54,035 research outputs found
1ST MEASUREMENT OF GAMMA(D(S)(+)-]MU+NU)/GAMMA(D(S)(+)-]PHI-PI+)
No full textComplete Author List:
ACOSTA D, ATHANAS M, MASEK G, PAAR H, BEAN A, GRONBERG J, KUTSCHKE R, MENARY S, MORRISON RJ, NAKANISHI S, NELSON HN, NELSON TK, RICHMAN JD, RYD A, TAJIMA H, SCHMIDT D, SPERKA D, WITHERELL MS, PROCARIO M, YANG S, BALEST R, CHO K, DAOUDI M, FORD WT, JOHNSON DR, LINGEL K, LOHNER M, RANKIN P, SMITH JG, ALEXANDER JP, BEBEK C, BERKELMAN K, BESSON D, BROWDER TE, CASSEL DG, CHO HA, COFFMAN DM, DRELL PS, EHRLICH R, GALIK RS, GARCIASCIVERES M, GEISER B, GITTELMAN B, GRAY SW, HARTILL DL, HELTSLEY BK, JONES CD, JONES SL, KANDASWAMY J, KATAYAMA N, KIM PC, KREINICK DL, LUDWIG GS, MASUI J, MEVISSEN J, MISTRY NB, NG CR, NORDBERG E, OGG M, PATTERSON JR, PETERSON D, RILEY D, SALMAN S, SAPPER M, WORDEN H, WURTHWEIN F, AVERY P, FREYBERGER A, RODRIGUEZ J, STEPHENS R, YELTON J, CINABRO D, HENDERSON S, KINOSHITA K, LIU T, SAULNIER M, SHEN F, WILSON R, YAMAMOTO H, ONG B, SELEN M, SADOFF AJ, AMMAR R, BALL S, BARINGER P, COPPAGE D, COPTY N, DAVIS R, HANCOCK N, KELLY M, KWAK N, LAM H, KUBOTA Y, LATTERY M, NELSON JK, PATTON S, PERTICONE D, POLING R, SAVINOV V, SCHRENK S, WANG R, ALAM MS, KIM IJ, NEMATI B, ONEILL JJ, SEVERINI H, SUN CR, ZOELLER MM, CRAWFORD G, DAUBENMIER CM, FULTON R, FUJINO D, GAN KK, HONSCHEID K, KAGAN H, KASS R, LEE J, MALCHOW R, MORROW F, SKOVPEN Y, SUNG M, WHITE C, WHITMORE J, WILSON P, BUTLER F, FU X, KALBFLEISCH G, LAMBRECHT M, ROSS WR, SKUBIC P, SNOW J, WANG PL, WOOD M, BORTOLETTO D, BROWN DN, FAST J, MCILWAIN RL, MIAO T, MILLER DH, MODESITT M, SCHAFFNER SF, SHIBATA EI, SHIPSEY IPJ, WANG PN, BATTLE M, ERNST J, KROHA H, ROBERTS S, SPARKS K, THORNDIKE EH, WANG CH, DOMINICK J, SANGHERA S, SHELKOV V, SKWARNICKI T, STROYNOWSKI R, VOLOBOUEV I, ZADOROZHNY P, ARTUSO M, HE D, GOLDBERG M, HORWITZ N, KENNETT R, MONETI GC, MUHEIM F, MUKHIN Y, PLAYFER S, ROZEN Y, STONE S, THULASIDAS M, VASSEUR G, ZHU G, BARTELT J, CSORNA SE, EGYED Z, JAIN V, SHELDON P, AKERIB DS, BARISH B, CHADHA M, CHAN S, COWEN DF, EIGEN G, MILLER JS, OGRADY C, URHEIM J, WEINSTEIN A
Maximum-torque-per-ampere control of phase advance modulation of an SPM wind generator
No full textSurface permanent-magnet (SPM) machines are normally operated by controlling the d- and q-axis currents. This paper examines the control of SPM generators based on controlling the terminal voltage magnitude V and power-factor angle 8. This is well suited for generator operation when using a switched-mode rectifier and avoids the need for a rotor position sensor. The parameters required for generating a given value of torque with minimum phase current in order to minimize copper losses are derived in this paper. This will be achieved by controlling V and 8 to keep the d-axis current equal to zero at low speed, before switching to field-weakening control at higher speeds. Simulated and experimental results will be used to verify the control strategy and the efficiency achieved.Mehanathan Pathmanathan, Wen L. Soong and Nesimi Ertugru
Maximum torque per ampere control of phase advance modulation of a SPM wind generator
No full textSurface permanent magnet (PM) machines are normally operated by controlling the d-axis and q-axis currents. This paper examines the control of surface PM generators based on controlling the terminal voltage magnitude V and power-factor angle θ. This is well-suited for generator operation when using a switched-mode rectifier and avoids the need for a rotor position sensor. The parameters required for generating a given value of torque with minimum phase current in order to minimize copper losses are derived in this paper. This will be achieved by controlling V and θ to keep the d-axis current equal to zero at low speed, before switching to field-weakening control at higher speeds. Simulated and experimental results will be used to verify the control strategy, and the efficiency achieved.Mehanathan Pathmanathan, Wen Soong and Nesimi Ertugru
