共查询到20条相似文献,搜索用时 359 毫秒
1.
Araki T Eguchi K Enomoto S Furuno K Ichimura K Ikeda H Inoue K Ishihara K Iwamoto T Kawashima T Kishimoto Y Koga M Koseki Y Maeda T Mitsui T Motoki M Nakajima K Ogawa H Owada K Ricol JS Shimizu I Shirai J Suekane F Suzuki A Tada K Tajima O Tamae K Tsuda Y Watanabe H Busenitz J Classen T Djurcic Z Keefer G McKinny K Mei DM Piepke A Yakushev E Berger BE Chan YD Decowski MP Dwyer DA Freedman SJ Fu Y Fujikawa BK Goldman J Gray F Heeger KM Lesko KT Luk KB Murayama H Poon AW Steiner HM Winslow LA 《Physical review letters》2005,94(8):081801
We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 nu (e) candidate events with energies above 3.4 MeV compared to 365.2+/-23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8+/-7.3 expected background events, the statistical significance for reactor nu (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from nu (e) oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2). A global analysis of data from KamLAND and solar-neutrino experiments yields Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2) and tan((2)theta=0.40(+0.10)(-0.07), the most precise determination to date. 相似文献
2.
Ahmed SN Anthony AE Beier EW Bellerive A Biller SD Boger J Boulay MG Bowler MG Bowles TJ Brice SJ Bullard TV Chan YD Chen M Chen X Cleveland BT Cox GA Dai X Dalnoki-Veress F Doe PJ Dosanjh RS Doucas G Dragowsky MR Duba CA Duncan FA Dunford M Dunmore JA Earle ED Elliott SR Evans HC Ewan GT Farine J Fergani H Fleurot F Formaggio JA Fowler MM Frame K Fulsom BG Gagnon N Graham K Grant DR Hahn RL Hall JC Hallin AL Hallman ED Hamer AS Handler WB Hargrove CK Harvey PJ Hazama R Heeger KM Heintzelman WJ 《Physical review letters》2004,92(18):181301
The Sudbury Neutrino Observatory has precisely determined the total active (nu(x)) 8B solar neutrino flux without assumptions about the energy dependence of the nu(e) survival probability. The measurements were made with dissolved NaCl in heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27(stat)+/-0.38(syst) x 10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Deltam(2)=7.1(+1.2)(-0.6) x 10(-5) eV(2) and theta=32.5(+2.4)(-2.3) degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations. 相似文献
3.
Aharmim B Ahmed SN Amsbaugh JF Anthony AE Banar J Barros N Beier EW Bellerive A Beltran B Bergevin M Biller SD Boudjemline K Boulay MG Bowles TJ Browne MC Bullard TV Burritt TH Cai B Chan YD Chauhan D Chen M Cleveland BT Cox-Mobrand GA Currat CA Dai X Deng H Detwiler J DiMarco M Doe PJ Doucas G Drouin PL Duba CA Duncan FA Dunford M Earle ED Elliott SR Evans HC Ewan GT Farine J Fergani H Fleurot F Ford RJ Formaggio JA Fowler MM Gagnon N Germani JV Goldschmidt A Goon JT Graham K Guillian E 《Physical review letters》2008,101(11):111301
The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54_-0.31;+0.33(stat)-0.34+0.36(syst)x10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Deltam2=7.59_-0.21;+0.19x10(-5) eV2 and theta=34.4_-1.2;+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results. 相似文献
4.
Ahn MH Aoki S Ashie Y Bhang H Boyd S Casper D Choi JH Fukuda S Fukuda Y Gran R Hara T Hasegawa M Hasegawa T Hayashi K Hayato Y Hill J Ichikawa AK Ikeda A Inagaki T Ishida T Ishii T Ishitsuka M Itow Y Iwashita T Jang HI Jang JS Jeon EJ Joo KK Jung CK Kajita T Kameda J Kaneyuki K Kato I Kearns E Kibayashi A Kielczewska D Kim BJ Kim CO Kim JY Kim SB Kobayashi K Kobayashi T Koshio Y Kropp WR Learned JG Lim SH Lim IT Maesaka H Maruyama T Matsuno S Mauger C Mcgrew C Minamino A Mine S Miura M Miyano K 《Physical review letters》2004,93(5):051801
We present a search for electron neutrino appearance from accelerator-produced muon neutrinos in the K2K long-baseline neutrino experiment. One candidate event is found in the data corresponding to an exposure of 4.8 x 10(19) protons on target. The expected background in the absence of neutrino oscillations is estimated to be 2.4+/-0.6 events and is dominated by misidentification of events from neutral current pi(0) production. We exclude the nu(micro) to nu(e) oscillations at 90% C.L. for the effective mixing angle in the 2-flavor approximation of sin((2)2theta(microe)( approximately 1/2sin((2)2theta(13))>0.15 at Deltam(2)(microe)=2.8 x 10(-3) eV(2), the best-fit value of the nu(micro) disappearance analysis in K2K. The most stringent limit of sin((2)2theta(microe)<0.09 is obtained at Deltam(2)(microe)=6 x 10(-3) eV(2). 相似文献
5.
