Observation of events with an energetic forward neutron in deep inelastic scattering at HERA

PHYSICS LETTERS B 384:1-4 (1996) 388-400

Authors:

M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave, JR Okrasinski, J Repond, R Stanek, RL Talaga, H Zhang, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, GC Romeo, G Castellini, L Cifarelli, E Cindolo, A Contin, M Corradi, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, E Palmonari, A Polini, G Sartorelli, YZ Garcia, A Zichichi, C Amelung, A Bornheim, J Crittenden, R Deffner, T Doeker, M Eckert, L Feld, A Frey, M Geerts, M Grothe, H Hartmann, K Heinloth, L Heinz, E Hilger, HP Jakob, UF Katz, S Mengel, E Paul, M Pfeiffer, C Rembser, D Schramm, J Stamm, R Wedemeyer, S CampbellRobson, A Cassidy, WN Cottingham, N Dyce, B Foster, S George, ME Hayes, GP Heath, HF Heath, D Piccioni, DG Roff, RJ Tapper, R Yoshida, M Ameodo, R Ayad, M Capua, A Garfagnini, L Iannotti, M Schioppa, G Susinno, A Caldwell, N Cartiglia, Z Jing, W Liu, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, Q Zhu, P Borzemski, J Chwastowski, A Eskreys, Z Jakubowski, MB Przybycien, M Zachara, L Zawiejski, L Adamczyk, B Bednarek, K Jelen, D Kisielewska, T Kowalski, M Przybycien, E RulikowskaZarebska, L Suszycki, J Zajac, Z Dulinski, A Kotanski, G Abbiendi, LAT Bauerdick, U Behrens, H Beier, JK Bienlein, G Cases, O Deppe, K Desler, G Drews, M Flasinski, DJ Gilkinson, C Glasman, P Gottlicher, J GrosseKnetter, T Haas, W Hain, D Hasell, H Hessling, Y Iga, KF Johnson, P Joos, M Kasemann, R Klanner, W Koch, U Kotz, H Kowalski, J Labs, A Ladage, B Lohr, M Lowe, D Luke, J Mainusch, O Manczak, J Milewski, T Monteiro, JST Ng, D Notz, K Ohrenberg, K Piotrzkowski, M Roco, M Rohde, J Roldan, U Schneekloth, W Schulz, F Selonke, B Surrow, T Voss, D Westphal, G Wolf, U Wollmer, C Youngman, W Zeuner, HJ Grabosch, A Kharchilava, SM Mari, A Meyer, S Schlenstedt, N Wulff, G Barbagli, E Gallo, P Pelfer, G Maccarrone, S DePasquale, L Votano, A Bamberger, S Eisenhardt, T Trefzger, S Wolfle, JT Bromley, HN Brook, PJ Bussey, AT Doyle, DH Saxon, LE Sinclair, ML Utley, AS Wilson, A Dannemann, U Holm, D Horstmann, R Sinkus, K Wick, BD Burow, L Hagge, E Lohrmann, G Poelz, W Schott, F Zetsche, TC Bacon, N Brummer, I Butterworth, VL Harris, G Howell, BHY Hung, L Lamberti, KR Long, DB Miller, N Pavel, A Prinias, JK Sedgbeer, D Sideris, AF Whitfield, U Mallik, MZ Wang, SM Wang, JT Wu, P Cloth, D Filges, SH An, GH Cho, BJ Ko, SB Lee, SW Nam, HS Park, SK Park, S Kartik, HJ Kim, RR McNeil, W Metcalf, VK Nadendla, F Barreiro, JP Fernandez, R Graciani, JM Hernandez, L Hervas, L Labarga, M Martinez, J delPeso, J Puga, J Terron, JF deTroconiz, F Corriveau, DS Hanna, J Hartmann, LW Hung, JN Lim, CG Matthews, PM Patel, M Riveline, DG Stairs, M StLaurent, R Ullmann, G Zacek, V Bashkirov, BA Dolgoshein, A Stifutkin, GL Bashindzhagyan, PF Ermolov, LK Gladilin, YA Golubkov, VD Kobrin, IA Korzhavina, VA Kuzmin, O Yu, AS Proskuryakov, AA Savin, LM Shcheglova, AN Solomin, NP Zotov, M Botje, F Chlebana, J Engelen, M deKamps, P Kooijman, A Kruse, A vanSighem, H Tiecke, W Verkerke, J Vossebeld, M Vreeswijk, L Wiggers, E deWolf, R vanWoudenberg, D Acosta, B Bylsma, LS Durkin, J Gilmore, C Li, TY Ling, P Nylander, JH Park, TA Romankowski, DS Bailey, RJ Cashmore, AM CooperSarkar, RCE Devenish, N Harnew, M Lancaster, L Lindemann, JD McFall, C Nath, VA Noyes, A Quadt, JR Tickner, H Uijterwaal, R Walczak, DS Waters, FF Wilson, T Yip, A Bertolin, R Brugnera, R Carlin, F DalCorso, M DeGiorgi, U Dosselli, S Limentani, M Morandin, M Posocco, L Stanco, R Stroili, C Voci, F Zuin, J Bulmahn, RG Feild, BY Oh, JJ Whitmore, G DAgostini, G Marini, A Nigro, E Tassi, JC Hart, NA McCubbin, TP Shah, E Barberis, T Dubbs, C Heusch, M VanHook, W Lockman, JT Rahn, HFW Sadrozinski, A Seiden, DC Williams, J Biltzinger, RJ Seifert, O Schwarzer, AH Walenta, G Zech, H Abramowicz, G Briskin, S Dagan, A Levy, JI Fleck, M Inuzuka, T Ishii, M Kuze, S Mine, M Nakao, I Suzuki, K Tokushuku, K Umemori, S Yamada, Y Yamazaki, M Chiba, R Hamatsu, T Hirose, K Homma, S Kitamura, T Matsushita, K Yamuchi, R Cirio, M Costa, MI Ferrero, S Maselli, C Peroni, R Sacchi, A Solano, A Staiano, M Dardo, DC Bailey, F Benard, M Brkic, CP Fagerstroem, GF Hartner, KK Joo, GM Levman, JF Martin, RS Orr, S Polenz, CR Sampson, D Simmons, RJ Teuscher, JM Butterworth, CD Catterall, TW Jones, PB Kaziewicz, JB Lane, RL Saunders, J Shulman, MR Sutton, B Lu, LW Mo, W Bogusz, J Ciborowski, J Gajewski, G Grzelak, M Kasprzak, M Krzyzanowski, K Muchorowski, RJ Nowak, JM Pawlak, T Tymieniecka, AK Wroblewski, JA Zakrzewski, AF Zarnecki, C Coldewey, Y Eisenberg, D Hochman, U Karshon, D Revel, D ZerZion, WF Badgett, J Breiweg, D Chapin, RT Cross, S Dasu, C Foudas, RJ Loveless, S Mattingly, DD Reeder, S Silverstein, WH Smith, A Vaiciulis, M Wodarcyk, S Bhadra, ML Cardy, CP Fagerstroem, WR Frisken, KM Furutani, M Khakzad, WN Murray, WB Schmidke