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Exclusive and inclusive semileptonic decays of B mesons to D mesons
No full textcomplete author list: Fulton R.; Jensen T.; Johnson D.; Kagan H.; Kass R.; Morrow F.; Whitmore J.; Wilson P.; Bortoletto D.; Chen W.; Dominick J.; McIlwain R.; Miller D.; Ng C.; Schaffner S.; Shibata E.; Shipsey I.; Yao W.; Battle M.; Sparks K.; Thorndike E.; Wang C.; Alam M.; Kim I.; Li W.; Romero V.; Sun C.; Wang P.; Zoeller M.; Goldberg M.; Haupt T.; Horwitz N.; Jain V.; Mestayer M.; Moneti G.; Rozen Y.; Rubin P.; Sharma V.; Skwarnicki T.; Thulasidas M.; Zhu G.; Csorna S.; Letson T.; Alexander J.; Artuso M.; Bebek C.; Berkelman K.; Browder T.; Cassel D.; Cheu E.; Coffman D.; Crawford G.; Dewire J.; Drell P.; Ehrlich R.; Galik R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Halling A.; Hartill D.; Heltsley B.; Honscheid K.; Kandaswamy J.; Katayama N.; Kreinick D.; Lewis J.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Nandi S.; Nordberg E.; O'Grady C.; Peterson D.; Pisharody M.; Riley D.; Sapper M.; Selen M.; Silverman A.; Stone S.; Worden H.; Worris M.; Sadoff A.; Avery P.; Besson D.; Garren L.; Yelton J.; Kinoshita K.; Pipkin F.; Procario M.; Wilson R.; Wolinski J.; Xiao D.; Zhu Y.; Ammar R.; Baringer P.; Coppage D.; Davis R.; Haas P.; Kwak N.; Lam H.; Ro S.; Kubota Y.; Nelson J.; Perticone D.; Poling R.; Fulton R.; Poling R.; Perticone D.; Nelson J.; Fulton R.</p
Erosie door open taludbekledingen. Samenvattend verslag + Bijlage A t/m D
No full textOpen taludbekledingen die bestaan uit in verband geplaatste betonblokken met gaten, bieden de mogelijkheid vegetatie te doen groeien, waardoor mogelijk een milieuvriendelijke oever kan worden verkregen. In het pioniersstadium van de vegetatie is het evenwel ongewenst dat de gatvulling uitspoelt. Teneinde de relatie tussen waterbeweging en erosie van de gatvulling vast te stellen, is door de Dienst Weg- en Waterbouwkunde van Rijkswaterstaat per brief d.d. 16 maart 1987 (kenmerk WB 570), opdracht verleend aan het Waterloopkundig Laboratorium tot het uitvoeren van onderzoek naar de erosie door open taludbekledingen. Het doel van het onderzoek is het ontwikkelen van ontwerprichtlijnen voor taludbekledingen met gaten die groter zijn dan de zand- of filterkorrels eronder. Hiertoe dient de kritieke waterbeweging bij een oever- of dijkbekleding te worden vastgesteld, waarbij nog toelaatbare erosie is te verwachten. De toelaatbare erosie mag daarbij maximaal gelijk zijn aan de hoeveelheid sediment in de gaten. Filter- of basismateriaal gelegen onder de elementen mag dus niet uitspoelen. Bij oeverbekledingen waar vegetatie een rol moet gaan spelen, is de toelaatbare erosie kleiner, dat wil zeggen in de gaten dient sediment achter te blijven.Steenzettingen - TAW/EN
Measurement of the B̄→D*lν̄ branching fractions and -Vcb-
No full textcomplete author list:
Barish B.; Chadha M.; Chan S.; Cowen D.; Eigen G.; Miller J.; O'Grady C.; Urheim J.; Weinstein A.; Acosta D.; Athanas M.; Masek G.; Paar H.; Gronberg J.; Kutschke R.; Menary S.; Morrison R.; Nakanishi S.; Nelson H.; Nelson T.; Qiao C.; Richman J.; Ryd A.; Tajima H.; Sperka D.; Witherell M.; Procario M.; Balest R.; Cho K.; Daoudi M.; Ford W.; Johnson D.; Lingel K.; Lohner M.; Rankin P.; Smith J.; Alexander J.; Bebek C.; Berkelman K.; Bloom K.; Browder T.; Cassel D.; Cho H.; Coffman D.; Crowcroft D.; Drell P.; Ehrlich R.; Gaidarev P.; Galik R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Hartill D.; Heltsley B.; Jones C.; Jones S.; Kandaswamy J.; Katayama N.; Kim P.; Kreinick D.