共查询到20条相似文献,搜索用时 578 毫秒
1.
Adamson P Auty DJ Ayres DS Backhouse C Barr G Bishai M Blake A Bock GJ Boehnlein DJ Bogert D Cavanaugh S Cherdack D Childress S Coelho JA Coleman SJ Corwin L Cronin-Hennessy D Danko IZ de Jong JK Devenish NE Diwan MV Dorman M Escobar CO Evans JJ Falk E Feldman GJ Frohne MV Gallagher HR Gomes RA Goodman MC Gouffon P Graf N Gran R Grant N Grzelak K Habig A Harris D Hartnell J Hatcher R Himmel A Holin A Huang X Hylen J Ilic J Irwin GM Isvan Z Jaffe DE James C Jensen D Kafka T Kasahara SM Koizumi G 《Physical review letters》2011,107(1):011802
Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of 7.07×10(20) protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of 754 ± 28(stat) ± 37(syst) for oscillations among three active flavors. The fraction f(s) of disappearing ν(μ) that may transition to ν(s) is found to be less than 22% at the 90% C.L. 相似文献
2.
Bellini G Benziger J Bick D Bonetti S Bonfini G Bravo D Buizza Avanzini M Caccianiga B Cadonati L Calaprice F Carraro C Cavalcante P Chavarria A Chepurnov 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 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》2012,108(5):051302
We observed, for the first time, solar neutrinos in the 1.0-1.5 MeV energy range. We determined the rate of pep solar neutrino interactions in Borexino to be 3.1±0.6{stat}±0.3{syst} counts/(day·100 ton). Assuming the pep neutrino flux predicted by the standard solar model, we obtained a constraint on the CNO solar neutrino interaction rate of <7.9 counts/(day·100 ton) (95% C.L.). The absence of the solar neutrino signal is disfavored at 99.97% C.L., while the absence of the pep signal is disfavored at 98% C.L. The necessary sensitivity was achieved by adopting data analysis techniques for the rejection of cosmogenic {11}C, the dominant background in the 1-2 MeV region. Assuming the Mikheyev-Smirnov-Wolfenstein large mixing angle solution to solar neutrino oscillations, these values correspond to solar neutrino fluxes of (1.6±0.3)×10{8} cm{-2}?s^{-1} and <7.7×10{8} cm{-2}?s{-1} (95% C.L.), respectively, in agreement with both the high and low metallicity standard solar models. These results represent the first direct evidence of the pep neutrino signal and the strongest constraint of the CNO solar neutrino flux to date. 相似文献
3.
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
4.
Abe K Hayato Y Iida T Ikeda M Iyogi K Kameda J Koshio Y Kozuma Y Miura M Moriyama S Nakahata M Nakayama S Obayashi Y Sekiya H Shiozawa M Suzuki Y Takeda A Takenaga Y Takeuchi Y Ueno K Ueshima K Watanabe H Yamada S Yokozawa T Ishihara C Kaji H Lee KP Kajita T Kaneyuki K McLachlan T Okumura K Shimizu Y Tanimoto N Martens K Vagins MR Labarga L Magro LM Dufour F Kearns E Litos M Raaf JL Stone JL Sulak LR Goldhaber M Bays K Kropp WR Mine S Regis C Smy MB Sobel HW Ganezer KS Hill J Keig WE Jang JS 《Physical review letters》2011,107(24):241801
We present a search for differences in the oscillations of antineutrinos and neutrinos in the Super-Kamiokande-I, -II, and -III atmospheric neutrino sample. Under a two-flavor disappearance model with separate mixing parameters between neutrinos and antineutrinos, we find no evidence for a difference in oscillation parameters. Best-fit antineutrino mixing is found to be at (Δm2,sin2 2θ)=(2.0×10(-3) eV2, 1.0) and is consistent with the overall Super-K measurement. 相似文献
5.
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
6.
Friedland A 《Physical review letters》2000,85(5):936-939
We point out that for solar neutrino oscillations with the mass-squared difference of Deltam(2) approximately 10(-10)-10(-9) eV(2), i.e., in the so-called vacuum oscillation range, the solar matter effects are non-negligible, particularly for the low energy pp neutrinos. One consequence of this is that the values of the mixing angle straight theta and pi/2-straight theta are not equivalent, making it necessary to consider the entire physical range of the mixing angle 0=straight theta=pi/2 when determining the allowed values of the neutrino oscillation parameters. 相似文献
7.
