Author: "Hor, YK" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Hor, YK"' showing total 48 results

Start Over Author "Hor, YK"

48 results on '"Hor, YK"'

1. Improved Measurement of the Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Author: An, FP, Bai, WD, Balantekin, AB, Bishai, M, Blyth, S, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, HY, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, Y-C, Cheng, ZK, Cherwinka, JJ, Chu, MC, Cummings, JP, Dalager, O, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dolzhikov, D, Dove, J, Dugas, KV, Duyang, HY, Dwyer, DA, Gallo, JP, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Han, Y, Hans, S, He, M, Heeger, KM, Heng, YK, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, JH, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, HL, Li, JJ, Li, QJ, Li, RH, Li, S, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, JX, Lu, C, Lu, HQ, and Luk, KB
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Nuclear Reactors, Uranium, Daya Bay Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. In this Letter, the evolution of the flux and spectrum as a function of the reactor isotopic content is reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as the flux evolution with the ^{239}Pu isotopic fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted inverse-beta-decay spectrum from ^{239}Pu fission does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to ^{235}U fission is changed or the predicted ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu spectra are changed in equal measure.
Published: 2023

2. Precision Measurement of Reactor Antineutrino Oscillation at Kilometer-Scale Baselines by Daya Bay

Author: An, FP, Bai, WD, Balantekin, AB, Bishai, M, Blyth, S, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, HY, Chen, SM, Chen, Y, Chen, YX, Chen, ZY, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Cummings, JP, Dalager, O, Deng, FS, Ding, YY, Ding, XY, Diwan, MV, Dohnal, T, Dolzhikov, D, Dove, J, Duyang, HY, Dwyer, DA, Gallo, JP, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Han, Y, Hans, S, He, M, Heeger, KM, Heng, YK, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, JH, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, HL, Li, JJ, Li, QJ, Li, RH, Li, S, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, JX, Lu, C, Lu, HQ, Luk, KB, and Z., B
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Daya Bay Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: We present a new determination of the smallest neutrino mixing angle θ_{13} and the mass-squared difference Δm_{32}^{2} using a final sample of 5.55×10^{6} inverse beta-decay (IBD) candidates with the final-state neutron captured on gadolinium. This sample is selected from the complete dataset obtained by the Daya Bay reactor neutrino experiment in 3158 days of operation. Compared to the previous Daya Bay results, selection of IBD candidates has been optimized, energy calibration refined, and treatment of backgrounds further improved. The resulting oscillation parameters are sin^{2}2θ_{13}=0.0851±0.0024, Δm_{32}^{2}=(2.466±0.060)×10^{-3} eV^{2} for the normal mass ordering or Δm_{32}^{2}=-(2.571±0.060)×10^{-3} eV^{2} for the inverted mass ordering.
Published: 2023

3. First Measurement of High-Energy Reactor Antineutrinos at Daya Bay

Author: An, FP, Bai, WD, Balantekin, AB, Bishai, M, Blyth, S, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, HY, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Cummings, JP, Dalager, O, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dolzhikov, D, Dove, J, Dwyer, DA, Gallo, JP, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, JH, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, HL, Li, JJ, Li, QJ, Li, RH, Li, S, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, JX, Lu, C, Lu, HQ, Luk, KB, Z., B, B., X, Y., X, Q., Y, and Mandujano, RC
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Affordable and Clean Energy, Daya Bay Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12 MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10 MeV is rejected with a significance of 6.2 standard deviations. A 29% antineutrino flux deficit in the prompt energy region of 8-11 MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-Q_{β} isotopes in commercial reactors.
Published: 2022

4. Joint Determination of Reactor Antineutrino Spectra from U235 and Pu239 Fission by Daya Bay and PROSPECT

Author: An, FP, Andriamirado, M, Balantekin, AB, Band, HR, Bass, CD, Bergeron, DE, Berish, D, Bishai, M, Blyth, S, Bowden, NS, Bryan, CD, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Classen, T, Conant, AJ, Cummings, JP, Dalager, O, Deichert, G, Delgado, A, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dolinski, MJ, Dolzhikov, D, Dove, J, Dvořák, M, Dwyer, DA, Erickson, A, Foust, BT, Gaison, JK, Galindo-Uribarri, A, Gallo, JP, Gilbert, CE, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, Hansell, AB, He, M, Heeger, KM, Heffron, B, Heng, YK, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, JH, Huang, XT, Huang, YB, Huber, P, Koblanski, J, Jaffe, DE, Jayakumar, S, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, DC, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kyzylova, O, Lane, CE, Langford, TJ, LaRosa, J, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, HL, Li, JJ, Li, QJ, Li, RH, Li, S, and Li, SC
Subjects: Nuclear and Plasma Physics, Engineering, Synchrotrons and Accelerators, Physical Sciences, Daya Bay Collaboration, PROSPECT Collaboration, Mathematical Sciences, General Physics, Mathematical sciences, Physical sciences
Abstract: A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.
Published: 2022

5. Antineutrino energy spectrum unfolding based on the Daya Bay measurement and its applications * *Supported in part by the Ministry of Science and Technology of China, the U.S. Department of Energy, the Chinese Academy of Sciences, the CAS Center for Excellence in Particle Physics, the National Natural Science Foundation of China, the Guangdong provincial government, the Shenzhen municipal government, the China General Nuclear Power Group, the Research Grants Council of the Hong Kong Special Administrative Region of China, the Ministry of Education in TW, the U.S. National Science Foundation, the Ministry of Education, Youth, and Sports of the Czech Republic, the Charles University Research Centre UNCE, the Joint Institute of Nuclear Research in Dubna, Russia, the National Commission of Scientific and Technological Research of Chile

Author: An, FP, Balantekin, AB, Bishai, M, Blyth, S, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Cummings, JP, Dalager, O, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dolzhikov, D, Dove, J, Dvořák, M, Dwyer, DA, Gallo, JP, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, JH, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, HL, Li, JJ, Li, QJ, Li, RH, Li, S, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, JX, Lu, C, Lu, HQ, Luk, KB, Z., B, B., X, Y., X, Q., Y, and Mandujano, RC
Subjects: Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Affordable and Clean Energy, reactor antineutrino, energy spectrum, Daya Bay, application, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: The prediction of reactor antineutrino spectra will play a crucial role as reactor experiments enter the precision era. The positron energy spectrum of 3.5 million antineutrino inverse beta decay reactions observed by the Daya Bay experiment, in combination with the fission rates of fissile isotopes in the reactor, is used to extract the positron energy spectra resulting from the fission of specific isotopes. This information can be used to produce a precise, data-based prediction of the antineutrino energy spectrum in other reactor antineutrino experiments with different fission fractions than Daya Bay. The positron energy spectra are unfolded to obtain the antineutrino energy spectra by removing the contribution from detector response with the Wiener-SVD unfolding method. Consistent results are obtained with other unfolding methods. A technique to construct a data-based prediction of the reactor antineutrino energy spectrum is proposed and investigated. Given the reactor fission fractions, the technique can predict the energy spectrum to a 2% precision. In addition, we illustrate how to perform a rigorous comparison between the unfolded antineutrino spectrum and a theoretical model prediction that avoids the input model bias of the unfolding method.
Published: 2021

6. Search for electron-Antineutrinos associated with gravitational-wave events GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817 at Daya Bay

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Cummings, JP, Dalager, O, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dove, J, Dvořák, M, Dwyer, DA, Gallo, JP, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, JJ, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Lu, C, Lu, HQ, Lu, JS, Luk, KB, Ma, XB, Ma, XY, Ma, YQ, Marshall, C, Martinez Caicedo, DA, McDonald, KT, McKeown, RD, and Meng, Y
Subjects: gravitational waves, electron-antineutrinos, fluence, upper limit, astro-ph.HE, hep-ex, physics.ins-det, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The establishment of a possible connection between neutrino emission and gravitational-wave (GW) bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge. In the Daya Bay experiment, using the data collected from December 2011 to August 2017, a search was performed for electron-Antineutrino signals that coincided with detected GW events, including GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817. We used three time windows of 10, 500, and 1000 s relative to the occurrence of the GW events and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates. The detected electron-Antineutrino candidates were consistent with the expected background rates for all the three time windows. Assuming monochromatic spectra, we found upper limits (90% confidence level) of the electron-Antineutrino fluence of (1.13-2.44)×1011 cm-2 at 5 MeV to 8.0×107 cm-2 at 100 MeV for the three time windows. Under the assumption of a Fermi-Dirac spectrum, the upper limits were found to be (5.4-7.0)×109 cm-2 for the three time windows.
Published: 2021

7. Antineutrino Energy Spectrum Unfolding Based on the Daya Bay Measurement and Its Applications

Author: collaboration, Daya Bay, An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Cummings, JP, Dalager, O, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dove, J, Dvorak, M, Dwyer, DA, Gallo, JP, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, JJ, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Lu, C, Lu, HQ, Lu, JS, Luk, KB, Ma, XB, Ma, XY, Ma, YQ, Marshall, C, Caicedo, DA Martinez, McDonald, KT, and McKeown, RD
Subjects: hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: The prediction of reactor antineutrino spectra will play a crucial role asreactor experiments enter the precision era. The positron energy spectrum of3.5 million antineutrino inverse beta decay reactions observed by the Daya Bayexperiment, in combination with the fission rates of fissile isotopes in thereactor, is used to extract the positron energy spectra resulting from thefission of specific isotopes. This information can be used to produce aprecise, data-based prediction of the antineutrino energy spectrum in otherreactor antineutrino experiments with different fission fractions than DayaBay. The positron energy spectra are unfolded to obtain the antineutrino energyspectra by removing the contribution from detector response with the Wiener-SVDunfolding method. Consistent results are obtained with other unfolding methods.A technique to construct a data-based prediction of the reactor antineutrinoenergy spectrum is proposed and investigated. Given the reactor fissionfractions, the technique can predict the energy spectrum to a 2% precision. Inaddition, we illustrate how to perform a rigorous comparison between theunfolded antineutrino spectrum and a theoretical model prediction that avoidsthe input model bias of the unfolding method.
Published: 2021

