共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
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
3.
We consider the consequences for future neutrino factory experiments of small CPT-odd interactions in neutrino oscillations. The nu(&mgr;)-->nu(&mgr;) and nu;(&mgr;)-->nu;(&mgr;) survival probabilities at a baseline L = 732 km can test for CPT-odd contributions at orders of magnitude better sensitivity than present neutrino sector limits. Interference between the CPT-violating interaction and CPT-even mass terms in the Lagrangian can lead to a resonant enhancement of the oscillation amplitude. For oscillations in matter, a simultaneous enhancement of both neutrino and antineutrino oscillation amplitudes is possible. 相似文献
4.
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
5.
Eguchi K Enomoto S Furuno K Ikeda H Ikeda K 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 Piquemal F Shimizu I Shirai J Suekane F Suzuki A Tada K Tajima O Takayama T Tamae K Watanabe H Busenitz J Djurcic Z McKinny K Mei DM Piepke A Yakushev E Berger BE Chan YD Decowski MP Dwyer DA Freedman SJ Fu Y Fujikawa BK Goldman J Heeger KM Lesko KT Luk KB Murayama H Nygren DR Okada CE Poon AW Steiner HM Winslow LA Horton-Smith GA 《Physical review letters》2004,92(7):071301
Data corresponding to a KamLAND detector exposure of 0.28 kton yr has been used to search for nu;(e)'s in the energy range 8.3相似文献
6.
Eguchi K Enomoto S Furuno K Goldman J Hanada H Ikeda H Ikeda K Inoue K Ishihara K Itoh W Iwamoto T Kawaguchi T Kawashima T Kinoshita H Kishimoto Y Koga M Koseki Y Maeda T Mitsui T Motoki M Nakajima K Nakajima M Nakajima T Ogawa H Owada K Sakabe T Shimizu I Shirai J Suekane F Suzuki A Tada K Tajima O Takayama T Tamae K Watanabe H Busenitz J Djurcic Z McKinny K Mei DM Piepke A Yakushev E Berger BE Chan YD Decowski MP Dwyer DA Freedman SJ Fu Y Fujikawa BK Heeger KM Lesko KT Luk KB Murayama H 《Physical review letters》2003,90(2):021802
KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded. 相似文献
7.
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
8.
Abe S Ebihara T Enomoto S Furuno K Gando Y Ichimura K Ikeda H Inoue K Kibe Y Kishimoto Y Koga M Kozlov A Minekawa Y Mitsui T Nakajima K Nakajima K Nakamura K Nakamura M Owada K Shimizu I Shimizu Y Shirai J Suekane F Suzuki A Takemoto Y Tamae K Terashima A Watanabe H Yonezawa E Yoshida S Busenitz J Classen T Grant C Keefer G Leonard DS McKee D Piepke A Decowski MP Detwiler JA Freedman SJ Fujikawa BK Gray F Guardincerri E Hsu L Kadel R Lendvai C Luk KB Murayama H O'Donnell T Steiner HM Winslow LA 《Physical review letters》2008,100(22):221803
The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06. 相似文献
9.
We have solved the evolution equation for neutrinos in a low density medium, Vnu(e), we have found the attenuation effect: a decrease of the sensitivity to remote structures, d>l(nu)E/DeltaE, where l(nu) is the oscillation length and DeltaE/E is the energy resolution of a detector. 相似文献
10.
Hara K Hazumi M Abe K Abe K Abe T Adachi I Ahn BS Aihara H Akatsu M Asano Y Aso T Aulchenko V Aushev T Bakich AM Ban Y Bay A Bedny I Behera PK Bizjak I Bondar A Bozek A Bracko M Brodzicka J Browder TE Casey BC Chang P Chao Y Chen KF Cheon BG Chistov R Choi SK Choi Y Choi YK Danilov M Dong LY Dragic J Eidelman S Eiges V Enari Y Everton CW Fang F Fukunaga C Gabyshev N Garmash A Gershon T Golob B Guo R Haba J Hanagaki K Handa F Hara T Hastings NC Hayashii H Heenan EM Higuchi I Higuchi T Hinz L 《Physical review letters》2002,89(25):251803
We present a measurement of the B0-Bmacr;(0) mixing parameter Deltam(d) using neutral B meson pairs in a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We exclusively reconstruct one neutral B meson in the semileptonic B0-->D(*-)l(+)nu decay mode and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two flavor-tagged B meson decay points, we obtain Deltam(d)=(0.494+/-0.012+/-0.015) ps(-1), where the first error is statistical and the second error is systematic. 相似文献
11.