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
8.
Numerical simulations for the merger of binary neutron stars are performed in full general relativity incorporating a finite-temperature (Shen's) equation of state (EOS) and neutrino cooling for the first time. It is found that for this stiff EOS, a hypermassive neutron star (HMNS) with a long lifetime (?10 ms) is the outcome for the total mass ?3.0M(⊙). It is shown that the typical total neutrino luminosity of the HMNS is ~3-8×10(53) erg/s and the effective amplitude of gravitational waves from the HMNS is 4-6×10(-22) at f=2.1-2.5 kHz for a source distance of 100 Mpc. We also present the neutrino luminosity curve when a black hole is formed for the first time. 相似文献
9.
The superluminal neutrinos detected by OPERA indicate Lorentz invariance violation (LIV) of the neutrino sector at the order of 10(-5). We study the implications of the result in this work. We find that such a large LIV implied by OPERA data will make the neutrino production process π → μ + ν(μ) kinematically forbidden for a neutrino energy greater than about 5 GeV. The OPERA detection of neutrinos at 40 GeV can constrain the LIV parameter to be smaller than 3×10(-7). Furthermore, the neutrino decay in the LIV framework will modify the neutrino spectrum greatly. The atmospheric neutrino spectrum measured by the IceCube Collaboration can constrain the LIV parameter to the level of 10(-12). The future detection of astrophysical neutrinos of galactic sources is expected to be able to give an even stronger constraint on the LIV parameter of neutrinos. 相似文献
10.
Recent observations of neutrino oscillations imply nonzero neutrino masses and lepton flavor violation (LFV), most economically explained by the seesaw mechanism. Within the context of supersymmetry, LFV among the neutrinos can be communicated to the sleptons and from there to the charged leptons. We show that LFV can appear in the couplings of the neutral Higgs bosons, an effect that is strongly enhanced at large tan(beta. We calculate the branching fraction for tau-->3micro and micro-->3e mediated by Higgs and find they can be as large as 10(-7) and 5x10(-14), respectively. These modes, along with tau-->mugamma and mu-->egamma, can provide key insights into the neutrino mass matrix. 相似文献
11.
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
12.
13.
Abe K Hayato Y Iida T Ishihara K Kameda J Koshio Y Minamino A Mitsuda C Miura M Moriyama S Nakahata M Obayashi Y Ogawa H Shiozawa M Suzuki Y Takeda A Takeuchi Y Ueshima K Higuchi I Ishihara C Ishitsuka M Kajita T Kaneyuki K Mitsuka G Nakayama S Nishino H Okumura K Saji C Takenaga Y Totsuka Y Clark S Desai S Dufour F Kearns E Likhoded S Litos M Raaf JL Stone JL Sulak LR Wang W Goldhaber M Casper D Cravens JP Kropp WR Liu DW Mine S Regis C Smy MB Sobel HW Vagins MR Ganezer KS Hill JE Keig WE 《Physical review letters》2006,97(17):171801
A search for the appearance of tau neutrinos from nu(mu) <--> nu(tau) oscillations in the atmospheric neutrinos has been performed using 1489.2 days of atmospheric neutrino data from the Super-Kamiokande-I experiment. A best fit tau neutrino appearance signal of 138+/-48(stat)-32(+15)(syst) events is obtained with an expectation of 78+/-26(syst). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma. 相似文献
14.
We analyse the structure of the neutrino mass matrix and the pattern of neutrino oscillations in the O(10) model with radiatively induced Majorana masses. In particular, we show that the possibility of experimentally interesting neutrino oscillations is left open. 相似文献
15.
A. I. Studenikin 《Physics of Atomic Nuclei》2004,67(5):993-1002
The history of the development of the theory of neutrino-flavor and neutrino-spin oscillations in electromagnetic fields and in a medium is briefly surveyed. A new Lorentz-invariant approach to describing neutrino oscillations in a medium is formulated in such a way that it makes it possible to consider the motion of a medium at an arbitrary velocity, including relativistic ones. This approach permits studying neutrinospin oscillations under the effect of an arbitrary external electromagnetic field. In particular, it is predicted that, in the field of an electromagnetic wave, new resonances may exist in neutrino oscillations. In the case of spin oscillations in various electromagnetic fields, the concept of a critical magnetic-field-component strength is introduced above which the oscillations become sizable. In considering neutrino oscillations in moving matter, it is shown within the Lorentz-invariant formalism that the relativistic motion of matter significantly affects the character of neutrino oscillations and can radically change the conditions under which the oscillations are resonantly enhanced. Possible new effects in neutrino oscillations are discussed for the case of neutrino propagation in relativistic fluxes of matter. 相似文献
16.