8. Improved Constraints on Sterile Neutrino Mixing from Disappearance Searches in the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments

Author: Adamson, P, An, FP, Anghel, I, Aurisano, A, Balantekin, AB, Band, HR, Barr, G, Bishai, M, Blake, A, Blyth, S, Cao, GF, Cao, J, Cao, SV, Carroll, TJ, Castromonte, CM, Chang, JF, Chang, Y, Chen, HS, Chen, R, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Childress, S, Chu, MC, Chukanov, A, Coelho, JAB, Cummings, JP, Dash, N, De Rijck, S, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dolzhikov, D, Dove, J, Dvořák, M, Dwyer, DA, Evans, JJ, Feldman, GJ, Flanagan, W, Gabrielyan, M, Gallo, JP, Germani, S, Gomes, RA, Gonchar, M, Gong, GH, Gong, H, Gouffon, P, Graf, N, Grzelak, K, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Habig, A, Hackenburg, RW, Hahn, SR, Hans, S, Hartnell, J, Hatcher, R, He, M, Heeger, KM, Heng, YK, Higuera, A, Holin, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, J, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Koerner, LW, Kohn, S, Kordosky, M, Kramer, M, Kreymer, A, Lang, K, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, and Leitner, R
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Daya Bay Collaboration, MINOS+ Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θ_{μe} mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm_{41}^{2}, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CL_{s} for Δm_{41}^{2}
Published: 2020

9. A high precision calibration of the nonlinear energy response at Daya Bay

Author: Adey, D, An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, Dash, N, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dove, J, Dvořák, M, Dwyer, DA, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Jetter, S, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Koerner, LW, Kohn, S, Kramer, M, Langford, TJ, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, F, Li, HL, Li, QJ, Li, S, Li, SC, Li, SJ, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Lin, SK, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, Y, Liu, YH, Lu, C, and Lu, HQ
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Affordable and Clean Energy, Neutrino, Liquid scintillator, Energy calibration, Daya Bay, physics.ins-det, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Other Physical Sciences, Nuclear & Particles Physics, Nuclear and plasma physics
Abstract: A high precision calibration of the nonlinearity in the energy response of the Daya Bay Reactor Neutrino Experiment's antineutrino detectors is presented in detail. The energy nonlinearity originates from the particle-dependent light yield of the scintillator and charge-dependent electronics response. The nonlinearity model is constrained by γ calibration points from deployed and naturally occurring radioactive sources, the β spectrum from 12B decays, and a direct measurement of the electronics nonlinearity with a new flash analog-to-digital converter readout system. Less than 0.5% uncertainty in the energy nonlinearity calibration is achieved for positrons of kinetic energies greater than 1 MeV.
Published: 2019

10. Extraction of the U235 and Pu239 Antineutrino Spectra at Daya Bay

Author: Adey, D, An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, Dash, N, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dove, J, Dvořák, M, Dwyer, DA, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Koerner, LW, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, F, Li, HL, Li, QJ, Li, S, Li, SC, Li, SJ, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, Y, Liu, YH, Lu, C, Lu, HQ, Lu, JS, Luk, KB, and B., X
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Daya Bay Collaboration, hep-ex, physics.ins-det, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.
Published: 2019

11. Extraction of the ^{235}U and ^{239}Pu Antineutrino Spectra at Daya Bay.

Author: Adey, D, An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, Dash, N, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dove, J, Dvořák, M, Dwyer, DA, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Koerner, LW, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, F, Li, HL, Li, QJ, Li, S, Li, SC, Li, SJ, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, Y, Liu, YH, Lu, C, Lu, HQ, Lu, JS, Luk, KB, and Ma, XB
Subjects: Daya Bay Collaboration, hep-ex, physics.ins-det, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract: This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.
Published: 2019

12. Response to Comment on Daya Bay's definition and use of Delta(m^2_ee)

Author: Collaboration, The Day Bay, Adey, D, An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, Dash, N, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dove, J, Dvorak, M, Dwyer, DA, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Koerner, LW, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, F, Li, HL, Li, QJ, Li, S, Li, SC, Li, SJ, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Lin, SK, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Liu, Y, Liu, YH, Lu, C, Lu, HQ, and Lu, JS
Subjects: hep-ex
Abstract: The Daya Bay Collaboration responds to comments posted by S. Parke and R.Zukanovich Funchal regarding our use of Delta(m^2_ee).
Published: 2019

13. Study of the wave packet treatment of neutrino oscillation at Daya Bay

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Jones, D, Joshi, J, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, and Lin, S
Subjects: hep-ex, hep-ph, Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The disappearance of reactor $\bar{\nu}_e$ observed by the Daya Bayexperiment is examined in the framework of a model in which the neutrino isdescribed by a wave packet with a relative intrinsic momentum dispersion$\sigma_\text{rel}$. Three pairs of nuclear reactors and eight antineutrinodetectors, each with good energy resolution, distributed among threeexperimental halls, supply a high-statistics sample of $\bar{\nu}_e$ acquiredat nine different baselines. This provides a unique platform to test theeffects which arise from the wave packet treatment of neutrino oscillation. Themodified survival probability formula was used to fit Daya Bay data, providingthe first experimental limits: $2.38 \cdot 10^{-17} < \sigma_{\rm rel} < 0.23$.Treating the dimensions of the reactor cores and detectors as constraints, thelimits are improved: $10^{-14} \lesssim \sigma_{\rm rel} < 0.23$, and an upperlimit of $\sigma_{\rm rel}
Published: 2017

14. Measurement of electron antineutrino oscillation based on 1230 days of operation of the Daya Bay experiment

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Jones, D, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, and Li, ZB
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Affordable and Clean Energy, hep-ex, nucl-ex, physics.ins-det
Abstract: A measurement of electron antineutrino oscillation by the Daya Bay Reactor Neutrino Experiment is described in detail. Six 2.9-GWth nuclear power reactors of the Daya Bay and Ling Ao nuclear power facilities served as intense sources of νe's. Comparison of the νe rate and energy spectrum measured by antineutrino detectors far from the nuclear reactors (∼1500-1950 m) relative to detectors near the reactors (∼350-600 m) allowed a precise measurement of νe disappearance. More than 2.5 million νe inverse beta-decay interactions were observed, based on the combination of 217 days of operation of six antineutrino detectors (December, 2011-July, 2012) with a subsequent 1013 days using the complete configuration of eight detectors (October, 2012-July, 2015). The νe rate observed at the far detectors relative to the near detectors showed a significant deficit, R=0.949±0.002(stat)±0.002(syst). The energy dependence of νe disappearance showed the distinct variation predicted by neutrino oscillation. Analysis using an approximation for the three-flavor oscillation probability yielded the flavor-mixing angle sin22θ13=0.0841±0.0027(stat)±0.0019(syst) and the effective neutrino mass-squared difference of |Δmee2|=(2.50±0.06(stat)±0.06(syst))×10-3 eV2. Analysis using the exact three-flavor probability found Δm322=(2.45±0.06(stat)±0.06(syst))×10-3 eV2 assuming the normal neutrino mass hierarchy and Δm322=(-2.56±0.06(stat)±0.06(syst))×10-3 eV2 for the inverted hierarchy.
Published: 2017

15. Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Jones, D, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, and Liang, H
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, antineutrino flux, energy spectrum, reactor, Daya Bay, hep-ex, nucl-ex, physics.ins-det, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020 (0.992±0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4-6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.
Published: 2017

16. Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, and Liang, H
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Affordable and Clean Energy, Daya Bay Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3 eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2 eV^{2} region.
Published: 2016

17. Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Author: Adamson, P, An, FP, Anghel, I, Aurisano, A, Balantekin, AB, Band, HR, Barr, G, Bishai, M, Blake, A, Blyth, S, Bock, GJ, Bogert, D, Cao, D, Cao, GF, Cao, J, Cao, SV, Carroll, TJ, Castromonte, CM, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, R, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, J-H, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Childress, S, Chu, MC, Chukanov, A, Coelho, JAB, Corwin, L, Cronin-Hennessy, D, Cummings, JP, de Arcos, J, De Rijck, S, Deng, ZY, Devan, AV, Devenish, NE, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Escobar, CO, Evans, JJ, Falk, E, Feldman, GJ, Flanagan, W, Frohne, MV, Gabrielyan, M, Gallagher, HR, Germani, S, Gill, R, Gomes, RA, Gonchar, M, Gong, GH, Gong, H, Goodman, MC, Gouffon, P, Graf, N, Gran, R, Grassi, M, Grzelak, K, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Habig, A, Hackenburg, RW, Hahn, SR, Han, R, Hans, S, Hartnell, J, Hatcher, R, He, M, Heeger, KM, Heng, YK, Higuera, A, Holin, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, J, and Huang, XT
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Daya Bay Collaboration, MINOS Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}
Published: 2016