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
12.
Avvakumov S Adams T Alton A de Barbaro L de Barbaro P Bernstein RH Bodek A Bolton T Brau J Buchholz D Budd H Bugel L Conrad J Drucker RB Fleming BT Frey R Formaggio JA Goldman J Goncharov M Harris DA Johnson RA Kim JH Koutsoliotas S Lamm MJ Marsh W Mason D McDonald J McFarland KS McNulty C Naples D Nienaber P Radescu V Romosan A Sakumoto WK Schellman H Shaevitz MH Spentzouris P Stern EG Suwonjandee N Tzanov M Vakili M Vaitaitis A Yang UK Yu J Zeller GP Zimmerman ED 《Physical review letters》2002,89(1):011804
Limits on nu(mu)-->nu(e) and nu(mu)-->nu(e) oscillations are extracted using the NuTeV detector with sign-selected nu(mu) and nu(mu) beams. In nu(mu) mode, for the case of sin(2)2alpha = 1, Delta(m)(2)>2.6 eV(2) is excluded, and for Delta(m)(2)>1000 eV(2), sin(2)2alpha>1.1 x 10(-3). The NuTeV data exclude the high Delta(m)(2) end of nu(mu)-->nu(e) oscillation parameters favored by the LSND experiment without the need to assume that the oscillation parameters for nu and nu are the same. We present the most stringent experimental limits for nu(mu)(nu(mu))-->nu(e)(nu(e)) oscillations in the large Delta(m)(2) region. 相似文献
13.
We use the recent KamLAND observations to predict the solar antineutrino spectrum at some confidence limits. We find a scaling of the antineutrino probability with respect to the magnetic field profile—in the sense that the same probability function can be reproduced by any profile with a suitable peak field value—that can be utilized to obtain the general shape ofthe solar antineutrino spectrum. This scaling and the upper bound on the solar antineutrino event rate, which can be derived from the data, lead to: 1) an upper bound on the solar antineutrino flux and 2) the prediction of their energy spectrum. We get \(\phi _{\bar \nu } < 3.8 \times 10^{ - 3} \phi (^8 B)\) or \(\phi _{\bar \nu } < 5.5 \times 10^{ - 3} \phi (^8 B)\) at 95% C.L., assuming Gaussian or Poissonian statistics, respectively. For 90% C.L., these become \(\phi _{\bar \nu } < 3.4 \times 10^{ - 3} \phi (^8 B)\) and \(\phi _{\bar \nu } < 4.9 \times 10^{ - 3} \phi (^8 B)\). This provides an improvement by a factor of 3–5 with respect to the existing bounds. These limits are quite general and independent of the detailed structure of the magnetic field in the solar interior. 相似文献
14.
Ashie Y Hosaka J Ishihara K Itow Y Kameda J Koshio Y Minamino A Mitsuda C Miura M Moriyama S Nakahata M Namba T Nambu R Obayashi Y Shiozawa M Suzuki Y Takeuchi Y Taki K Yamada S Ishitsuka M Kajita T Kaneyuki K Nakayama S Okada A Okumura K Ooyabu T Saji C Takenaga Y Desai S Kearns E Likhoded S Stone JL Sulak LR Walter CW Wang W Goldhaber M Casper D Cravens JP Gajewski W Kropp WR Liu DW Mine S Smy MB Sobel HW Sterner CW Vagins MR Ganezer KS Hill J Keig WE Jang JS Kim JY Lim IT Ellsworth RW 《Physical review letters》2004,93(10):101801
Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu(micro)<-->nu(tau) neutrino oscillation parameters; 1.9x10(-3)0.90 at 90% confidence level. 相似文献
15.
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
16.