Kh. M. Beshtoev 《Physics of Particles and Nuclei Letters》2007,4(6):471-476
In the standard theory of neutrino oscillations, it is supposed that physically observed neutrino states ν
e
, νμ, ντ, have no definite masses, that they are initially produced as a mixture of the ν1, ν2, ν3 neutrino states (i.e., they are produced as a wave packet), and that neutrino oscillations are the real ones. Then, this
wave packet must decompose at a definite distance into constituent parts and neutrino oscillations must disappear. It was
shown that these suppositions lead to violation of the law of energy and momentum conservation. An alternative scheme of neutrino
oscillations obtained within the framework of particle physics has been considered, where the above mentioned shortcomings
are absent, the oscillations of neutrinos with equal masses are the real ones, and the oscillations of neutrinos with different
masses are the virtual ones. Expressions for probabilities of neutrino transitions (oscillations) in the alternative (corrected)
scheme are given.
The text was submitted by the author in English. 相似文献
17.
J G Learned 《Pramana》2000,55(1-2):3-18
With the announcement of new evidence for muon neutrino disappearance observed by the super-Kamiokande experiment, the more
than a decade old atmospheric neutrino anomaly moved from a possible indication for neutrino oscillations to an apparently
inescapable fact. The evidence is reviewed, and new indications are presented that the oscillations are probably between muon
and tau neutrinos. Implications and future directions are discussed. 相似文献
18.
Physics of Atomic Nuclei - The theory of neutrino oscillations rests on the assumption, that the interaction basis and the physical (mass) basis of neutrino states are different. Therefore neutrino... 相似文献
19.
Abe K Abgrall N Ajima Y Aihara H Albert JB Andreopoulos C Andrieu B Aoki S Araoka O Argyriades J Ariga A Ariga T Assylbekov S Autiero D Badertscher A Barbi M Barker GJ Barr G Bass M Bay F Bentham S Berardi V Berger BE Bertram I Besnier M Beucher J Beznosko D Bhadra S Blaszczyk FM Blondel A Bojechko C Bouchez J Boyd SB Bravar A Bronner C Brook-Roberge DG Buchanan N Budd H Calvet D Cartwright SL Carver A Castillo R Catanesi MG Cazes A Cervera A Chavez C Choi S Christodoulou G Coleman J Coleman W 《Physical review letters》2011,107(4):041801
The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3) eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy. 相似文献
20.
Adamson P Auty DJ Ayres DS Backhouse C Barr G Betancourt M Bishai M Blake A Bock GJ Boehnlein DJ Bogert D Cao SV Cavanaugh S Cherdack D Childress S Coelho JA Corwin L Cronin-Hennessy D Danko IZ de Jong JK Devenish NE Diwan MV Dorman M Escobar CO Evans JJ Falk E Feldman GJ Frohne MV Gallagher HR Gomes RA Goodman MC Gouffon P Graf N Gran R Grzelak K Habig A Hartnell J Hatcher R Himmel A Holin A Huang X Hylen J Irwin GM Isvan Z Jaffe DE James C Jensen D Kafka T Kasahara SM Koizumi G Kopp S 《Physical review letters》2011,107(18):181802
We report the results of a search for ν(e) appearance in a ν(μ) beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of 8.2 × 10(20) protons on the NuMI target at Fermilab, we find that 2 sin(2) (θ(23))sin(2)(2θ(13))<0.12(0.20) at 90% confidence level for δ = 0 and the normal (inverted) neutrino mass hierarchy, with a best-fit of 2sin(2) (θ(23))sin(2)(2θ(13)) = 0.041(-0.031)(+0.047) (0.079(-0.053) (+0.071)). The θ(13) = 0 hypothesis is disfavored by the MINOS data at the 89% confidence level. 相似文献