Wang CC Abe K Abe K Abe T Adachi I Aihara H Asano Y Aushev T Bakich AM Ban Y Bay A Bedny I Bitenc U Bizjak I Blyth S Bondar A Bozek A Bracko M Browder TE Chang P Chao Y Chen KF Chen WT Cheon BG Choi SK Choi Y Chuvikov A Cole S Dash M Dong LY Dragic J Drutskoy A Eidelman S Eiges V Gershon T Gokhroo G Guo R Haba J Hastings NC Hayasaka K Hayashii H Hazumi M Hokuue T Hoshi Y Hou S Hou WS Hsiung YB Iijima T Imoto A Inami K Ishikawa A Ishino H Itoh K Itoh R Iwasaki H Iwasaki Y Kakuno H Kang JH 《Physical review letters》2005,94(12):121801
We present a time-dependent analysis of CP violation in B0-->rho(+/-)pi(-/+) decays based on a 140 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at KEKB. We obtain the charge asymmetry A(rhopi)(CP)=-0.16+/-0.10(stat)+/-0.02(syst). An unbinned maximum-likelihood fit to the Deltat distributions yields C(rhopi)=0.25+/-0.17(stat)+0.02-0.06(syst), DeltaC(rhopi)=0.38+/-0.18(stat)+0.02-0.04(syst), S(rhopi)=-0.28+/-0.23(stat)+0.10-0.08(syst), and DeltaS(rhopi)=-0.30+/-0.24(stat)+/-0.09(syst). The direct CP violation parameters for B-->rho(+)pi(-) and B-->rho(-)pi(+) decays are A(+-)(rhopi)=-0.02+/-0.16(stat)+0.05-0.02(syst) and A(-+)(rhopi)=-0.53+/-0.29(stat)+0.09-0.04(syst). 相似文献
6.
Boehm F Busenitz J Cook B Gratta G Henrikson H Kornis J Lawrence D Lee KB McKinny K Miller L Novikov V Piepke A Ritchie B Tracy D Vogel P Wang YF Wolf J 《Physical review letters》2000,84(17):3764-3767
We report on the initial results from a measurement of the antineutrino flux and spectrum at a distance of about 800 m from the three reactors of the Palo Verde Nuclear Generating Station using a segmented gadolinium-loaded scintillation detector. We find that the antineutrino flux agrees with that predicted in the absence of oscillations excluding at 90% C.L. nu;(e)-nu;(x) oscillations with Deltam(2)>1.12x10(-3) eV(2) for maximal mixing and sin (2)2straight theta>0.21 for large Deltam(2). Our results support the conclusion that the atmospheric neutrino oscillations observed by Super-Kamiokande do not involve nu(e). 相似文献
7.
Abraham J Abreu P Aglietta M Aguirre C Allard D Allekotte I Allen J Allison P Alvarez-Muñiz J Ambrosio M Anchordoqui L Andringa S Anzalone A Aramo C Argirò S Arisaka K Armengaud E Arneodo F Arqueros F Asch T Asorey H Assis P Atulugama BS Aublin J Ave M Avila G Bäcker T Badagnani D Barbosa AF Barnhill D Barroso SL Baughman B Bauleo P Beatty JJ Beau T Becker BR Becker KH Bellido JA Benzvi S Berat C Bergmann T Bernardini P Bertou X Biermann PL Billoir P Blanch-Bigas O Blanco F Blasi P Bleve C 《Physical review letters》2008,101(6):061101
The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min. 相似文献
8.