18. New measurement of θ13 via neutron capture on hydrogen at Daya Bay

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, JH, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, De Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, and Li, ZB
Subjects: hep-ex, physics.ins-det
Abstract: This article reports an improved independent measurement of neutrino mixing angle θ13 at the Daya Bay Reactor Neutrino Experiment. Electron antineutrinos were identified by inverse β-decays with the emitted neutron captured by hydrogen, yielding a data set with principally distinct uncertainties from that with neutrons captured by gadolinium. With the final two of eight antineutrino detectors installed, this study used 621 days of data including the previously reported 217-day data set with six detectors. The dominant statistical uncertainty was reduced by 49%. Intensive studies of the cosmogenic muon-induced Li9 and fast neutron backgrounds and the neutron-capture energy selection efficiency, resulted in a reduction of the systematic uncertainty by 26%. The deficit in the detected number of antineutrinos at the far detectors relative to the expected number based on the near detectors yielded sin22θ13=0.071±0.011 in the three-neutrino-oscillation framework. The combination of this result with the gadolinium-capture result is also reported.
Published: 2016

19. Measurement of cosmic-ray muons and muon-induced neutrons in the Aberdeen Tunnel Underground Laboratory

Author: Blyth, SC, Chan, YL, Chen, XC, Chu, MC, Cui, KX, Hahn, RL, Ho, TH, Hor, YK, Hsiung, YB, Hu, BZ, Kwan, KK, Kwok, MW, Kwok, T, Lau, YP, Lee, KP, Leung, JKC, Leung, KY, Lin, GL, Lin, YC, Luk, KB, Luk, WH, Ngai, HY, Ngai, WK, Ngan, SY, Pun, CSJ, Shih, K, Tam, YH, Tsang, RHM, Wang, CH, Wong, CM, Wong, HHC, Wong, HLH, Wong, KK, and Yeh, M
Subjects: Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, physics.ins-det, hep-ex, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Astronomical sciences, Particle and high energy physics
Abstract: We have measured the muon flux and production rate of muon-induced neutrons at a depth of 611 m water equivalent. Our apparatus comprises three layers of crossed plastic scintillator hodoscopes for tracking the incident cosmic-ray muons and 760 L of a gadolinium-doped liquid scintillator for producing and detecting neutrons. The vertical muon intensity was measured to be Iμ=(5.7±0.6)×10-6 cm-2 s-1 sr-1. The yield of muon-induced neutrons in the liquid scintillator was determined to be Yn=(1.19±0.08(stat)±0.21(syst))×10-4 neutrons/(μ·g·cm-2). A fit to the recently measured neutron yields at different depths gave a mean muon energy dependence of 0.76±0.03 for liquid-scintillator targets.
Published: 2016

20. The detector system of the Daya Bay reactor neutrino experiment

Author: An, FP, Bai, JZ, Balantekin, AB, Band, HR, Beavis, D, Beriguete, W, Bishai, M, Blyth, S, Brown, RL, Butorov, I, Cao, D, Cao, GF, Cao, J, Carr, R, Cen, WR, Chan, WT, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chasman, C, Chen, HY, Chen, HS, Chen, MJ, Chen, QY, Chen, SJ, Chen, SM, Chen, XC, Chen, XH, Chen, XS, Chen, YX, Chen, Y, Cheng, JH, Cheng, J, Cheng, YP, Cherwinka, JJ, Chidzik, S, Chow, K, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dong, L, Dove, J, Draeger, E, Du, XF, Dwyer, DA, Edwards, WR, Ely, SR, Fang, SD, Fu, JY, Fu, ZW, Ge, LQ, Ghazikhanian, V, Gill, R, Goett, J, Gonchar, M, Gong, GH, Gong, H, Gornushkin, YA, Grassi, M, Greenler, LS, Gu, WQ, Guan, MY, Guo, RP, Guo, XH, Hackenburg, RW, Hahn, RL, Han, R, Hans, S, He, M, He, Q, He, WS, Heeger, KM, Heng, YK, Higuera, A, Hinrichs, P, Ho, TH, Hoff, M, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, HZ, Huang, HX, Huang, PW, Huang, X, Huang, XT, Huber, P, Hussain, G, Isvan, Z, Jaffe, DE, and Jaffke, P
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Neutrino oscillation, Neutrino mixing, Reactor, Daya Bay, physics.ins-det, hep-ex, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Other Physical Sciences, Nuclear & Particles Physics, Nuclear and plasma physics
Abstract: The Daya Bay experiment was the first to report simultaneous measurements of reactor antineutrinos at multiple baselines leading to the discovery of ν¯e oscillations over km-baselines. Subsequent data has provided the world's most precise measurement of sin22θ13 and the effective mass splitting Δmee2. The experiment is located in Daya Bay, China where the cluster of six nuclear reactors is among the world's most prolific sources of electron antineutrinos. Multiple antineutrino detectors are deployed in three underground water pools at different distances from the reactor cores to search for deviations in the antineutrino rate and energy spectrum due to neutrino mixing. Instrumented with photomultiplier tubes, the water pools serve as shielding against natural radioactivity from the surrounding rock and provide efficient muon tagging. Arrays of resistive plate chambers over the top of each pool provide additional muon detection. The antineutrino detectors were specifically designed for measurements of the antineutrino flux with minimal systematic uncertainty. Relative detector efficiencies between the near and far detectors are known to better than 0.2%. With the unblinding of the final two detectors' baselines and target masses, a complete description and comparison of the eight antineutrino detectors can now be presented. This paper describes the Daya Bay detector systems, consisting of eight antineutrino detectors in three instrumented water pools in three underground halls, and their operation through the first year of eight detector data-taking.
Published: 2016

21. Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Butorov, I, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, JH, Cheng, J, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dove, J, Draeger, E, Dwyer, DA, Edwards, WR, Ely, SR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, XH, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, KY, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, Li, QJ, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, and Lin, GL
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Daya Bay Collaboration, hep-ex, nucl-ex, physics.ins-det, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract: This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18) cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43) cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.
Published: 2016

22. New Measurement of Antineutrino Oscillation with the Full Detector Configuration at Daya Bay

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Butorov, I, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, JH, Cheng, J, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Draeger, E, Dwyer, DA, Edwards, WR, Ely, SR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, XH, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, KY, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, Li, QJ, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, PY, Lin, SK, and Ling, JJ
Subjects: Daya Bay Collaboration, hep-ex, nucl-ex, physics.ins-det, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract: We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th} ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3} eV^{2} in the three-neutrino framework.
Published: 2015

23. Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

Author: Daya Bay Collaboration, An, F. P., Balantekin, A. B., Band, H. R., Beriguete, W., Bishai, M., Blyth, S., Brown, R. L., Butorov, I., Cao, G. F., Cao, J., Carr, R., Chan, Y. L., Chang, J. F., Chang, Y., Chasman, C., Chen, H. S., Chen, H. Y., Chen, S. J., Chen, S. M., Chen, X. C., Chen, X. H., Chen, Y., Chen, Y. X., Cheng, Y. P., Cherwinka, J. J., Chu, M. C., Cummings, J. P., de Arcos, J., Deng, Z. Y., Ding, Y. Y., Diwan, M. V., Draeger, E., Du, X. F., Dwyer, D. A., Edwards, W. R., Ely, S. R., Fu, J. Y., Ge, L. Q., Gill, R., Gonchar, M., Gong, G. H., Gong, H., Gornushkin, Y. A., Gu, W. Q., Guan, M. Y., Guo, X. H., Hackenburg, R. W., Hahn, R. L., Han, G. H., Hans, S., He, M., Heeger, K. M., Heng, Y. K., Hinrichs, P., Hor, yk., Hsiung, Y. B., Hu, B. Z., Hu, L. J., Hu, L. M., Hu, T., Hu, W., Huang, E. C., Huang, H. X., Huang, H. Z., Huang, X. T., Huber, P., Hussain, G., Isvan, Z., Jaffe, D. E., Jaffke, P., Jetter, S., Ji, X. L., Ji, X. P., Jiang, H. J., Jiao, J. B., Johnson, R. A., Kang, L., Kettell, S. H., Kramer, M., Kwan, K. K., Kwok, M. W., Kwok, T., Lai, W. C., Lai, W. H., Lau, K., Lebanowski, L., Lee, J., Lei, R. T., Leitner, R., Leung, A., Leung, J. K. C., Lewis, C. A., Li, D. J., Li, F., Li, G. S., Li, Q. J., Li, W. D., Li, X. N., Li, X. Q., Li, Y. F., Li, Z. B., Liang, H., Lin, C. J., Lin, G. L., Lin, S. K., Lin, Y. C., Ling, J. J., Link, J. M., Littenberg, L., Littlejohn, B. R., Liu, D. W., Liu, H., Liu, J. C., Liu, J. L., Liu, S. S., Liu, Y. B., Lu, C., Lu, H. Q., Luk, K. B., Ma, Q. M., Ma, X. B., Ma, X. Y., Ma, Y. Q., McDonald, K. T., McFarlane, M. C., McKeown, R. D., Meng, Y., Mitchell, I., Nakajima, Y., Napolitano, J., Naumov, D., Naumova, E., Nemchenok, I., Ngai, H. Y., Ngai, W. K., Ning, Z., Ochoa-Ricoux, J. P., Olshevski, A., Patton, S., Pec, V., Peng, J. C., Piilonen, L. E., Pinsky, L., Pun, C. S. J., Qi, F. Z., Qi, M., Qian, X., Raper, N., Ren, B., Ren, J., Rosero, R., Roskovec, B., Ruan, X. C., Shao, B. B., Steiner, H., Sun, G. X., Sun, J. L., Tam, Y. H., Tanaka, H. K., Tang, X., Themann, H., Trentalange, S., Tsai, O., Tsang, K. V., Tsang, R. H. M., Tull, C. E., Tung, Y. C., Viren, B., Vorobel, V., Wang, C. H., Wang, L. S., Wang, L. Y., Wang, L. Z., Wang, M., Wang, N. Y., Wang, R. G., Wang, W., Wang, W. W., Wang, X., Wang, Y. F., Wang, Z., Wang, Z. M., Webber, D. M., Wei, H., Wei, Y. D., Wen, L. J., Whisnant, K., White, C. G., Whitehead, L., Wise, T., Wong, H. L. H., Wong, S. C. F., Worcester, E., Wu, Q., Xia, D. M., Xia, J. K., Xia, X., Xing, Z. Z., Xu, J., Xu, J. L., Xu, J. Y., Xu, Y., Xue, T., Yan, J., Yang, C. G., Yang, L., Yang, M. S., Ye, M., Yeh, M., Yeh, Y. S., Young, B. L., Yu, G. Y., Yu, J. Y., Yu, Z. Y., Zang, S. L., Zhan, L., Zhang, C., Zhang, F. H., Zhang, J. W., Zhang, Q. M., Zhang, S. H., Zhang, Y. C., Zhang, Y. H., Zhang, Y. M., Zhang, Y. X., Zhang, Z. J., Zhang, Z. P., Zhang, Z. Y., Zhao, J., Zhao, Q. W., Zhao, Y. B., Zheng, L., Zhong, W. L., Zhou, L., Zhou, Z. Y., Zhuang, H. L., and Zou, J. H.
Subjects: High Energy Physics - Experiment, Nuclear Experiment
Abstract: A measurement of the energy dependence of antineutrino disappearance at the Daya Bay Reactor Neutrino Experiment is reported. Electron antineutrinos ($\overline{\nu}_{e}$) from six $2.9$ GW$_{\rm th}$ reactors were detected with six detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41589 (203809 and 92912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude $\sin^{2}2\theta_{13} = 0.090^{+0.008}_{-0.009} $ and the first direct measurement of the $\overline{\nu}_{e}$ mass-squared difference $|\Delta m^{2}_{ee}|= (2.59_{-0.20}^{+0.19}) \times 10^{-3}\ {\rm eV}^2 $ is obtained using the observed $\overline{\nu}_{e}$ rates and energy spectra in a three-neutrino framework. This value of $|\Delta m^{2}_{ee}|$ is consistent with $|\Delta m^{2}_{\mu\mu}|$ measured by muon neutrino disappearance, supporting the three-flavor oscillation model., Comment: As accepted for publication by Phys. Rev. Lett. including ancillary table
Published: 2013
Full Text: View/download PDF