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Ng C.; Nordberg E.; Patterson J.; Peterson D.; Riley D.; Salman S.; Sapper M.; Würthwein F.; Avery P.; Freyberger A.; Rodriguez J.; Yang S.; Yelton J.; Cinabro D.; Henderson S.; Liu T.; Saulnier M.; Wilson R.; Yamamoto H.; Bergfeld T.; Eisenstein B.; Gollin G.; Ong B.; Palmer M.; Selen M.; Thaler J.; Edwards K.; Ogg M.; Bellerive A.; Britton D.; Hyatt E.; MacFarlane D.; Patel P.; Spaan B.; Sadoff A.; Ammar R.; Ball S.; Baringer P.; Bean A.; Besson D.; Coppage D.; Copty N.; Davis R.; Hancock N.; Kelly M.; Kotov S.; Kravchenko I.; Kwak N.; Lam H.; Kubota Y.; Lattery M.; Momayezi M.; Nelson J.; Patton S.; Perticone D.; Poling R.; Savinov V.; Schrenk S.; Wang R.; Alam M.; Kim I.; Nemati B.; Ling Z.; O'Neill J.; Severini H.; Sun C.; Wappler F.; Crawford G.; Daubenmier C.; Fulton R.; Fujino D.; Gan K.; Honscheid K.; Kagan H.; Kass R.; Lee J.; Malchow R.; Skovpen Y.; Sung M.; White C.; Zoeller M.; Butler F.; Fu X.; Kalbfleisch G.; Ross W.; Skubic P.; Wood M.; Fast J.; Mcilwain R.; Miao T.; Miller D.; Modesitt M.; Payne D.; Shibata E.; Shipsey I.; Wang P.; Battle M.; Ernst J.; Gibbons L.; Kwon Y.; Roberts S.; Thorndike E.; Wang C.; Dominick J.; Lambrecht M.; Sanghera S.; Shelkov V.; Skwarnicki T.; Stroynowski R.; Volobouev I.; Wei G.; Zadorozhny P.; Artuso M.; Goldberg M.; He D.; Horwitz N.; Kennett R.; Mountain R.; Moneti G.; Muheim F.; Mukhin Y.; Playfer S.; Rozen Y.; Stone S.; Thulasidas M.; Vasseur G.; Xing X.; Zhu G.; Bartelt J.; Csorna S.; Egyed Z.; Jain V.; Gibaut D.; Kinoshita K.; Kinoshita K.; Barish B
Measurement of the D+/- production asymmetry in 7 TeV pp collisions
No full textThe asymmetry in the production cross-section \sigma of D+/- mesons, A_P = (\sigma(D+) - \sigma(D-))/(\sigma(D+) + \sigma(D-)), is measured in bins of pseudorapidity \eta and transverse momentum p_T within the acceptance of the LHCb detector. The result is obtained with a sample of D+ -> K_S pi+ decays corresponding to an integrated luminosity of 1.0 fb^-1, collected in pp collisions at a centre of mass energy of 7 TeV at the Large Hadron Collider. When integrated over the kinematic range 2.0 K_S pi+ decay is negligible. No significant dependence on \eta or p_T is observed
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Assessing late-time singular behaviour in symmetry-plane models of 3D Euler flow
No full textMotivated by work on stagnation-point type exact solutions of the 3D Euler fluid equations by Gibbon [Gibbon et. al. Phys. D, 132, 497, (1999)] and the subsequent demonstration of finite-time blowup by Constantin [Constantin, Math. Res. Notices, 9, 455, (2000)] we introduce a one-parameter family of models of the 3D Euler equations on a 2D symmetry plane. These models provide a collection of blow-up scenarios which admit analytical solutions and are computationally inexpensive in comparison to the full 3D Euler equations. We take advantage of these features to examine the efficacy of novel methods which aid the assessment of finite-time blow-up in numerical simulations. The principal of these is the mapping to regular systems [Bustamante, Phys. D, 240, 1092, (2011)]; a bijective nonlinear mapping of time and the prognostic variables based on a Beale-Kato-Majda (BKM) type supremum norm regularity condition [Beale et. al. Commun. Math. Phys. 94, 61, (1984)]. We show a 3 order of magnitude increase of accuracy of the singularity time when employing the mapping with negligible additional computational expense. An investigation of the spectra of the primary field (vortex stretching rate) allows us to confirm a power law decrement of the analyticity-strip width with time in agreement with rigorous bounds bridging between the global spatial behaviour and BKM theorems [Bustamante & Brachet, Phys. Rev. E. 86, (2012)]
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