Yamamoto S Zalipska J Aliu E Andringa S Aoki S Argyriades J Asakura K Ashie R Berghaus F Berns H Bhang H Blondel A Borghi S Bouchez J Burguet-Castell J Casper D Catala J Cavata C Cervera A Chen SM Cho KO Choi JH Dore U Espinal X Fechner M Fernandez E Fukuda Y Gomez-Cadenas J Gran R Hara T Hasegawa M Hasegawa T Hayashi K Hayato Y Helmer RL Hiraide K Hosaka J Ichikawa AK Iinuma M Ikeda A Inagaki T Ishida T Ishihara K Ishii T Ishitsuka M Itow Y Iwashita T Jang HI Jeon EJ Jeong IS Joo KK Jover G 《Physical review letters》2006,96(18):181801
We performed an improved search for nu(mu) --> nu(e) oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2 x 10(19) protons on target. No evidence for a nu(e) appearance signal was found, and we set bounds on the nu(mu) --> nu(e) oscillation parameters. At Deltam(2)=2.8 x 10(-3) eV(2), the best-fit value of the K2Knu(mu) disappearance analysis, we set an upper limit of sin(2)2theta(mue) < 0.13 at a 90% confidence level. 相似文献
9.
Maas FE Aulenbacher K Baunack S Capozza L Diefenbach J Gläser B Hammel T von Harrach D Imai Y Kabuss EM Kothe R Lee JH Lorente A Schilling E Schwaab D Sikora M Stephan G Weber G Weinrich C Altarev I Arvieux J El-Yakoubi M Frascaria R Kunne R Morlet M Ong S van de Wiele J Kowalski S Plaster B Suleiman R Taylor S 《Physical review letters》2005,94(15):152001
We report on a measurement of the parity violating asymmetry in the elastic scattering of polarized electrons off unpolarized protons with the A4 apparatus at MAMI in Mainz at a four momentum transfer value of Q(2)=0.108 (GeV/c)(2) and at a forward electron scattering angle of 30 degrees p)=[-1.36+/-0.29(stat)+/-0.13(syst)]x10(-6). The expectation from the standard model assuming no strangeness contribution to the vector current is A(0)=(-2.06+/-0.14)x10(-6). We have improved the statistical accuracy by a factor of 3 as compared to our previous measurements at a higher Q2. We have extracted the strangeness contribution to the electromagnetic form factors from our data to be G(s)(E)+0.106G(s)(M)=0.071+/-0.036 at Q(2)=0.108 (GeV/c)(2). We again find the value for G(s)(E)+0.106G(s)(M) to be positive, this time at an improved significance level of two sigma. 相似文献
10.
Tajima O Abe K Abe K Aihara H Akatsu M Aulchenko V Aushev T Bakich AM Bay A Bizjak I Bondar A Bozek A Bracko M Browder TE Chao Y Cheon BG Chistov R Choi Y Choi YK Chuvikov A Danilov M Dong LY Eidelman S Eiges V Fang F Gabyshev N Garmash A Gershon T Gokhroo G Haba J Hagner C Handa F Hasuko K Hazumi M Higuchi I Hokuue T Hoshi Y Hou WS Huang HC Iijima T Inami K Ishikawa A Itoh R Iwasaki Y Kang JH Kang JS Kapusta P Katayama N Kawai H Kichimi H Kim HJ Kim H Kim JH Kim SK Kinoshita K Koppenburg P 《Physical review letters》2004,92(10):101803
We report the observation of the decay D0-->phigamma with a statistical significance of 5.4sigma in 78.1 fb(-1) of data collected by the Belle experiment at the KEKB e+e- collider. This is the first observation of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and color-suppressed decays D0-->phipi(0), phieta are also observed for the first time. We measure branching fractions B(D0-->phigamma)=[2.60(+0.70)(-0.61)(stat)+0.15-0.17(syst)] x 10(-5), B(D0-->phipi(0))=[8.01+/-0.26(stat)+/-0.47(syst)] x 10(-4), and B(D0-->phieta)=[1.48+/-0.47(stat)+/-0.09(syst)] x 10(-4). 相似文献
11.