24. The muon system of the Daya Bay Reactor antineutrino experiment

Author: An, FP, Balantekin, AB, Band, HR, Beriguete, W, Bishai, M, Blyth, S, Brown, RE, Butorov, I, Cao, GF, Cao, J, Carr, R, Chan, YL, Chang, JF, Chang, L, Chang, Y, Chasman, C, Chen, HS, Chen, HY, Chen, QY, Chen, SJ, Chen, SM, Chen, XC, Chen, XH, Chen, Y, Chen, YX, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, Dale, E, De Arcos, J, Deng, ZY, Ding, YY, Diwan, MV, Draeger, E, Du, XF, Dwyer, DA, Edwards, WR, Ely, SR, Fu, JY, Ge, LQ, Gill, R, Goett, J, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guan, MY, Guo, XH, Hackenburg, RW, Han, GH, Hans, S, He, M, He, Q, Heeger, KM, Heng, YK, Hinrichs, P, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LJ, Hu, LM, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, HZ, Huang, XT, Huber, P, Hussain, G, Isvan, Z, Jaffe, DE, Jaffke, P, Jetter, S, Ji, XL, Ji, XP, Jiang, HJ, Jiao, JB, Johnson, RA, Kang, L, Kebwaro, JM, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Lai, WC, Lai, WH, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, A, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, and Li, QJ
Subjects: Neutrinos, Water shield, Cosmic ray, Muons, Underground, Nuclear & Particles Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Other Physical Sciences
Abstract: The Daya Bay experiment consists of functionally identical antineutrino detectors immersed in pools of ultrapure water in three well-separated underground experimental halls near two nuclear reactor complexes. These pools serve both as shields against natural, low-energy radiation, and as water Cherenkov detectors that efficiently detect cosmic muons using arrays of photomultiplier tubes. Each pool is covered by a plane of resistive plate chambers as an additional means of detecting muons. Design, construction, operation, and performance of these muon detectors are described.
Published: 2015

25. Independent measurement of the neutrino mixing angle theta(13) via neutron capture on hydrogen at Daya Bay

Author: An, FP, Balantekin, AB, Band, HR, Beriguete, W, Bishai, M, Blyth, S, Butorov, I, Cao, GF, Cao, J, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chasman, C, Chen, H, Chen, QY, Chen, SM, Chen, X, Chen, YX, Chen, Y, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, YY, Diwan, MV, Draeger, E, Du, XF, Dwyer, DA, Edwards, WR, Ely, SR, Fu, JY, Ge, LQ, Gill, R, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guan, MY, Guo, XH, Hackenburg, RW, Han, GH, Hans, S, He, M, Heeger, M, Heng, YK, Hinrichs, P, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, H, Huang, XT, Huber, P, Hussain, G, Isvan, Z, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiang, HJ, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Lai, WC, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, A, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, Li, QJ, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, and Lin, PY
Subjects: hep-ex, physics.ins-det, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: A new measurement of the $\theta_{13}$ mixing angle has been obtained at theDaya Bay Reactor Neutrino Experiment via the detection of inverse beta decaystagged by neutron capture on hydrogen. The antineutrino events for hydrogencapture are distinct from those for gadolinium capture with largely differentsystematic uncertainties, allowing a determination independent of thegadolinium-capture result and an improvement on the precision of $\theta_{13}$measurement. With a 217-day antineutrino data set obtained with sixantineutrino detectors and from six 2.9 GW$_{th}$ reactors, the rate deficitobserved at the far hall is interpreted as $\sin^22\theta_{13}=0.083\pm0.018$in the three-flavor oscillation model. When combined with thegadolinium-capture result from Daya Bay, we obtain$\sin^22\theta_{13}=0.089\pm0.008$ as the final result for thesix-antineutrino-detector configuration of the Daya Bay experiment.
Published: 2014

26. Independent measurement of the neutrino mixing angle θ13 via neutron capture on hydrogen at Daya Bay

Author: An, FP, Balantekin, AB, Band, HR, Beriguete, W, Bishai, M, Blyth, S, Butorov, I, Cao, GF, Cao, J, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chasman, C, Chen, H, Chen, QY, Chen, SM, Chen, X, Chen, YX, Chen, Y, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, YY, Diwan, MV, Draeger, E, Du, XF, Dwyer, DA, Edwards, WR, Ely, SR, Fu, JY, Ge, LQ, Gill, R, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guan, MY, Guo, XH, Hackenburg, RW, Han, GH, Hans, S, He, M, Heeger, KM, Heng, YK, Hinrichs, P, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, H, Huang, XT, Huber, P, Hussain, G, Isvan, Z, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiang, HJ, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Lai, WC, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, A, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, Li, QJ, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, and Lin, PY
Subjects: hep-ex, physics.ins-det, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: A new measurement of the $\theta_{13}$ mixing angle has been obtained at theDaya Bay Reactor Neutrino Experiment via the detection of inverse beta decaystagged by neutron capture on hydrogen. The antineutrino events for hydrogencapture are distinct from those for gadolinium capture with largely differentsystematic uncertainties, allowing a determination independent of thegadolinium-capture result and an improvement on the precision of $\theta_{13}$measurement. With a 217-day antineutrino data set obtained with sixantineutrino detectors and from six 2.9 GW$_{th}$ reactors, the rate deficitobserved at the far hall is interpreted as $\sin^22\theta_{13}=0.083\pm0.018$in the three-flavor oscillation model. When combined with thegadolinium-capture result from Daya Bay, we obtain$\sin^22\theta_{13}=0.089\pm0.008$ as the final result for thesix-antineutrino-detector configuration of the Daya Bay experiment.
Published: 2014

27. Search for a light sterile neutrino at Daya Bay.

Author: An, FP, Balantekin, AB, Band, HR, Beriguete, W, Bishai, M, Blyth, S, Butorov, I, Cao, GF, Cao, J, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chasman, C, Chen, H, Chen, QY, Chen, SM, Chen, X, Chen, YX, Chen, Y, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, YY, Diwan, MV, Draeger, E, Du, XF, Dwyer, DA, Edwards, WR, Ely, SR, Fu, JY, Ge, LQ, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, XH, Hackenburg, RW, Han, GH, Hans, S, He, M, Heeger, KM, Heng, YK, Hinrichs, P, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, H, Huang, XT, Huber, P, Hussain, G, Isvan, Z, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiang, HJ, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Lai, WC, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, A, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, Li, QJ, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, and Lin, GL
Subjects: Daya Bay Collaboration, hep-ex, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract: A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)
Published: 2014

28. Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay.