W and Z boson production at HERA

AIP CONF PROC (1996) 198-208

A search for excited fermions in electron-proton collisions at HERA

Zeitschrift für Physik C Particles and Fields 65:4 (1995) 627-647

Authors:

M Derrick, D Krakauer, S Magill, B Musgrave, J Repond, J Schlereth, R Stanek, RL Talaga, J Thron, F Arzarello, R Ayad, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, GC Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, F Ciralli, A Contin, S D'Auria, F Frasconi, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Polini, G Sartorelli, R Timellini, YZ Garcia, A Zichichi, A Bargende, J Crittenden, K Desch, B Diekmann, T Doeker, M Eckart, L Feld, A Frey, M Geerts, G Geitz, M Grothe, H Hartmann, D Haun, K Heinloth, E Hilger, HP Jakob, UF Katz, SM Mari, A Mass, S Mengel, J Mollen, E Paul, C Rembser, R Schattevoy, JL Schneider, D Schramm, J Stamm, R Wedemeyer, S Campbell-Robson, A Cassidy, N Dyce, B Foster, S George, R Gilmore, GP Heath, HF Heath, TJ Llewellyn, CJS Morgado, DJP Norman, JA O'Mara, RJ Tapper, SS Wilson, R Yoshida, RR Rau, M Arneodo, L Iannotti, M Schioppa, G Susinno, A Bernstein, A Caldwell, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, P Borzemski, J Chwastowski