Acha A Aniol KA Armstrong DS Arrington J Averett T Bailey SL Barber J Beck A Benaoum H Benesch J Bertin PY Bosted P Butaru F Burtin E Cates GD Chao YC Chen JP Chudakov E Cisbani E Craver B Cusanno F De Leo R Decowski P Deur A Feuerbach RJ Finn JM Frullani S Fuchs SA Fuoti K Gilman R Glesener LE Grimm K Grames JM Hansen JO Hansknecht J Higinbotham DW Holmes R Holmstrom T Ibrahim H de Jager CW Jiang X Katich J Kaufman LJ Kelleher A King PM Kolarkar A Kowalski S Kuchina E Kumar KS Lagamba L 《Physical review letters》2007,98(3):032301
We report new measurements of the parity-violating asymmetry A(PV) in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with approximately 6.0 degrees . The 4He result is A(PV)=(+6.40+/-0.23(stat)+/-0.12(syst))x10(-6). The hydrogen result is A(PV)=(-1.58+/-0.12(stat)+/-0.04(syst))x10(-6). These results significantly improve constraints on the electric and magnetic strange form factors G(E)(s) and G(M)(s). We extract G(E)(s)=0.002+/-0.014+/-0.007 at
=0.077 GeV2, and G(E)(s)+0.09G(M)(s)=0.007+/-0.011+/-0.006 at=0.109 GeV2, providing new limits on the role of strange quarks in the nucleon charge and magnetization distributions. 相似文献
12.
Study of the decay B0(B- 0)-->rho+rho-, and constraints on the Cabibbo-Kobayashi-Maskawa angle alpha
Aubert B Barate R Boutigny D Couderc F Gaillard JM Hicheur A Karyotakis Y Lees JP Tisserand V Zghiche A Palano A Pompili A Chen JC Qi ND Rong G Wang P Zhu YS Eigen G Ofte I Stugu B Abrams GS Borgland AW Breon AB Brown DN Button-Shafer J Cahn RN Charles E Day CT Gill MS Gritsan AV Groysman Y Jacobsen RG Kadel RW Kadyk J Kerth LT Kolomensky YG Kukartsev G LeClerc C Lynch G Merchant AM Mir LM Oddone PJ Orimoto TJ Pripstein M Roe NA Ronan MT Shelkov VG Wenzel WA Ford K Harrison TJ Hawkes CM 《Physical review letters》2004,93(23):231801
Using a data sample of 89 x 10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC, we measure the B0(B (0))-->rho(+)rho(-) branching fraction as [30+/-4(stat)+/-5(syst)]x10(-6) and a longitudinal polarization fraction of f(L)=0.99+/-0.03(stat)+0.04-0.03(syst). We measure the time-dependent-asymmetry parameters of the longitudinally polarized component of this decay as C(L)=-0.17+/-0.27(stat)+/-0.14(syst) and S(L)=-0.42+/-0.42(stat)+/-0.14(syst). We exclude values of alpha between 19 degrees and 71 degrees (90% C.L.). 相似文献
13.
Abe Y Aberle C Akiri T dos Anjos JC Ardellier F Barbosa AF Baxter A Bergevin M Bernstein A Bezerra TJ Bezrukhov L Blucher E Bongrand M Bowden NS Buck C Busenitz J Cabrera A Caden E Camilleri L Carr R Cerrada M Chang PJ Chimenti P Classen T Collin AP Conover E Conrad JM Cormon S Crespo-Anadón JI Cribier M Crum K Cucoanes A D'Agostino MV Damon E Dawson JV Dazeley S Dierckxsens M Dietrich D Djurcic Z Dracos M Durand V Efremenko Y Elnimr M Endo Y Etenko A Falk E Fallot M Fechner M von Feilitzsch F 《Physical review letters》2012,108(13):131801
The Double Chooz experiment presents an indication of reactor electron antineutrino disappearance consistent with neutrino oscillations. An observed-to-predicted ratio of events of 0.944±0.016(stat)±0.040(syst) was obtained in 101 days of running at the Chooz nuclear power plant in France, with two 4.25 GW(th) reactors. The results were obtained from a single 10 m(3) fiducial volume detector located 1050 m from the two reactor cores. The reactor antineutrino flux prediction used the Bugey4 flux measurement after correction for differences in core composition. The deficit can be interpreted as an indication of a nonzero value of the still unmeasured neutrino mixing parameter sin(2)2θ(13). Analyzing both the rate of the prompt positrons and their energy spectrum, we find sin(2)2θ(13)=0.086±0.041(stat)±0.030(syst), or, at 90% C.L., 0.017相似文献
14.