Author: An, FP, Balantekin, AB, Band, HR, Beriguete, W, Bishai, M, Blyth, S, Brown, RL, Butorov, I, Cao, GF, Cao, J, Carr, R, Chan, YL, Chang, JF, Chang, Y, Chasman, C, Chen, HS, Chen, HY, Chen, SJ, Chen, SM, Chen, XC, Chen, XH, Chen, Y, Chen, YX, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, YY, Diwan, MV, Draeger, E, Du, XF, Dwyer, DA, Edwards, WR, Ely, SR, Fu, JY, Ge, LQ, Gill, R, Gonchar, M, Gong, GH, Gong, H, Gornushkin, YA, Gu, WQ, Guan, MY, Guo, XH, Hackenburg, RW, Hahn, RL, Han, GH, Hans, S, He, M, Heeger, KM, Heng, YK, Hinrichs, P, Hor, Yk, Hsiung, YB, Hu, BZ, Hu, LJ, Hu, LM, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, HZ, Huang, XT, Huber, P, Hussain, G, Isvan, Z, Jaffe, DE, Jaffke, P, Jetter, S, Ji, XL, Ji, XP, Jiang, HJ, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Lai, WC, Lai, WH, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, A, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, Li, QJ, Li, WD, Li, XN, Li, XQ, and Li, YF
Subjects: Daya Bay Collaboration, hep-ex, nucl-ex, General Physics, Mathematical Sciences, Physical Sciences, Engineering
Abstract: A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9 GW(th) reactors were detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3) eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.
Published: 2014

29. Results from the Daya Bay Reactor Neutrino Experiment

Author: Tsang, KV, An, FP, An, Q, Bai, JZ, Balantekin, AB, Band, HR, Beriguete, W, Bishai, M, Blyth, S, Brown, RL, Cao, GF, Cao, J, Carr, R, Chan, WT, Chang, JF, Chang, Y, Chasman, C, Chen, HS, Chen, HY, Chen, SJ, Chen, SM, Chen, XC, Chen, XH, Chen, XS, Chen, Y, Chen, YX, Cherwinka, JJ, Chu, MC, Cummings, JP, Deng, ZY, Ding, YY, Diwan, MV, Draeger, E, Du, XF, Dwyer, D, Edwards, WR, Ely, SR, Fang, SD, Fu, JY, Fu, ZW, Ge, LQ, Gill, RL, Gonchar, M, Gong, GH, Gong, H, Gornushkin, YA, Gu, WQ, Guan, MY, Guo, XH, Hackenburg, RW, Hahn, RL, Hans, S, Hao, HF, He, M, He, Q, Heeger, KM, Heng, YK, Hinrichs, P, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Huang, HX, Huang, HZ, Huang, XT, Huber, P, Issakov, V, Isvan, Z, Jaffe, DE, Jetter, S, Ji, XL, Ji, XP, Jiang, HJ, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Lai, CY, Lai, WC, Lai, WH, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, JKC, Leung, KY, Lewis, CA, Li, F, Li, GS, Li, QJ, Li, WD, Li, XB, Li, XN, Li, XQ, and Li, Y
Subjects: Neutrino Oscillation, Neutrino Mixing, Reactor, Daya Bay
Abstract: The Daya Bay Reactor Neutrino Experiment was designed to achieve a sensitivity on the value of sin22θ13 to better than 0.01 at 90% CL. The experiment consists of eight antineutrino detectors installed underground at different baselines from six nuclear reactors. With data collected with six antineutrino detectors for 55 days, Daya Bay announced the discovery of a non-zero value for sin22θ13 with a significance of 5.2 standard deviations in March 2012. The most recent analysis with 139 days of data acquired in a six-detector configuration yields sin22θ13=0.089±0.010(stat.)±0.005(syst.), which is the most precise measurement of sin22θ13 to date. © 2013.
Published: 2014

30. Improved measurement of electron antineutrino disappearance at Daya Bay

Author: An, FP, An, Q, Bai, JZ, Balantekin, AB, Band, HR, Beriguete, W, Bishai, M, Blyth, S, Brown, RL, Cao, GF, Cao, J, Carr, R, Chan, WT, Chang, JF, Chang, Y, Chasman, C, Chen, HS, Chen, HY, Chen, SJ, Chen, SM, Chen, XC, Chen, XH, Chen, XS, Chen, Y, Chen, YX, Cherwinka, JJ, Chu, MC, Cummings, JP, Deng, ZY, Ding, YY, Diwan, MV, Draeger, E, Du, XF, Dwyer, D, Edwards, WR, Ely, SR, Fang, SD, Fu, JY, Fu, ZW, Ge, LQ, Gill, RL, Gonchar, M, Gong, GH, Gong, H, Gornushkin, YA, Gu, WQ, Guan, MY, Guo, XH, Hackenburg, RW, Hahn, RL, Hans, S, Hao, HF, He, M, He, Q, Heeger, KM, Heng, YK, Hinrichs, P, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Huang, HX, Huang, HZ, Huang, XT, Huber, P, Issakov, V, Isvan, Z, Jaffe, DE, Jetter, S, Ji, XL, Ji, XP, Jiang, HJ, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Lai, CY, Lai, WC, Lai, WH, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, JKC, Leung, KY, Lewis, CA, Li, F, Li, GS, Li, QJ, Li, WD, Li, XB, Li, XN, Li, XQ, Li, Y, and Li, ZB
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, neutrino oscillation, neutrino mixing, reactor, Daya Bay, hep-ex, nucl-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: We report an improved measurement of the neutrino mixing angle θ13 from the Daya Bay Reactor Neutrino Experiment. We exclude a zero value for sin22θ13 with a significance of 7.7 standard deviations. Electron antineutrinos from six reactors of 2.9 GW th were detected in six antineutrino detectors deployed in two near (flux-weighted baselines of 470 m and 576 m) and one far (1648 m) underground experimental halls. Using 139 days of data, 28909 (205308) electron antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to the expected number of antineutrinos assuming no oscillations at the far hall is 0.944±0.007(stat.)±0.003(syst.). An analysis of the relative rates in six detectors finds sin22θ13=0. 089±0.010(stat.)±0.005(syst.) in a three-neutrino framework. © 2013 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
Published: 2013

31. Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT.

Author: An, FP, An, FP, Andriamirado, M, Balantekin, AB, Band, HR, Bass, CD, Bergeron, DE, Berish, D, Bishai, M, Blyth, S, Bowden, NS, Bryan, CD, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Classen, T, Conant, AJ, Cummings, JP, Dalager, O, Deichert, G, Delgado, A, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dolinski, MJ, Dolzhikov, D, Dove, J, Dvořák, M, Dwyer, DA, Erickson, A, Foust, BT, Gaison, JK, Galindo-Uribarri, A, Gallo, JP, Gilbert, CE, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, Hansell, AB, He, M, Heeger, KM, Heffron, B, Heng, YK, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, JH, Huang, XT, Huang, YB, Huber, P, Koblanski, J, Jaffe, DE, Jayakumar, S, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, DC, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kyzylova, O, Lane, CE, Langford, TJ, LaRosa, J, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, HL, Li, JJ, Li, QJ, Li, RH, Li, S, Li, SC, An, FP, An, FP, Andriamirado, M, Balantekin, AB, Band, HR, Bass, CD, Bergeron, DE, Berish, D, Bishai, M, Blyth, S, Bowden, NS, Bryan, CD, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Classen, T, Conant, AJ, Cummings, JP, Dalager, O, Deichert, G, Delgado, A, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dolinski, MJ, Dolzhikov, D, Dove, J, Dvořák, M, Dwyer, DA, Erickson, A, Foust, BT, Gaison, JK, Galindo-Uribarri, A, Gallo, JP, Gilbert, CE, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, Hansell, AB, He, M, Heeger, KM, Heffron, B, Heng, YK, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, JH, Huang, XT, Huang, YB, Huber, P, Koblanski, J, Jaffe, DE, Jayakumar, S, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, DC, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kyzylova, O, Lane, CE, Langford, TJ, LaRosa, J, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, HL, Li, JJ, Li, QJ, Li, RH, Li, S, and Li, SC
Abstract: A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.
Published: 2022

32. Search for electron-antineutrinos associated with gravitational-wave events GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817 at Daya Bay * *Daya Bay is supported in part by the Ministry of Science and Technology of China, the U.S. Department of Energy, the Chinese Academy of Sciences, the CAS Center for Excellence in Particle Physics, the National Natural Science Foundation of China, the Guangdong provincial government, the Shenzhen municipal government, the China General Nuclear Power Group, Key Laboratory of Particle and Radiation Imaging (Tsinghua University), the Ministry of Education, Key Laboratory of Particle Physics and Particle Irradiation (Shandong University), the Ministry of Education, Shanghai Laboratory for Particle Physics and Cosmology, the Research Grants Council of the Hong Kong Special Administrative Region of China, the University Development Fund of the University of Hong Kong, the MOE program for Research of Excellence at National Taiwan University, National Chia

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, GF, Cao, J, Chang, JF, Chang, Y, Chen, HS, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, ZK, Cherwinka, JJ, Chu, MC, Cummings, JP, Dalager, O, Deng, FS, Ding, YY, Diwan, MV, Dohnal, T, Dove, J, Dvořák, M, Dwyer, DA, Gallo, JP, Gonchar, M, Gong, GH, Gong, H, Gu, WQ, Guo, JY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, JR, Hu, T, Hu, ZJ, Huang, HX, Huang, XT, Huang, YB, Huber, P, Jaffe, DE, Jen, KL, Ji, XL, Ji, XP, Johnson, RA, Jones, D, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Langford, TJ, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, F, Li, JJ, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, S, Ling, JJ, Link, JM, Littenberg, L, Littlejohn, BR, Liu, JC, Liu, JL, Lu, C, Lu, HQ, Lu, JS, Luk, KB, B., X, Y., X, Q., Y, Marshall, C, Caicedo, DA Martinez, McDonald, KT, McKeown, RD, and Meng, Y
Subjects: astro-ph.HE, Particle and Plasma Physics, gravitational waves, hep-ex, fluence, Molecular, Nuclear, electron-antineutrinos, upper limit, physics.ins-det, Atomic, Nuclear & Particles Physics
Abstract: The establishment of a possible connection between neutrino emission and gravitational-wave (GW) bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge. In the Daya Bay experiment, using the data collected from December 2011 to August 2017, a search was performed for electron-Antineutrino signals that coincided with detected GW events, including GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817. We used three time windows of 10, 500, and 1000 s relative to the occurrence of the GW events and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates. The detected electron-Antineutrino candidates were consistent with the expected background rates for all the three time windows. Assuming monochromatic spectra, we found upper limits (90% confidence level) of the electron-Antineutrino fluence of (1.13-2.44)×1011 cm-2 at 5 MeV to 8.0×107 cm-2 at 100 MeV for the three time windows. Under the assumption of a Fermi-Dirac spectrum, the upper limits were found to be (5.4-7.0)×109 cm-2 for the three time windows.
Published: 2021

33. Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay**Supported in part by the Ministry of Science and Technology of China, the United States Department of Energy, the Chinese Academy of Sciences, the CAS Center for Excellence in Particle Physics, the National Natural Science Foundation of China, the Guangdong provincial government, the Shenzhen municipal government, the China General Nuclear Power Group, the Research Grants Council of the Hong Kong Special Administrative Region of China, the MOST and MOE in Taiwan, the U.S. National Science Foundation, the Ministry of Education, Youth and Sports of the Czech Republic, the Joint Institute of Nuclear Research in Dubna, Russia, the NSFC-RFBR joint research program, the National Commission for Scientific and Technological Research of Chile

Author: An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Jones, D, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, and Liang, H
Subjects: Particle and Plasma Physics, hep-ex, Daya Bay, energy spectrum, Molecular, Nuclear, antineutrino flux, nucl-ex, physics.ins-det, Atomic, Nuclear & Particles Physics, reactor
Abstract: A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020 (0.992±0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4-6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.
Published: 2017

34. Measurement of Electron Antineutrino Oscillation Amplitude and Frequency via Neutron Capture on Hydrogen at Daya Bay.

Author: An FP, Bai WD, Balantekin AB, Bishai M, Blyth S, Cao GF, Cao J, Chang JF, Chang Y, Chen HS, Chen HY, Chen SM, Chen Y, Chen YX, Chen ZY, Cheng J, Cheng J, Cheng YC, Cheng ZK, Cherwinka JJ, Chu MC, Cummings JP, Dalager O, Deng FS, Ding XY, Ding YY, Diwan MV, Dohnal T, Dolzhikov D, Dove J, Dugas KV, Duyang HY, Dwyer DA, Gallo JP, Gonchar M, Gong GH, Gong H, Gu WQ, Guo JY, Guo L, Guo XH, Guo YH, Guo Z, Hackenburg RW, Han Y, Hans S, He M, Heeger KM, Heng YK, Hor YK, Hsiung YB, Hu BZ, Hu JR, Hu T, Hu ZJ, Huang HX, Huang JH, Huang XT, Huang YB, Huber P, Jaffe DE, Jen KL, Ji XL, Ji XP, Johnson RA, Jones D, Kang L, Kettell SH, Kohn S, Kramer M, Langford TJ, Lee J, Lee JHC, Lei RT, Leitner R, Leung JKC, Li F, Li HL, Li JJ, Li QJ, Li RH, Li S, Li SC, Li WD, Li XN, Li XQ, Li YF, Li ZB, Liang H, Lin CJ, Lin GL, Lin S, Ling JJ, Link JM, Littenberg L, Littlejohn BR, Liu JC, Liu JL, Liu JX, Lu C, Lu HQ, Luk KB, Ma BZ, Ma XB, Ma XY, Ma YQ, Mandujano RC, Marshall C, McDonald KT, McKeown RD, Meng Y, Napolitano J, Naumov D, Naumova E, Nguyen TMT, Ochoa-Ricoux JP, Olshevskiy A, Park J, Patton S, Peng JC, Pun CSJ, Qi FZ, Qi M, Qian X, Raper N, Ren J, Morales Reveco C, Rosero R, Roskovec B, Ruan XC, Russell B, Steiner H, Sun JL, Tmej T, Treskov K, Tse WH, Tull CE, Tung YC, Viren B, Vorobel V, Wang CH, Wang J, Wang M, Wang NY, Wang RG, Wang W, Wang X, Wang YF, Wang Z, Wang Z, Wang ZM, Wei HY, Wei LH, Wei W, Wen LJ, Whisnant K, White CG, Wong HLH, Worcester E, Wu DR, Wu Q, Wu WJ, Xia DM, Xie ZQ, Xing ZZ, Xu HK, Xu JL, Xu T, Xue T, Yang CG, Yang L, Yang YZ, Yao HF, Ye M, Yeh M, Young BL, Yu HZ, Yu ZY, Yue BB, Zavadskyi V, Zeng S, Zeng Y, Zhan L, Zhang C, Zhang FY, Zhang HH, Zhang JL, Zhang JW, Zhang QM, Zhang SQ, Zhang XT, Zhang YM, Zhang YX, Zhang YY, Zhang ZJ, Zhang ZP, Zhang ZY, Zhao J, Zhao RZ, Zhou L, Zhuang HL, and Zou JH
Abstract: This Letter reports the first measurement of the oscillation amplitude and frequency of reactor antineutrinos at Daya Bay via neutron capture on hydrogen using 1958 days of data. With over 3.6 million signal candidates, an optimized candidate selection, improved treatment of backgrounds and efficiencies, refined energy calibration, and an energy response model for the capture-on-hydrogen sensitive region, the relative ν[over ¯]_{e} rates and energy spectra variation among the near and far detectors gives sin^{2}2θ_{13}=0.0759_{-0.0049}^{+0.0050} and Δm_{32}^{2}=(2.72_{-0.15}^{+0.14})×10^{-3} eV^{2} assuming the normal neutrino mass ordering, and Δm_{32}^{2}=(-2.83_{-0.14}^{+0.15})×10^{-3} eV^{2} for the inverted neutrino mass ordering. This estimate of sin^{2}2θ_{13} is consistent with and essentially independent from the one obtained using the capture-on-gadolinium sample at Daya Bay. The combination of these two results yields sin^{2}2θ_{13}=0.0833±0.0022, which represents an 8% relative improvement in precision regarding the Daya Bay full 3158-day capture-on-gadolinium result.
Published: 2024
Full Text: View/download PDF

35. Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A.

Author: Cao Z, Aharonian F, Axikegu, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Bian W, Bukevich AV, Cao Q, Cao WY, Cao Z, Chang J, Chang JF, Chen AM, Chen ES, Chen HX, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen S, Chen SH, Chen SZ, Chen TL, Chen Y, Cheng N, Cheng YD, Cui MY, Cui SW, Cui XH, Cui YD, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Dong XQ, Duan KK, Fan JH, Fan YZ, Fang J, Fang JH, Fang K, Feng CF, Feng H, Feng L, Feng SH, Feng XT, Feng Y, Feng YL, Gabici S, Gao B, Gao CD, Gao Q, Gao W, Gao WK, Ge MM, Geng LS, Giacinti G, Gong GH, Gou QB, Gu MH, Guo FL, Guo XL, Guo YQ, Guo YY, Han YA, Hasan M, He HH, He HN, He JY, He Y, Hor YK, Hou BW, Hou C, Hou X, Hu HB, Hu Q, Hu SC, Huang DH, Huang TQ, Huang WJ, Huang XT, Huang XY, Huang Y, Ji XL, Jia HY, Jia K, Jiang K, Jiang XW, Jiang ZJ, Jin M, Kang MM, Karpikov I, Kuleshov D, Kurinov K, Li BB, Li CM, Li C, Li C, Li D, Li F, Li HB, Li HC, Li J, Li J, Li K, Li SD, Li WL, Li WL, Li XR, Li X, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu DB, Liu H, Liu HD, Liu J, Liu JL, Liu MY, Liu RY, Liu SM, Liu W, Liu Y, Liu YN, Luo Q, Luo Y, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Min Z, Mitthumsiri W, Mu HJ, Nan YC, Neronov A, Ou LJ, Pattarakijwanich P, Pei ZY, Qi JC, Qi MY, Qiao BQ, Qin JJ, Raza A, Ruffolo D, Sáiz A, Saeed M, Semikoz D, Shao L, Shchegolev O, Sheng XD, Shu FW, Song HC, Stenkin YV, Stepanov V, Su Y, Sun DX, Sun QN, Sun XN, Sun ZB, Takata J, Tam PHT, Tang QW, Tang R, Tang ZB, Tian WW, Wang C, Wang CB, Wang GW, Wang HG, Wang HH, Wang JC, Wang K, Wang K, Wang LP, Wang LY, Wang PH, Wang R, Wang W, Wang XG, Wang XY, Wang Y, Wang YD, Wang YJ, Wang ZH, Wang ZX, Wang Z, Wang Z, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu QW, Wu S, Wu XF, Wu YS, Xi SQ, Xia J, Xiang GM, Xiao DX, Xiao G, Xin YL, Xing Y, Xiong DR, Xiong Z, Xu DL, Xu RF, Xu RX, Xu WL, Xue L, Yan DH, Yan JZ, Yan T, Yang CW, Yang CY, Yang F, Yang FF, Yang LL, Yang MJ, Yang RZ, Yang WX, Yao YH, Yao ZG, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Yue H, Zeng HD, Zeng TX, Zeng W, Zha M, Zhang BB, Zhang F, Zhang H, Zhang HM, Zhang HY, Zhang JL, Zhang L, Zhang PF, Zhang PP, Zhang R, Zhang SB, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang YF, Zhang Y, Zhang Y, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zhao XH, Zheng F, Zhong WJ, Zhou B, Zhou H, Zhou JN, Zhou M, Zhou P, Zhou R, Zhou XX, Zhou XX, Zhu BY, Zhu CG, Zhu FR, Zhu H, Zhu KJ, Zou YC, and Zuo X
Abstract: On 9 October 2022, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time gamma-ray burst 221009A, recording the highest photon statistics in the TeV band ever obtained from a gamma-ray burst. We use this unique observation to place stringent constraints on the energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are E_{QG,1}>10 times the Planck energy E_{Pl} for the linear LIV effect, and E_{QG,2}>6×10^{-8}E_{Pl} for the quadratic LIV effect. Our limits on the quadratic LIV case improve previous best bounds by factors of 5-7.
Published: 2024
Full Text: View/download PDF

