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Measurements of the top-quark mass using charged particle tracking

Physical Review D - Particles, Fields, Gravitation and Cosmology 81:3 (2010)

Authors:

T Aaltonen, J Adelman, T Akimoto, BA González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Barria, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, S Burke, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, M Campanelli, M Campbell, F Canelli, A Canepa, B Carls, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, T Chwalek, CI Ciobanu, MA Ciocci, A Clark, D Clark

Abstract:

We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9fb-1 of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9-8.5+9.5(stat)±2. 9(syst)GeV/c2, and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5-8.9+8.8(stat)±3. 8(syst)GeV/c2. These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7±6.3(stat)±2. 6(syst)GeV/c2. © 2010 The American Physical Society.
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Black hole growth and host galaxy morphology

ArXiv 1002.1488 (2010)

Authors:

Kevin Schawinski, C Megan Urry, Shanil Virani, Paolo Coppi, Steven P Bamford, Ezequiel Treister, Chris J Lintott, Marc Sarzi, William C Keel, Sugata Kaviraj, Carolin N Cardamone, Karen L Masters, Nicholas P Ross, the Galaxy Zoo team

Abstract:

We use data from large surveys of the local Universe (SDSS+Galaxy Zoo) to show that the galaxy-black hole connection is linked to host morphology at a fundamental level. The fraction of early-type galaxies with actively growing black holes, and therefore the AGN duty cycle, declines significantly with increasing black hole mass. Late-type galaxies exhibit the opposite trend: the fraction of actively growing black holes increases with black hole mass.
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Fast infrared variability from a relativistic jet in GX 339-4

(2010)

Authors:

P Casella, TJ Maccarone, K O'Brien, RP Fender, DM Russell, M van der Klis, A Pe'er, D Maitra, D Altamirano, T Belloni, G Kanbach, M Klein-Wolt, E Mason, P Soleri, A Stefanescu, K Wiersema, R Wijnands
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The Commensal Real-time ASKAP Fast Transients (CRAFT) survey

(2010)

Authors:

Jean-Pierre Macquart, the CRAFT collaboration, :, M Bailes, NDR Bhat, GC Bower, JD Bunton, S Chatterjee, T Colegate, JM Cordes, L D'Addario, A Deller, R Dodson, R Fender, K Haines, P Hall, C Harris, A Hotan, S Johnston, DL Jones, M Keith, JY Koay, TJW Lazio, W Majid, T Murphy, R Navarro, C Phillips, P Quinn, RA Preston, B Stansby, I Stairs, B Stappers, L Staveley-Smith, S Tingay, D Thompson, W van Straten, K Wagstaff, M Warren, R Wayth, L Wen
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Galaxy Zoo: Dust in Spirals

ArXiv 1001.1744 (2010)

Authors:

Karen L Masters, Robert C Nichol, Steven Bamford, Moein Mosleh, Chris J Lintott, Dan Andreescu, Edward M Edmondson, William C Keel, Phil Murray, M Jordan Raddick, Kevin Schawinski, Anze Slosar, Alexander S Szalay, Daniel Thomas, Jan Vandenberg

Abstract:

We investigate the effect of dust on spiral galaxies by measuring the inclination-dependence of optical colours for 24,276 well-resolved SDSS galaxies visually classified in Galaxy Zoo. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4 magnitudes for the ugri passbands. We split the sample into "bulgy" (early-type) and "disky" (late-type) spirals using the SDSS fracdeV (or f_DeV) parameter and show that the average face-on colour of "bulgy" spirals is redder than the average edge-on colour of "disky" spirals. This shows that the observed optical colour of a spiral galaxy is determined almost equally by the spiral type (via the bulge-disk ratio and stellar populations), and reddening due to dust. We find that both luminosity and spiral type affect the total amount of extinction, with "disky" spirals at M_r ~ -21.5 mags having the most reddening. This decrease of reddening for the most luminous spirals has not been observed before and may be related to their lower levels of recent star formation. We compare our results with the latest dust attenuation models of Tuffs et al. We find that the model reproduces the observed trends reasonably well but overpredicts the amount of u-band attenuation in edge-on galaxies. We end by discussing the effects of dust on large galaxy surveys and emphasize that these effects will become important as we push to higher precision measurements of galaxy properties and their clustering.
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