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Measurement of W-pair cross sections in e+e- interactions at √s = 172 GeV and W-decay branching fractions

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 407:3-4 (1997) 419-431

Authors:

M Acciarri, O Adriani, M Aguilar-Benitez, S Ahlen, J Alcaraz, G Alemanni, J Allaby, A Aloisio, G Alverson, MG Alviggi, G Ambrosi, H Anderhub, VP Andreev, T Angelescu, F Anselmo, A Arefiev, T Azemoon, T Aziz, P Bagnaia, L Baksay, S Banerjee, K Banicz, A Barczyk, R Barilère, L Barone, P Bartalini, A Baschirotto, M Basile, R Battiston, A Bay, F Becattini, U Becker, F Behner, J Berdugo, P Berges, B Bertucci, BL Betev, S Bhattacharya, M Biasini, A Biland, GM Bilei, JJ Blaising, SC Blyth, GJ Bobbink, R Bock, A Böhm, L Boldizsar, B Borgia, D Bourilkov, M Bourquin, S Braccini, JG Branson, V Brigljevic, IC Brock, A Buffini, A Buijs, JD Burger, WJ Burger, J Busenitz, A Button, XD Cai, M Campanelli, M Capell, G Cara Romeo, G Carlino, AM Cartacci, J Casaus, G Castellini, F Cavallari, N Cavallo, C Cecchi, M Cerrada, F Cesaroni, M Chamizo, YH Chang, UK Chaturvedi, SV Chekanov, M Chemarin, A Chen, G Chen, HF Chen, HS Chen, X Chereau, G Chiefari, CY Chien, L Cifarelli, F Cindolo, C Civinini, I Clare, R Clare, HO Cohn, G Coignet, AP Colijn, N Colino, V Commichau, S Costantini, F Cotorobai, B de la Cruz

Abstract:

We report on the measurement of W-boson pair-production with the L3 detector at LEP at an average centre-of-mass energy of 172.13 GeV. In a data sample corresponding to a total luminosity of 10.25 pb-1 we select 110 four-fermion events with pairs of hadronic jets or leptons with high invariant masses. Branching fractions of W decays into different fermion-antifermion pairs are determined with and without the assumption of charged-current lepton universality. The branching fraction for hadronic W decays is measured to be: S(W → hadrons) = 64.2+3.7-3.8 (stat.) ± 0.5 (syst.) %. Combining all final states the total cross section for W-pair production is measured to be: σww = 12.27+1.41-1.32 (stat.) ± 0.23 (syst.) pb. The results are in good agreement with the Standard Model. © 1997 Elsevier Science B.V.
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Observation of diffractive W-boson production at the fermilab tevatron

Physical Review Letters 78:14 (1997) 2698-2703

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 report the first observation of diffractively produced W bosons.In a sample of W → eν events produced in pp collisions at √s=1.8TeV, we find an excess of events with a forward rapidity gap, which is attributed to diffraction.The probability that this excess is consistent with nondiffractive production is 1.1×10−4 (3.8σ).The relatively low fraction of W+ jet events observed within this excess implies that mainly quarks from the Pomeron, which mediates diffraction, participate in W production.The diffractive to nondiffractive W production ratio is found to be RW=(1.15±0.55)%.© 1997 The American Physical Society.
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Response of the ATLAS tile calorimeter prototype to muons

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 388:1-2 (1997) 64-78

Authors:

Z Ajaltouni, F Albiol, A Alifanov, P Amaral, A Amorim, K Anderson, C Angelini, A Astvatsaturov, D Autiero, F Badaud, G Barreira, S Berglund, G Blanchot, E Blucher, C Blaj, A Bogush, C Bohm, V Boldea, O Borisov, M Bosman, N Bouhemaid, P Brette, C Bromberg, M Brossard, J Budagov, L Caloba, J Carvalho, P Casado, M Cavalli-Sforza, V Cavasinni, R Chadelas, JC Chevaleyre, I Chirikov-Zorin, G Chlachidze, M Cobal, F Cogswell, F Colaço, S Constantinescu, D Costanzo, M Crouau, F Daudon, M David, T Davidek, J Dawson, JJ Dugne, K De, T Del Prete, A de Santo, B di Girolamo, S Dita, J Dolejsi, Z Dolezal, R Downing, I Efthymiopoulos, D Errede, S Errede, H Evans, A Ferrer, V Flaminio, E Gallas, M Gaspar, O Gildemeister, V Glagolev, V Golubev, A Gomes, V Grabsky, M Haney, H Hakopian, S Hellman, A Henriques, S Holmgren, PF Honoré, J Huston, Y Ivanyushenkov, E Johansson, K Jon-And, A Juste, S Kakurin, G Karapetian, A Karyukhin, Y Khokhlov, V Klyukhin, V Kolomoets, S Kopikov, M Kostrikov, V Kovtun, V Kukhtin, M Kulagin, V Lapin, C Lazzeroni, A Lebedev, R Leitner, J Li, I Liba, Y Lomakin, O Lomakina, M Lokajicek, A Maio, S Malyukov, F Marroquin