36. Constraints on Ultraheavy Dark Matter Properties from Dwarf Spheroidal Galaxies with LHAASO Observations.

Author: Cao Z, Aharonian F, An Q, Axikegu, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Cai JT, Cao Q, Cao WY, Cao Z, Chang J, Chang JF, Chen AM, Chen ES, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen SH, Chen SZ, Chen TL, Chen Y, Cheng N, Cheng YD, Cui MY, Cui SW, Cui XH, Cui YD, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Della Volpe D, Dong XQ, Duan KK, Fan JH, Fan YZ, Fang J, Fang K, Feng CF, Feng L, Feng SH, Feng XT, Feng YL, Gabici S, Gao B, Gao CD, Gao LQ, Gao Q, Gao W, Gao WK, Ge MM, Geng LS, Giacinti G, Gong GH, Gou QB, Gu MH, Guo FL, Guo XL, Guo YQ, Guo YY, Han YA, He HH, He HN, He JY, He XB, He Y, Heller M, Hor YK, Hou BW, Hou C, Hou X, Hu HB, Hu Q, Hu SC, Huang DH, Huang TQ, Huang WJ, Huang XT, Huang XY, Huang Y, Huang ZC, Ji XL, Jia HY, Jia K, Jiang K, Jiang XW, Jiang ZJ, Jin M, Kang MM, Ke T, Kuleshov D, Kurinov K, Li BB, Li C, Li C, Li D, Li F, Li HB, Li HC, Li HY, Li J, Li J, Li J, Li K, Li WL, Li WL, Li XR, Li X, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu H, Liu HD, Liu J, Liu JL, Liu JY, Liu MY, Liu RY, Liu SM, Liu W, Liu Y, Liu YN, Lu R, Luo Q, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Min Z, Mitthumsiri W, Mu HJ, Nan YC, Neronov A, Ou ZW, Pang BY, Pattarakijwanich P, Pei ZY, Qi MY, Qi YQ, Qiao BQ, Qin JJ, Ruffolo D, Sáiz A, Semikoz D, Shao CY, Shao L, Shchegolev O, Sheng XD, Shu FW, Song HC, Stenkin YV, Stepanov V, Su Y, Sun QN, Sun XN, Sun ZB, Tam PHT, Tang QW, Tang ZB, Tian WW, Wang C, Wang CB, Wang GW, Wang HG, Wang HH, Wang JC, Wang K, Wang LP, Wang LY, Wang PH, Wang R, Wang W, Wang XG, Wang XY, Wang Y, Wang YD, Wang YJ, Wang ZH, Wang ZX, Wang Z, Wang Z, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu S, Wu XF, Wu YS, Xi SQ, Xia J, Xia JJ, Xiang GM, Xiao DX, Xiao G, Xin GG, Xin YL, Xing Y, Xiong Z, Xu DL, Xu RF, Xu RX, Xu WL, Xue L, Yan DH, Yan JZ, Yan T, Yang CW, Yang F, Yang FF, Yang HW, Yang JY, Yang LL, Yang MJ, Yang RZ, Yang SB, Yao YH, Yao ZG, Ye YM, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Yue H, Zeng HD, Zeng TX, Zeng W, Zha M, Zhang BB, Zhang F, Zhang HM, Zhang HY, Zhang JL, Zhang LX, Zhang L, Zhang PF, Zhang PP, Zhang R, Zhang SB, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang YF, Zhang Y, Zhang Y, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zheng F, Zhou B, Zhou H, Zhou JN, Zhou M, Zhou P, Zhou R, Zhou XX, Zhu CG, Zhu FR, Zhu H, Zhu KJ, and Zuo X
Abstract: In this Letter we try to search for signals generated by ultraheavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible γ rays by dark matter annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of the LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter that have low fluxes of astrophysical γ-ray background while having large amount of dark matter. By analyzing more than 700 days of observational data at LHAASO, no significant dark matter signal from 1 TeV to 1 EeV is detected. Accordingly we derive the most stringent constraints on the ultraheavy dark matter annihilation cross section up to EeV. The constraints on the lifetime of dark matter in decay mode are also derived.
Published: 2024
Full Text: View/download PDF

37. Search for a Sub-eV Sterile Neutrino Using Daya Bay's Full Dataset.

Author: An FP, Bai WD, Balantekin AB, Bishai M, Blyth S, Cao GF, Cao J, Chang JF, Chang Y, Chen HS, Chen HY, Chen SM, Chen Y, Chen YX, Chen ZY, Cheng J, Cheng YC, Cheng ZK, Cherwinka JJ, Chu MC, Cummings JP, Dalager O, Deng FS, Ding XY, Ding YY, Diwan MV, Dohnal T, Dolzhikov D, Dove J, Dugas KV, Duyang HY, Dwyer DA, Gallo JP, Gonchar M, Gong GH, Gong H, Gu WQ, Guo JY, Guo L, Guo XH, Guo YH, Guo Z, Hackenburg RW, Han Y, Hans S, He M, Heeger KM, Heng YK, Hor YK, Hsiung YB, Hu BZ, Hu JR, Hu T, Hu ZJ, Huang HX, Huang JH, Huang XT, Huang YB, Huber P, Jaffe DE, Jen KL, Ji XL, Ji XP, Johnson RA, Jones D, Kang L, Kettell SH, Kohn S, Kramer M, Langford TJ, Lee J, Lee JHC, Lei RT, Leitner R, Leung JKC, Li F, Li HL, Li JJ, Li QJ, Li RH, Li S, Li S, Li SC, Li WD, Li XN, Li XQ, Li YF, Li ZB, Liang H, Lin CJ, Lin GL, Lin S, Ling JJ, Link JM, Littenberg L, Littlejohn BR, Liu JC, Liu JL, Liu JX, Lu C, Lu HQ, Luk KB, Ma BZ, Ma XB, Ma XY, Ma YQ, Mandujano RC, Marshall C, McDonald KT, McKeown RD, Meng Y, Napolitano J, Naumov D, Naumova E, Nguyen TMT, Ochoa-Ricoux JP, Olshevskiy A, Park J, Patton S, Peng JC, Pun CSJ, Qi FZ, Qi M, Qian X, Raper N, Ren J, Morales Reveco C, Rosero R, Roskovec B, Ruan XC, Russell B, Steiner H, Sun JL, Tmej T, Tse WH, Tull CE, Tung YC, Viren B, Vorobel V, Wang CH, Wang J, Wang M, Wang NY, Wang RG, Wang W, Wang X, Wang YF, Wang Z, Wang Z, Wang ZM, Wei HY, Wei LH, Wei W, Wen LJ, Whisnant K, White CG, Wong HLH, Worcester E, Wu DR, Wu Q, Wu WJ, Xia DM, Xie ZQ, Xing ZZ, Xu HK, Xu JL, Xu T, Xue T, Yang CG, Yang L, Yang YZ, Yao HF, Ye M, Yeh M, Young BL, Yu HZ, Yu ZY, Yuan CZ, Yue BB, Zavadskyi V, Zeng S, Zeng Y, Zhan L, Zhang C, Zhang FY, Zhang HH, Zhang JL, Zhang JW, Zhang QM, Zhang SQ, Zhang XT, Zhang YM, Zhang YX, Zhang YY, Zhang ZJ, Zhang ZP, Zhang ZY, Zhao J, Zhao RZ, Zhou L, Zhuang HL, and Zou JH
Abstract: This Letter presents results of a search for the mixing of a sub-eV sterile neutrino with three active neutrinos based on the full data sample of the Daya Bay Reactor Neutrino Experiment, collected during 3158 days of detector operation, which contains 5.55×10^{6} reactor ν[over ¯]_{e} candidates identified as inverse beta-decay interactions followed by neutron capture on gadolinium. The analysis benefits from a doubling of the statistics of our previous result and from improvements of several important systematic uncertainties. No significant oscillation due to mixing of a sub-eV sterile neutrino with active neutrinos was found. Exclusion limits are set by both Feldman-Cousins and CLs methods. Light sterile neutrino mixing with sin^{2}2θ_{14}≳0.01 can be excluded at 95% confidence level in the region of 0.01 eV^{2}≲|Δm_{41}^{2}|≲0.1 eV^{2}. This result represents the world-leading constraints in the region of 2×10^{-4} eV^{2}≲|Δm_{41}^{2}|≲0.2 eV^{2}.
Published: 2024
Full Text: View/download PDF

38. Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A.

