ATLAS

Research group

Research theme

Sub department

About

Related research groups

A measurement of the energy loss spectrum of 150 GeV muons in iron

Zeitschrift Fur Physik C Particles and Fields 73:3 (1997) 455-463

Authors:

E Berger, R Blair, J Dawson, T Fuess, V Guarino, N Hill, S Magill, E May, L Nodulman, L Price, J Proudfoot, R Stanek, D Underwood, R Wagner, B Wicklund, G Blanchot, M Bosman, P Casado, M Cavalli-Sforza, I Efthymiopoulos, Y Ivanyushenkov, A Juste, L Miralles, S Orteu, C Padilla, JA Perlas, I Riu, B Ronceux, F Teubert, R Arsenescu, S Constantinescu, C Blaj, V Boldea, S Dita, M Cobal, O Gildemeister, M Nessi, A Henriques, L Poggioli, P Sonderegger, G Karapetian, K Anderson, E Blucher, H Evans, F Merritt, J Pilcher, H Sanders, M Shochet, F Tang, A Turcot, D Wagner, Z Ajaltouni, F Badaud, N Bouhemaid, P Brette, M Brassard, R Chadelas, JC Chevaleyre, M Crouau, F Daudon, JJ Dugne, B Michel, G Montarou, GS Muanza, D Pallin, H Plothow-Besch, S Poirot, G Reinmuth, LP Says, F Vazeille, A Astvatsaturov, O Borisov, J Budagov, I Chirikov-Zorin, G Chlachidze, V Glagolev, S Kakurin, V Kolomoets, V Kovtun, V Kukhtin, A Lebedev, I Liba, O Lomakina, Y Lomakin, S Malyukov, I Minashvili, D Pantea, O Pukhov, V Romanov, N Russakovich, V Senchishin, A Semenov, A Sissakian, A Shchelchkov, V Shevtsov, S Studenov, S Tokar, N Topilin, V Vinogradov, S Vorozhtsov

Abstract:

The energy loss spectrum of 150 GeV muons has been measured with a prototype of the ATLAS hadron calorimeter in the H8 beam of the CERN SPS. The differential probability dP/dυ per radiation length of a fractional energy loss υ = ΔEμ/Eμ has been measured in the range υ = 0.01 ÷ 0.95; it is compared with the theoretical predictions for energy losses due to bremsstrahlung and production of electron-positron pairs or of energetic knock-on electrons. The integrated probability ∫0.010.95(dP/dυ)dυ is (1.610 ± 0.015stat ±0 .105syst)·10-3 in agreement with the theoretical predictions 1.556·10-3 and 1.619·10-3. Agreement with theory is also found in two intervals of υ where production of electron-positron pairs and knock-on electrons dominates. In the region of bremsstrahlung dominance (υ = 0.12 ÷ 0.95) the measured integrated probability (1.160 ± 0.040stat ± 0.075syst)·10-4 is in agreement with the theoretical value of 1.185·10-4, obtained using the Petrukhin and Shestakov description of the bremsstrahlung process. The same result is about 3.6 standard deviations (defined as the quadratic sum of statistical and systematic errors) lower than the theoretical prediction of 1.472·10-4, obtained using Tsai's description of bremsstrahlung. © Springer-Verlag 1997.
More details from the publisher
More details

Direct measurement of the top quark mass

Physical Review Letters 79:7 (1997) 1197-1202

Authors:

S Abachi, B Abbott, M Abolins, BS Acharya, I Adam, DL Adams, M Adams, S Ahn, H Aihara, GA Alves, E Amidi, N Amos, EW Anderson, R Astur, MM Baarmand, A Baden, V Balamurali, J Balderston, B Baldin, S Banerjee, J Bantly, E Barberis, JF Bartlett, K Bazizi, A Belyaev, SB Beri, I Bertram, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, N Biswas, G Blazey, S Blessing, P Bloom, A Boehnlein, NI Bojko, F Borcherding, J Borders, C Boswell, A Brandt, R Brock, A Bross, D Buchholz, VS Burtovoi, JM Butler, W Carvalho, D Casey, H Castilla-Valdez, D Chakraborty, SM Chang, SV Chekulaev, LP Chen, W Chen, S Choi, S Chopra, BC Choudhary, JH Christenson, M Chung, D Claes, AR Clark, WG Cobau, J Cochran, WE Cooper, C Cretsinger, D Cullen-Vidal, MAC Cummings, D Cutts, OI Dahl, K Davis, K De, K Del Signore, M Demarteau, D Denisov, SP Denisov, HT Diehl, M Diesburg, G Di Loreto, P Draper, J Drinkard, Y Ducros, LV Dudko, SR Dugad, D Edmunds, J Ellison, VD Elvira, R Engelmann, S Eno, G Eppley, P Ermolov, OV Eroshin, VN Evdokimov, T Fahland, M Fatyga, MK Fatyga, J Featherly, S Feher, D Fein, T Ferbel, G Finocchiaro

Abstract:

We measure the top quark mass mt t¯t using pairs produced in the D0 detector by √s = 1.8 TeV p ¯p collisions in a 125pb-1 exposure at the Fermilab Tevatron. We make a two constraint fit to mt in t¯t → b W+ ¯bW- final states with one W decaying to q¯q and the other to ev or μ v. Events are binned in fit mass versus a measure of probability for events to be signal rather than background. Likelihood fits to the data yield mt = 17.3 ± 5.6 (stat) ± 6.2(syst) GeV/c2. © 1998 The American Physical Society.
More details from the publisher