We discuss the impact of different solar neutrino data on the spin-flavor-precession (SFP) mechanism of neutrino conversion. We find that, although detailed solar rates and spectra allow the SFP solution as a subleading effect, the recent KamLAND constraint on the solar antineutrino flux places stronger constraints on this mechanism. Moreover, we show that for the case of random magnetic fields inside the Sun, one obtains a more stringent constraint on the neutrino magnetic moment down to the level of mu(nu)< or = few x 10(-12)mu(B), similar to bounds obtained from star cooling. 相似文献
17.
Ahmad QR Allen RC Andersen TC Anglin JD Bühler G Barton JC Beier EW Bercovitch M Bigu J Biller S Black RA Blevis I Boardman RJ Boger J Bonvin E Boulay MG Bowler MG Bowles TJ Brice SJ Browne MC Bullard TV Burritt TH Cameron K Cameron J Chan YD Chen M Chen HH Chen X Chon MC Cleveland BT Clifford ET Cowan JH Cowen DF Cox GA Dai Y Dai X Dalnoki-Veress F Davidson WF Doe PJ Doucas G Dragowsky MR Duba CA Duncan FA Dunmore J Earle ED Elliott SR Evans HC Ewan GT Farine J Fergani H Ferraris AP Ford RJ 《Physical review letters》2001,87(7):071301
Solar neutrinos from (8)B decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of nu(e)'s is measured by the CC reaction rate to be straight phi(CC)(nu(e)) = 1.75 +/- 0.07(stat)(+0.12)(-0.11)(syst) +/- 0.05(theor) x 10(6) cm(-2) s(-1). Comparison of straight phi(CC)(nu(e)) to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a 3.3 sigma difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- nu(e) component in the solar flux. The total flux of active 8B neutrinos is determined to be 5.44+/-0.99 x 10(6) cm(-2) s(-1). 相似文献
18.
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
19.
A. P. Serebrov V. G. Ivochkin R. M. Samoylov A. K. Fomin V. G. Zinoviev P. V. Neustroev V. L. Golovtsov N. V. Gruzinsky V. A. Solovey A. V. Cherniy O. M. Zherebtsov V. P. Martemyanov V. G. Zinoev V. G. Tarasenkov V. I. Aleshin A. L. Petelin S. V. Pavlov A. L. Izhutov S. A. Sazontov D. K. Ryazanov M. O. Gromov V. V. Afanasiev L. N. Matrosov M. Yu. Matrosova 《Physics of Particles and Nuclei》2016,47(6):1014-1023
In connection with the question of possible existence of sterile neutrino the laboratory on the basis of SM-3 reactor was created to search for oscillations of reactor antineutrino. A prototype of a neutrino detector with scintillator volume of 400 l can be moved at the distance of 6–11 m from the reactor core. The measurements of background conditions have been made. It is shown that the main experimental problem is associated with cosmic radiation background. Test measurements of dependence of a reactor antineutrino flux on the distance from a reactor core have been made. The prospects of search for oscillations of reactor antineutrino at short distances are discussed. 相似文献
20.
Viehhauser G Wang JC Wolf A Wu J Csorna SE McLean KW Marka S Xu Z Godang R Kinoshita K Lai IC Schrenk S Bonvicini G Cinabro D Greene R Perera LP Zhou GJ Chan S Eigen G Lipeles E Schmidtler M Shapiro A Sun WM Urheim J Weinstein AJ Wurthwein F 《Physical review letters》2000,84(5):830-834
Using 4.68 fb(-1) of e(+)e(-) annihilation data collected with the CLEO II detector at the Cornell Electron Storage Ring, we have studied tau radiative decays tau(-)-->nu(tau)&mgr;(-)nu;(&mgr;)gamma and tau(-)-->nu(tau)e(-)nu;(e)gamma. For a 10 MeV minimum photon energy in the tau rest frame, the branching fraction for radiative tau decay to a muon or electron is measured to be (3.61+/-0.16+/-0. 35)x10(-3) or (1.75+/-0.06+/-0.17)x10(-2), respectively. The branching fractions are in agreement with standard model theoretical predictions. 相似文献