Direct top-quark width measurement at CDF

• Published in: Physical review letters Vol. 105; no. 23; p. 232003
• Main Authors: Aaltonen, T, Álvarez González, B, Amerio, S, Amidei, D, Anastassov, A, Annovi, A, Antos, J, Apollinari, G, Appel, J A, Apresyan, A, Arisawa, T, Artikov, A, Asaadi, J, Ashmanskas, W, Auerbach, B, Aurisano, A, Azfar, F, Badgett, W, Barbaro-Galtieri, A, Barnes, V E, Barnett, B A, Barria, P, Bartos, P, Bauce, M, Bauer, G, Bedeschi, F, Beecher, D, Behari, S, Bellettini, G, Bellinger, J, Benjamin, D, Beretvas, A, Bhatti, A, Binkley, M, Bisello, D, Bizjak, I, Bland, K R, Blocker, C, Blumenfeld, B, Bocci, A, Bodek, A, Bortoletto, D, Boudreau, J, Boveia, A, Brau, B, Brigliadori, L, Brisuda, A, Bromberg, C, Brucken, E, Bucciantonio, M, Budagov, J, Budd, H S, Budd, S, Burkett, K, Busetto, G, Bussey, P, Buzatu, A, Cabrera, S, Calancha, C, Camarda, S, Campanelli, M, Campbell, M, Canelli, F, Canepa, A, Carls, B, Carlsmith, D, Carosi, R, Carrillo, S, Carron, S, Casal, B, Casarsa, M, Castro, A, Catastini, P, Cauz, D, Cavaliere, V, Cavalli-Sforza, M, Cerri, A, Cerrito, L, Chen, Y C, Chertok, M, Chiarelli, G, Chlachidze, G, Chlebana, F, Cho, K, Chokheli, D, Chou, J P, Chung, W H, Chung, Y S, Ciobanu, C I, Ciocci, M A, Clark, A, Clark, D, Compostella, G, Convery, M E, Conway, J, Corbo, M, Cordelli, M, Cox, C A, Cox, D J, Crescioli, F
• Format: Journal Article
• Language: English
• Published: United States 03-12-2010
• Subjects: ACCELERATORS; BARYON-BARYON INTERACTIONS; BOSONS; CALIBRATION; CYCLIC ACCELERATORS; DECAY; DIMENSIONS; ELEMENTARY PARTICLES; ENERGY RANGE; FERMILAB COLLIDER DETECTOR; FERMILAB TEVATRON; FERMIONS; FIELD THEORIES; GEV RANGE; GEV RANGE 01-10; GEV RANGE 100-1000; GRAND UNIFIED THEORY; HADRON-HADRON INTERACTIONS; INTERACTIONS; INTERMEDIATE BOSONS; INTERMEDIATE VECTOR BOSONS; JETS; LEPTONS; LUMINOSITY; MASS; MATHEMATICAL MODELS; MEASURING INSTRUMENTS; NUCLEON-NUCLEON INTERACTIONS; OPTICAL PROPERTIES; PARTICLE INTERACTIONS; PARTICLE MODELS; PHYSICAL PROPERTIES; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; POSTULATED PARTICLES; PROTON-NUCLEON INTERACTIONS; PROTON-PROTON INTERACTIONS; QUANTUM FIELD THEORY; QUARKS; RADIATION DETECTORS; STANDARD MODEL; SYNCHROTRONS; T QUARKS; TOP PARTICLES; UNIFIED GAUGE MODELS; W MINUS BOSONS; W PLUS BOSONS; WIDTH
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.105.232003

We present a measurement of the top-quark width in the lepton+jets decay channel of tt events produced in p p collisions at Fermilab's Tevatron collider and collected by the CDF II detector. From a data sample corresponding to 4.3 fb(-1) of integrated luminosity, we identify 756 candidate events. The top-quark mass and the mass of the hadronically decaying W boson that comes from the top-quark decay are reconstructed for each event and compared with templates of different top-quark widths (Γ(t)) and deviations from nominal jet energy scale (Δ(JES)) to perform a simultaneous fit for both parameters, where Δ(JES) is used for the in situ calibration of the jet energy scale. By applying a Feldman-Cousins approach, we establish an upper limit at 95% confidence level (CL) of Γ(t) <7.6 GeV and a two-sided 68% CL interval of 0.3 GeV <Γ(t) <4.4  GeV for a top-quark mass of 172.5 GeV/c(2), which are consistent with the standard model prediction.