Double parton scattering in [Formula presented] collisions at [Formula presented]

Physical Review D Particles Fields Gravitation and Cosmology 56:7 (1997) 3811-3832

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Asakawa, W Ashmanskas, M Atac, F Azfar, P Azzi-Bacchetta, N Bacchetta, W Badgett, S Bagdasarov, MW Bailey, J Bao, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, E Barzi, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Benlloch, J Bensinger, D Benton, A Beretvas, JP Berge, J Berryhill, S Bertolucci, B Bevensee, A Bhatti, K Biery, M Binkley, D Bisello, RE Blair, C Blocker, A Bodek, W Bokhari, V Bolognesi, G Bolla, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, J Cammerata, C Campagnari, M Campbell, A Caner, W Carithers, D Carlsmith, A Castro, D Cauz, Y Cen, F Cervelli, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, G Chiarelli, T Chikamatsu, CN Chiou, L Christofek, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, C Couyoumtzelis, D Crane, D Cronin-Hennessy, R Culbertson, T Daniels, F DeJongh, S Delchamps, S Dell'Agnello, M Dell'Orso, R Demina, L Demortier

Abstract:

A strong signal for double parton (DP) scattering is observed in a [Formula presented] sample of [Formula presented] data from the CDF experiment at the Fermilab Tevatron. In DP events, two separate hard scatterings take place in a single [Formula presented] collision. We isolate a large sample of data [Formula presented] of which 53% are found to be DP. The process-independent parameter of double parton scattering, [Formula presented] is obtained without reference to theoretical calculations by comparing observed DP events to events with hard scatterings in separate [Formula presented] collisions. The result [Formula presented] represents a significant improvement over previous measurements, and is used to constrain simple models of parton spatial density. The Feynman [Formula presented] dependence of [Formula presented] is investigated and none is apparent. Further, no evidence is found for kinematic correlations between the two scatterings in DP events. © 1997 The American Physical Society.
More details from the publisher
More details

First observation of the all-hadronic decay of tt― pairs

Physical Review Letters 79:11 (1997) 1992-1997

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Asakawa, W Ashmanskas, M Atac, F Azfar, P Azzi-Bacchetta, N Bacchetta, W Badgett, S Bagdasarov, MW Bailey, J Bao, P De Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, E Barzi, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Benlloch, J Bensinger, D Benton, A Beretvas, JP Berge, J Berryhill, S Bertolucci, B Bevensee, A Bhatti, K Biery, M Binkley, D Bisello, RE Blair, C Blocker, A Bodek, W Bokhari, V Bolognesi, G Bolla, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, J Cammerata, C Campagnari, M Campbell, A Caner, W Carithers, D Carlsmith, A Castro, D Cauz, Y Cen, F Cervelli, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, G Chiarelli, T Chikamatsu, CN Chiou, L Christofek, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, C Couyoumtzelis, D Crane, D Cronin-Hennessy, R Culbertson, T Daniels, F DeJongh, S Delchamps, S Dell’agnello, M Dell’orso, R Demina, L Demortier

Abstract:

We present the first observation of the all hadronic decay of tt― pairs. The analysis is performed using 109 pb−1 of pp― collisions at s = 1.8 TeV collected with the Collider Detector at Fermilab. We observe an excess of events with five or more jets, including one or two b jets, relative to background expectations. Based on this excess we evaluate the production cross section to be in agreement with previous results. We measure the top mass to be 186±10±12 GeV/c2. © 1997 The American Physical Society.
More details from the publisher
More details

Limits on quark-lepton compositeness scales from dileptons produced in 1.8 TeV pp-collisions

Physical Review Letters 79:12 (1997) 2198-2203

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, S Aota, G Apollinari, T Asakawa, W Ashmanskas, M Atac, F Azfar, P Azzi-Bacchetta, N Bacchetta, W Badgett, S Bagdasarov, MW Bailey, J Bao, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, E Barzi, G Bauer, T Baumann, F Bedeschi, S Behrends, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Benlloch, J Bensinger, D Benton, A Beretvas, JP Berge, J Berryhill, S Bertolucci, B Bevensee, A Bhatti, K Biery, M Binkley, D Bisello, RE Blair, C Blocker, A Bodek, W Bokhari, V Bolognesi, G Bolla, D Bortoletto, J Boudreau, L Breccia, C Bromberg, N Bruner, E Buckley-Geer, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, J Cammerata, C Campagnari, M Campbell, A Caner, W Carithers, D Carlsmith, A Castro, D Cauz, Y Cen, F Cervelli, PS Chang, PT Chang, HY Chao, J Chapman, MT Cheng, G Chiarelli, T Chikamatsu, CN Chiou, L Christofek, S Cihangir, AG Clark, M Cobal, E Cocca, M Contreras, J Conway, J Cooper, M Cordelli, C Couyoumtzelis, D Crane, D Cronin-Hennessy, R Culbertson, T Daniels, F DeJongh, S Delchamps, S Dell’agnello, M Dell’orso, R Demina, L Demortier

Abstract:

The dilepton mass spectrum in pp-→|+|-+X interactions is studied using dielectrons (ee) and dimuons (μμ) in 100 pb- of data collected with the Collider Detector at Fermilab. The data are consistent with standard model predictions. The mass spectrum, being a probe for new physics, is examined for new interactions of quarks and leptons from a common composite structure. Assuming a contact interaction with the conventional coupling g20/4π = 1, limits on chiral quark-electron and quark-muon compositeness scales in the range of 2.5 to 4.2 TeV are obtained. © 1997 The American Physical Society.
More details from the publisher
More details