(LQ) < 200 GeV/c(2) and coupling which produces the minimum cross section, at a 95% confidence level.

Search for the scalar top quark in p p̄ collisions at √s = 1.8 TeV

Physical Review Letters 88:17 (2002) 1718021-1718026

Authors:

VM Abazov, B Abbott, A Abdesselam, M Abolins, V Abramov, BS Acharya, DL Adams, M Adams, SN Ahmed, GD Alexeev, GA Alves, N Amos, EW Anderson, Y Arnoud, MM Baarmand, VV Babintsev, L Babukhadia, TC Bacon, A Baden, 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, S Blessing, A Boehnlein, NI Bojko, F Borcherding, K Bos, A Brandt, R Breedon, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, M Buehler, V Buescher, VS Burtovoi, JM Butler, F Canelli, W Carvalho, D Casey, Z Casilum, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, DK Cho, S Choi, S Chopra, JH Christenson, M Chung, D Claes, AR Clark, J Cochran, L Coney, B Connolly, WE Cooper, D Coppage, S Crépé-Renaudin, MAC Cummings, D Cutts, GA Davis, K Davis, K De, SJ de Jong, K Del Signore, M Demarteau, R Demina, P Demine, D Denisov, SP Denisov, S Desai, HT Diehl, M Diesburg, S Doulas, Y Ducros, LV Dudko, S Duensing, L Duflot, SR Dugad

Abstract:

A search for scalar top (stop) quark pair production in the inclusive electron-muon-missing transverse energy final state was presented. The search was performed within the framework of the minimal supersymmetric standard model (MSSM) assuming the sneutrino to be the lightest supersymmetric particle. No evidence for signal was found for the dominant decays of the lightest stop. The cross-section limits of the stop, chargino and sneutrino masses were also derived.

Search for the scalar top quark in pp collisions at square root[s] = 1.8 TeV.

Phys Rev Lett 88:17 (2002) 171802

Authors:

VM Abazov, B Abbott, A Abdesselam, M Abolins, V Abramov, BS Acharya, DL Adams, M Adams, SN Ahmed, GD Alexeev, GA Alves, N Amos, EW Anderson, Y Arnoud, MM Baarmand, VV Babintsev, L Babukhadia, TC Bacon, A Baden, 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, S Blessing, A Boehnlein, NI Bojko, F Borcherding, K Bos, A Brandt, R Breedon, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, M Buehler, V Buescher, VS Burtovoi, JM Butler, F Canelli, W Carvalho, D Casey, Z Casilum, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, DK Cho, S Choi, S Chopra, JH Christenson, M Chung, D Claes, AR Clark, J Cochran, L Coney, B Connolly, WE Cooper, D Coppage, S Crépé-Renaudin, MAC Cummings, D Cutts, GA Davis, K Davis, K De, SJ De Jong, K Del Signore, M Demarteau, R Demina, P Demine, D Denisov, SP Denisov, S Desai, HT Diehl, M Diesburg, S Doulas, Y Ducros, LV Dudko, S Duensing, L Duflot, SR Dugad, A Duperrin, A Dyshkant, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, J Estrada, H Evans, VN Evdokimov, T Fahland, S Feher, D Fein, T Ferbel, F Filthaut, HE Fisk, Y Fisyak, E Flattum, F Fleuret, M Fortner, H Fox, KC Frame, S Fu, S Fuess, E Gallas, AN Galyaev, M Gao, V Gavrilov, RJ Genik, K Genser, CE Gerber, Y Gershtein, R Gilmartin, G Ginther, B Gómez, G Gómez, PI Goncharov, JL González Solís, H Gordon, LT Goss, K Gounder, A Goussiou, N Graf, G Graham, PD Grannis, JA Green, H Greenlee, ZD Greenwood, S Grinstein, L Groer, S Grünendahl, A Gupta, SN Gurzhiev, G Gutierrez, P Gutierrez, NJ Hadley, H Haggerty, S Hagopian, V Hagopian, RE Hall, P Hanlet, S Hansen, JM Hauptman, C Hays, C Hebert, D Hedin, JM Heinmiller, AP Heinson, U Heintz, T Heuring, MD Hildreth, R Hirosky, JD Hobbs, B Hoeneisen, Y Huang, R Illingworth, AS Ito, M Jaffré, S Jain, R Jesik, K Johns, M Johnson, A Jonckheere, M Jones, H Jöstlein, A Juste, W Kahl, S Kahn, E Kajfasz, AM Kalinin, D Karmanov, D Karmgard, Z Ke, R Kehoe, A Khanov, A Kharchilava, SK Kim, B Klima, B Knuteson, W Ko, JM Kohli, AV Kostritskiy, J Kotcher, B Kothari, AV Kotwal, 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, C Leggett, F Lehner, J Li, QZ Li, X 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, KM Mauritz, B May, AA Mayorov, R McCarthy, T McMahon, HL Melanson, M Merkin, KW Merritt, C Miao, H Miettinen, D Mihalcea, CS Mishra, N Mokhov, NK Mondal, HE Montgomery, RW Moore, M Mostafa, H Da Motta, E Nagy, F Nang, M Narain, VS Narasimham, HA Neal, JP Negret, S Negroni, A Nomerotski, T Nunnemann, D O'Neil, V Oguri, B Olivier, N Oshima, P Padley, LJ Pan, K Papageorgiou, A Para, N Parashar, R Partridge, N Parua, M Paterno, A Patwa, B Pawlik, J Perkins, M Peters, O Peters, P Pétroff, R Piegaia, BG Pope, E Popkov, HB Prosper, S Protopopescu, J Qian, R Raja, S Rajagopalan, E Ramberg, PA Rapidis, NW Reay, S Reucroft, M Ridel, M Rijssenbeek, F Rizatdinova, T Rockwell, M Roco, C Royon, P Rubinov, R Ruchti, J Rutherfoord, BM Sabirov, G Sajot, A Santoro, L Sawyer, RD Schamberger, H Schellman, A Schwartzman, N Sen, E Shabalina, RK Shivpuri, D Shpakov, M Shupe, RA Sidwell, V Simak, H Singh, JB Singh, V Sirotenko, P Slattery, E Smith, RP Smith, R Snihur, GR Snow, J Snow, S Snyder, J Solomon, V Sorín, M Sosebee, N Sotnikova, K Soustruznik, M Souza, NR Stanton, G Steinbrück, RW Stephens, F Stichelbaut, D Stoker, V Stolin, A Stone, DA Stoyanova, M Strauss, M Strovink, L Stutte, A Sznajder, M Talby, W Taylor, S Tentindo-Repond, SM Tripathi, TG Trippe, AS Turcot, PM Tuts, V Vaniev, R Van Kooten, N Varelas, LS Vertogradov, F Villeneuve-Seguier, AA Volkov, AP Vorobiev, HD Wahl, H Wang, Z-M Wang, J Warchol, G Watts, M Wayne, H Weerts, A White, JT White, D Whiteson, JA Wightman, DA Wijngaarden, S Willis, SJ Wimpenny, J Womersley, DR Wood, Q Xu, R Yamada, P Yamin, T Yasuda, YA Yatsunenko, K Yip, S Youssef, J Yu, Z Yu, M Zanabria, X Zhang, H Zheng, B Zhou, Z Zhou, M Zielinski, D Zieminska, A Zieminski, V Zutshi, EG Zverev, A Zylberstejn, D0 Collaboration

Abstract:

We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of pp events corresponding to 108.3 pb(-1) of data collected with the D0 detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the sneutrino is the lightest supersymmetric particle. For the dominant decays of the lightest stop, t-->b chi+1 and t-->blnu, no evidence for signal is found. We derive cross-section limits as a function of stop ( t ), chargino ( chi+1), and sneutrino ( nu) masses.