Adamson P Andreopoulos C Arms KE Armstrong R Auty DJ Ayres DS Baller B Barnes PD Barr G Barrett WL Becker BR Belias A Bernstein RH Bhattacharya D Bishai M Blake A Bock GJ Boehm J Boehnlein DJ Bogert D Bower C Buckley-Geer E Cavanaugh S Chapman JD Cherdack D Childress S Choudhary BC Cobb JH Coleman SJ Culling AJ de Jong JK Dierckxsens M Diwan MV Dorman M Dytman SA Escobar CO Evans JJ Harris EF Feldman GJ Frohne MV Gallagher HR Godley A Goodman MC Gouffon P Gran R Grashorn EW Grossman N Grzelak K 《Physical review letters》2008,101(13):131802
This Letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum-mechanical oscillations of neutrino flavor with mass splitting |Deltam2| = (2.43+/-0.13) x 10(-3) eV2 (68% C.L.) and mixing angle sin2(2theta) > 0.90 (90% C.L.). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight: namely, neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard-deviation levels, respectively. 相似文献
15.
Distortions of cosmic microwave background temperature and polarization maps caused by gravitational lensing, observable with high angular resolution and high sensitivity, can be used to measure the neutrino mass. Assuming two massless species and one with mass m(nu), we forecast sigma(m(nu))=0.15 eV from the Planck satellite and sigma(m(nu))=0.04 eV from observations with twice the angular resolution and approximately 20 times the sensitivity. A detection is likely at this higher sensitivity since the observation of atmospheric neutrino oscillations requires Deltam(2)(nu) greater, similar (0.04 eV)(2). 相似文献
16.
Bellini G Benziger J Bick D Bonetti S Bonfini G Buizza Avanzini M Caccianiga B Cadonati L Calaprice F Carraro C Cavalcante P Chavarria A D'Angelo D Davini S Derbin A Etenko A Fomenko K Franco D Galbiati C Gazzana S Ghiano C Giammarchi M Goeger-Neff M Goretti A Grandi L Guardincerri E Hardy S Ianni A Ianni A Kobychev V Korablev D Korga G Koshio Y Kryn D Laubenstein M Lewke T Litvinovich E Loer B Lombardi F Lombardi P Ludhova L Machulin I Manecki S Maneschg W Manuzio G Meindl Q Meroni E 《Physical review letters》2011,107(14):141302
The rate of neutrino-electron elastic scattering interactions from 862 keV (7)Be solar neutrinos in Borexino is determined to be 46.0±1.5(stat)(-1.6)(+1.5)(syst)?counts/(day·100 ton). This corresponds to a ν(e)-equivalent (7)Be solar neutrino flux of (3.10±0.15)×10(9) cm(-2)?s(-1) and, under the assumption of ν(e) transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0?σ. A global solar neutrino analysis with free fluxes determines Φ(pp)=6.06(-0.06)(+0.02)×10(10) cm(-2)?s(-1) and Φ(CNO)<1.3×10(9) cm(-2)?s(-1) (95% C.L.). These results significantly improve the precision with which the Mikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy. 相似文献
17.
Aubert B Bona M Karyotakis Y Lees JP Poireau V Prencipe E Prudent X Tisserand V Garra Tico J Grauges E Lopez L Palano A Pappagallo M Eigen G Stugu B Sun L Abrams GS Battaglia M Brown DN Cahn RN Jacobsen RG Kerth LT Kolomensky YG Lynch G Osipenkov IL Ronan MT Tackmann K Tanabe T Hawkes CM Soni N Watson AT Koch H Schroeder T Walker D Asgeirsson DJ Fulsom BG Hearty C Mattison TS McKenna JA Barrett M Khan A Blinov VE Bukin AD Buzykaev AR Druzhinin VP Golubev VB Onuchin AP Serednyakov SI Skovpen YI 《Physical review letters》2008,101(7):071801
We report the results of a search for the bottomonium ground state etab(1S) in the photon energy spectrum with a sample of (109+/-1) million of Upsilon(3S) recorded at the Upsilon(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. We observe a peak in the photon energy spectrum at Egamma=921.2(-2.8)+2.1(stat)+/-2.4(syst) MeV with a significance of 10 standard deviations. We interpret the observed peak as being due to monochromatic photons from the radiative transition Upsilon(3S)-->gammaetab(1S). This photon energy corresponds to an etab(1S) mass of 9388.9(-2.3)+3.1(stat)+/-2.7(syst) MeV/c2. The hyperfine Upsilon(1S)-etab(1S) mass splitting is 71.4(-3.1)+2.3(stat)+/-2.7(syst) MeV/c2. The branching fraction for this radiative Upsilon(3S) decay is estimated to be [4.8+/-0.5(stat)+/-1.2(syst)]x10(-4). 相似文献
18.