Abstract:

A study of high energy muons traversing the ATLAS hadron Tile calorimeter in the barrel region in the energy range between 10 and 300 GeV is presented. Both test beam experimental data and Monte Carlo simulations are given and show good agreement. The Tile calorimeter capability of detecting isolated muons over the above energy range is demonstrated. A signal to background ratio of about 10 is expected for the nominal LHC luminosity (1034 1/cm2s). The photoelectron statistics effect in the muon shape response is shown. The e/mip ratio is found to be 0.81 ± 0.03; the e/μ ratio is in the range 0.91-0.97. The energy loss of a muon in the calorimeter, dominated by the energy lost in the absorber, can be correlated to the energy loss in the active material. This correlation allows one to correct on an event by event basis the muon energy loss in the calorimeter and therefore reduce the low energy tails in the muon momentum distribution.
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Results from a combined test of an electromagnetic liquid argon calorimeter with a hadronic scintillating-tile calorimeter

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 387:3 (1997) 333-351

Authors:

Z Ajaltouni, F Albiol, A Alifanov, P Amaral, G Ambrosini, A Amorim, K Anderson, A Astvatsaturov, B Aubert, E Augé, D Autiero, G Azuelos, F Badaud, L Baisin, G Battistoni, A Bazan, C Bee, G Bellettini, S Berglund, JC Berset, C Blaj, G Blanchot, E Blucher, A Bogush, C Bohm, V Boldea, O Borisov, M Bosnian, N Bouhemaid, P Brette, C Bromberg, M Brossard, J Budagov, S Buono, L Caloba, DV Camin, B Canton, P Casado, D Cavalli, M Cavalli-Sforza, V Cavasinni, R Chadelas, R Chase, A Chekhtman, JC Chevaleyre, JL Chevalley, I Chirikov-Zorin, G Chlachidze, JC Chollet, M Cobal, F Cogswell, J Colas, J Collot, S Cologna, S Constantinescu, G Costa, D Costanzo, L Cozzi, M Crouau, P Dargent, F Daudon, M David, T Davidek, J Dawson, K De, C de la Taille, T Del Prete, P Depommier, P de Saintignon, A de Santo, B Dinkespiller, B di Girolamo, S Dita, J Dolejsi, Z Dolezal, R Downing, JJ Dugne, PY Duval, D Dzahini, I Efthymiopoulos, D Errede, S Errede, F Etienne, H Evans, P Fassnacht, N Fedyakin, A Ferrari, P Fcrreira, A Ferrer, V Flaminio, D Fouchez, D Fournier, G Fumagalli, E Gallas, M Gaspar, F Gianotti, O Gildemeister, DM Gingrich, V Glagolev, V Golubev

Abstract:

The first combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the barrel calorimeter of the future ATLAS experiment at the LHC. The energy resolution of pions in the energy range from 20 to 300 GeV at an incident angle θ of about 11c is well-described by the expression σ/E = ((46.5 ± 6.0)%/√E + (1.2 ± 0.3)%) ⊗ (3.2 ± 0.4)GeV/E. Shower profiles, shower leakage, and the angular resolution of hadronic showers were also studied.
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Measurement of bb̄ production correlations, B0B̄0 mixing, and a limit on ∈B in pp̄ collisions at √s=1.8 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 55:5 (1997) 2547-2558

Authors:

F Abe, H Akimoto, A Akopian, MG Albrow, SR Amendolia, D Amidei, J Antos, C Anway-Wiese, 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, 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 measurements of correlated bb̄ cross sections, μ-μ, correlations, the average B0B̄0 mixing parameter χ̄, and a limit on the CP-violating parameter ∈B. For these measurements, we use muon pairs from bb double semileptonic decays. The data used in this analysis were taken with the Collider_Detector at Fermilab and represent an integrated luminosity of 17.4±0.6 pb-1. The results concerning bb̄ production correlations are compared to predictions of next-to-leading order QCD computations.