Abstract:

A search for excited states of the standard model fermions was performed using the ZEUS detector at the HERA electron-proton collider, operating at a centre of mass energy of 296 GeV. In a sample corresponding to an integrated luminosity of 0.55 pb-1, no evidence was found for any resonant state decaying into final states composed of a fermion and a gauge boson. Limits on the coupling strength times branching ratio of excited fermions are presented for masses between 50 GeV and 250 GeV, extending previous search regions significantly. © 1995 Springer-Verlag.

Laser ablation of polymeric materials at 157 nm

Journal of Applied Physics 77:6 (1995) 2343-2350

Authors:

A Costela, I García-Moreno, F Florido, JM Figuera, R Sastre, SM Hooker, JS Cashmore, CE Webb

Abstract:

Results are presented on the ablation by 157 nm laser radiation of polytetrafluoroethylene (PTFE), polyimide, polyhydroxybutyrate (PHB), poly(methyl methacrylate) (PMMA), and poly(2-hydroxyethyl methacrylate) with 1% of ethylene glycol dimethacrylate as a crosslinking monomer. Direct photoetching of PHB and undoped PTFE is demonstrated for laser fluences ranging from 0.05 to 0.8 J/cm2. The dependence of the ablation process on the polymer structure is analyzed, and insight into the ablation mechanism is gained from an analysis of the data using Beer-Lambert's law and the kinetic model of the moving interface. Consideration of the absorbed energy density required to initiate significant ablation suggests that the photoetching mechanism is similar for all the polymers studied. © 1995 American Institute of Physics.

Measurement of elastic ρ 0 photoproduction at HERA

Zeitschrift für Physik C: Particles and Fields 69:1 (1995) 39-54

Authors:

M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave, J Repond, R Stanek, RL Talaga, H Zhang, R Ayad, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, A Contin, M Corradi, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Polini, G Sartorelli, T Timellini, Y Zamora Garcia, A Zichichi, B Bargende, A Bornheim, J Crittenden, K Desch, B Diekmann, T Doeker, M Eckert, L Feld, A Frey, M Geerts, M Grothe, H Hartmann, K Heinloth, E Hilger, HP Jakob, UF Katz, S Mengel, J Mollen, E Paul, M Pfeiffer, C Rembser, D Schramm, J Stamm, R Wedemeyer, S Campbell-Robson, A Cassidy, N Dyce, B Foster, S George, R Gilmore, GP Heath, HF Heath, TJ Llewellyn, CJS Morgado, DJP Norman, JA O'Mara, RJ Tapper, SS Wilson, R Yoshida, RR Rau, M Arneodo, M Capua, A Garfagnini, L Iannotti, M Schioppa, G Susinno, A Bernstein, A Caldwell, N Cartiglia, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, Q Zhu, P Borzemski, J Chwastowski, A Eskreys, K Piotrzkowski, M Zachara

Abstract:

Elastic ρ 0 photoproduction has been measured using the ZEUS detector at HERA. Untagged photoproduction events from ep interactions were used to measure the reaction γp→ρ 0 p(ρ 0)→π +π-) at photon-proton centre-of-mass energies between 60 and 80 GeV and |t|<0.5 GeV2, where t is the square of the four-momentum transferred at the proton vertex. The differential cross section dσ/d M ππ where M ππ is the invariant mass of the two pions, and the integrated cross section, σγp→ρ{variant}0ρ{variant}, are presented; the latter was measured to be 14.7±0.4 (stat.) ±2.4 (syst.)μb. The differential cross section dσ/dt has an approximately exponential shape; a fit of the type A t ′ exp(-b t ′ |t|+c t ′ t 2) yields a t-slope b t ′ =9.9±1.2 (stat.) ±1.4 (syst.) GeV-2. The results, when compared to low energy data, show a weak energy dependence of both σγp→ρ{variant}0p and of the t-slope. The ρ 0 is produced predominantly with transverse polarisation, demostrating that s-channel helicity conservation holds at these energies. © 1996 Springer-Verlag.