Anthony PL Arnold RG Arroyo C Baird K Bega K Biesiada J Bosted PE Breuer M Carr R Cates GD Chen JP Chudakov E Cooke M Decker FJ Decowski P Deur A Emam W Erickson R Fieguth T Field C Gao J Gustafsson K Hicks RS Holmes R Hughes EW Humensky TB Jones GM Kaufman LJ Kolomensky YG Kumar KS Lhuillier D Lombard-Nelsen R Mastromarino P Mayer B McKeown RD Michaels R Olson M Paschke KD Peterson GA Pitthan R Pope K Relyea D Rock SE Saxton O Shapiro G Singh J Souder PA Szalata ZM Tobias WA Tonguc BT Turner J 《Physical review letters》2004,92(18):181602
We report a measurement of the parity-violating asymmetry in fixed target electron-electron (M?ller) scattering: A(PV)=[-175+/-30(stat)+/-20(syst)] x 10(-9). This first direct observation of parity nonconservation in M?ller scattering leads to a measurement of the electron's weak charge at low energy Q(e)(W)=-0.053+/-0.011. This is consistent with the standard model expectation at the current level of precision: sin((2)theta(W)(M(Z))((-)MS)=0.2293+/-0.0024(stat)+/-0.0016(syst)+/-0.0006(theory). 相似文献
19.
Abe K Abe K Abe N Abe T Adachi I Aihara H Akai K Akatsu M Akemoto M Asano Y Aso T Aulchenko V Aushev T Bakich AM Ban Y Banerjee S Bay A Bedny I Bizjak I Bondar A Bozek A Bracko M Browder TE Chao Y Chen KF Cheon BG Chistov R Choi SK Choi Y Chuvikov A Cole S Danilov M Dragic J Drutskoy A Eidelman S Eiges V Enari Y Epifanov D Flanagan J Furukawa K Gabyshev N Garmash A Gershon T Golob B Haba J Hara K Hastings NC Hayashii H Hazumi M Hinz L Hokuue T Hoshi Y Hou WS Hsiung YB Huang HC Iijima T Ikeda H 《Physical review letters》2004,93(2):021601
We report the first observation of CP violation in B0-->pi(+)pi(-) decays based on 152x10(6) gamma (4S)-->BB decays collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We reconstruct a B0-->pi(+)pi(-) CP eigenstate and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two B meson decay points, we obtain A(pipi)=+0.58+/-0.15(stat)+/-0.07(syst) and S(pipi)=-1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, A(pipi)=S(pipi)=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any S(pipi) value. 相似文献
20.
Aubert B Barate R Boutigny D Couderc F Gaillard JM Hicheur A Karyotakis Y Lees JP Tisserand V Zghiche A Palano A Pompili A Chen JC Qi ND Rong G Wang P Zhu YS Eigen G Ofte I Stugu B Abrams GS Borgland AW Breon AB Brown DN Button-Shafer J Cahn RN Charles E Day CT Gill MS Gritsan AV Groysman Y Jacobsen RG Kadel RW Kadyk J Kerth LT Kolomensky YG Kukartsev G LeClerc C Lynch G Merchant AM Mir LM Oddone PJ Orimoto TJ Pripstein M Roe NA Ronan MT Shelkov VG Telnov AV Wenzel WA Ford K Harrison TJ 《Physical review letters》2004,93(7):071801
We present a measurement of the time-dependent CP asymmetry for the neutral B-meson decay B0-->phiK0. We use a sample of approximately 114 x 10(6) B-meson pairs taken at the Upsilon(4S) resonance with the BABAR detector at the PEP-II B-meson factory at SLAC. We reconstruct the CP eigenstates phiK0S and phiK0L, where phi-->K+K-, K0S-->pi+pi-, and K0L is observed via its hadronic interactions. The other B meson in the event is tagged as either a B0 or Bbar0 from its decay products. The values of the CP-violation parameters are SphiK=0.47+/-0.34(stat)+0.08-0.06(syst) and CphiK=0.01+/-0.33(stat)+/-0.10(syst). 相似文献