Author: Cao Z, Aharonian F, Axikegu, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Bian W, Bukevich AV, Cao Q, Cao WY, Cao Z, Chang J, Chang JF, Chen AM, Chen ES, Chen HX, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen S, Chen SH, Chen SZ, Chen TL, Chen Y, Cheng N, Cheng YD, Cui MY, Cui SW, Cui XH, Cui YD, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Dong XQ, Duan KK, Fan JH, Fan YZ, Fang J, Fang JH, Fang K, Feng CF, Feng H, Feng L, Feng SH, Feng XT, Feng Y, Feng YL, Gabici S, Gao B, Gao CD, Gao Q, Gao W, Gao WK, Ge MM, Geng LS, Giacinti G, Gong GH, Gou QB, Gu MH, Guo FL, Guo XL, Guo YQ, Guo YY, Han YA, Hasan M, He HH, He HN, He JY, He Y, Hor YK, Hou BW, Hou C, Hou X, Hu HB, Hu Q, Hu SC, Huang DH, Huang TQ, Huang WJ, Huang XT, Huang XY, Huang Y, Ji XL, Jia HY, Jia K, Jiang K, Jiang XW, Jiang ZJ, Jin M, Kang MM, Karpikov I, Kuleshov D, Kurinov K, Li BB, Li CM, Li C, Li C, Li D, Li F, Li HB, Li HC, Li J, Li J, Li K, Li SD, Li WL, Li WL, Li XR, Li X, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu DB, Liu H, Liu HD, Liu J, Liu JL, Liu MY, Liu RY, Liu SM, Liu W, Liu Y, Liu YN, Luo Q, Luo Y, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Min Z, Mitthumsiri W, Mu HJ, Nan YC, Neronov A, Ou LJ, Pattarakijwanich P, Pei ZY, Qi JC, Qi MY, Qiao BQ, Qin JJ, Raza A, Ruffolo D, Sáiz A, Saeed M, Semikoz D, Shao L, Shchegolev O, Sheng XD, Shu FW, Song HC, Stenkin YV, Stepanov V, Su Y, Sun DX, Sun QN, Sun XN, Sun ZB, Takata J, Tam PHT, Tang QW, Tang R, Tang ZB, Tian WW, Wang C, Wang CB, Wang GW, Wang HG, Wang HH, Wang JC, Wang K, Wang K, Wang LP, Wang LY, Wang PH, Wang R, Wang W, Wang XG, Wang XY, Wang Y, Wang YD, Wang YJ, Wang ZH, Wang ZX, Wang Z, Wang Z, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu QW, Wu S, Wu XF, Wu YS, Xi SQ, Xia J, Xiang GM, Xiao DX, Xiao G, Xin YL, Xing Y, Xiong DR, Xiong Z, Xu DL, Xu RF, Xu RX, Xu WL, Xue L, Yan DH, Yan JZ, Yan T, Yang CW, Yang CY, Yang F, Yang FF, Yang LL, Yang MJ, Yang RZ, Yang WX, Yao YH, Yao ZG, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Yue H, Zeng HD, Zeng TX, Zeng W, Zha M, Zhang BB, Zhang F, Zhang H, Zhang HM, Zhang HY, Zhang JL, Zhang L, Zhang PF, Zhang PP, Zhang R, Zhang SB, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang YF, Zhang Y, Zhang Y, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zhao XH, Zheng F, Zhong WJ, Zhou B, Zhou H, Zhou JN, Zhou M, Zhou P, Zhou R, Zhou XX, Zhou XX, Zhu BY, Zhu CG, Zhu FR, Zhu H, Zhu KJ, Zou YC, and Zuo X
Abstract: We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.
Published: 2024
Full Text: View/download PDF

39. Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A.

Author: Cao Z, Aharonian F, An Q, Axikegu, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Cai JT, Cao Q, Cao WY, Cao Z, Chang J, Chang JF, Chen AM, Chen ES, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen SH, Chen SZ, Chen TL, Chen Y, Cheng N, Cheng YD, Cui MY, Cui SW, Cui XH, Cui YD, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Della Volpe D, Dong XQ, Duan KK, Fan JH, Fan YZ, Fang J, Fang K, Feng CF, Feng L, Feng SH, Feng XT, Feng YL, Gabici S, Gao B, Gao CD, Gao LQ, Gao Q, Gao W, Gao WK, Ge MM, Geng LS, Giacinti G, Gong GH, Gou QB, Gu MH, Guo FL, Guo XL, Guo YQ, Guo YY, Han YA, He HH, He HN, He JY, He XB, He Y, Heller M, Hor YK, Hou BW, Hou C, Hou X, Hu HB, Hu Q, Hu SC, Huang DH, Huang TQ, Huang WJ, Huang XT, Huang XY, Huang Y, Huang ZC, Ji XL, Jia HY, Jia K, Jiang K, Jiang XW, Jiang ZJ, Jin M, Kang MM, Ke T, Kuleshov D, Kurinov K, Li BB, Li C, Li C, Li D, Li F, Li HB, Li HC, Li HY, Li J, Li J, Li J, Li K, Li WL, Li WL, Li XR, Li X, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu H, Liu HD, Liu J, Liu JL, Liu JY, Liu MY, Liu RY, Liu SM, Liu W, Liu Y, Liu YN, Lu R, Luo Q, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Min Z, Mitthumsiri W, Mu HJ, Nan YC, Neronov A, Ou ZW, Pang BY, Pattarakijwanich P, Pei ZY, Qi MY, Qi YQ, Qiao BQ, Qin JJ, Ruffolo D, Sáiz A, Semikoz D, Shao CY, Shao L, Shchegolev O, Sheng XD, Shu FW, Song HC, Stenkin YV, Stepanov V, Su Y, Sun QN, Sun XN, Sun ZB, Tam PHT, Tang QW, Tang ZB, Tian WW, Wang C, Wang CB, Wang GW, Wang HG, Wang HH, Wang JC, Wang K, Wang LP, Wang LY, Wang PH, Wang R, Wang W, Wang XG, Wang XY, Wang Y, Wang YD, Wang YJ, Wang ZH, Wang ZX, Wang Z, Wang Z, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu S, Wu XF, Wu YS, Xi SQ, Xia J, Xia JJ, Xiang GM, Xiao DX, Xiao G, Xin GG, Xin YL, Xing Y, Xiong Z, Xu DL, Xu RF, Xu RX, Xu WL, Xue L, Yan DH, Yan JZ, Yan T, Yang CW, Yang F, Yang FF, Yang HW, Yang JY, Yang LL, Yang MJ, Yang RZ, Yang SB, Yao YH, Yao ZG, Ye YM, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Yue H, Zeng HD, Zeng TX, Zeng W, Zha M, Zhang BB, Zhang F, Zhang HM, Zhang HY, Zhang JL, Zhang LX, Zhang L, Zhang PF, Zhang PP, Zhang R, Zhang SB, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang YF, Zhang Y, Zhang Y, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zheng F, Zhou B, Zhou H, Zhou JN, Zhou M, Zhou P, Zhou R, Zhou XX, Zhu CG, Zhu FR, Zhu H, Zhu KJ, and Zuo X
Abstract: The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.
Published: 2023
Full Text: View/download PDF

40. A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst.

Author: Cao Z, Aharonian F, An Q, Axikegu, Bai LX, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Cai JT, Cao Q, Cao WY, Cao Z, Chang J, Chang JF, Chen ES, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen SH, Chen SZ, Chen TL, Chen Y, Cheng HL, Cheng N, Cheng YD, Cui SW, Cui XH, Cui YD, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Della Volpe D, Dong XQ, Duan KK, Fan JH, Fan YZ, Fang J, Fang K, Feng CF, Feng L, Feng SH, Feng XT, Feng YL, Gao B, Gao CD, Gao LQ, Gao Q, Gao W, Gao WK, Ge MM, Geng LS, Gong GH, Gou QB, Gu MH, Guo FL, Guo XL, Guo YQ, Guo YY, Han YA, He HH, He HN, He JY, He XB, He Y, Heller M, Hor YK, Hou BW, Hou C, Hou X, Hu HB, Hu Q, Hu SC, Huang DH, Huang TQ, Huang WJ, Huang XT, Huang XY, Huang Y, Huang ZC, Ji XL, Jia HY, Jia K, Jiang K, Jiang XW, Jiang ZJ, Jin M, Kang MM, Ke T, Kuleshov D, Kurinov K, Li BB, Li C, Li C, Li D, Li F, Li HB, Li HC, Li HY, Li J, Li J, Li J, Li K, Li WL, Li WL, Li XR, Li X, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu H, Liu HD, Liu J, Liu JL, Liu JL, Liu JS, Liu JY, Liu MY, Liu RY, Liu SM, Liu W, Liu Y, Liu YN, Long WJ, Lu R, Luo Q, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Min Z, Mitthumsiri W, Nan YC, Ou ZW, Pang BY, Pattarakijwanich P, Pei ZY, Qi MY, Qi YQ, Qiao BQ, Qin JJ, Ruffolo D, Sáiz A, Shao CY, Shao L, Shchegolev O, Sheng XD, Song HC, Stenkin YV, Stepanov V, Su Y, Sun QN, Sun XN, Sun ZB, Tam PHT, Tang ZB, Tian WW, Wang C, Wang CB, Wang GW, Wang HG, Wang HH, Wang JC, Wang JS, Wang K, Wang LP, Wang LY, Wang PH, Wang R, Wang W, Wang XG, Wang XY, Wang Y, Wang YD, Wang YJ, Wang ZH, Wang ZX, Wang Z, Wang Z, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu S, Wu XF, Wu YS, Xi SQ, Xia J, Xia JJ, Xiang GM, Xiao DX, Xiao G, Xin GG, Xin YL, Xing Y, Xiong Z, Xu DL, Xu RF, Xu RX, Xue L, Yan DH, Yan JZ, Yan T, Yang CW, Yang F, Yang FF, Yang HW, Yang JY, Yang LL, Yang MJ, Yang RZ, Yang SB, Yao YH, Yao ZG, Ye YM, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Yue H, Zeng HD, Zeng TX, Zeng W, Zeng ZK, Zha M, Zhang B, Zhang BB, Zhang F, Zhang HM, Zhang HY, Zhang JL, Zhang LX, Zhang L, Zhang PF, Zhang PP, Zhang R, Zhang SB, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang YF, Zhang Y, Zhang Y, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zheng F, Zheng JH, Zhou B, Zhou H, Zhou JN, Zhou P, Zhou R, Zhou XX, Zhu CG, Zhu FR, Zhu H, Zhu KJ, and Zuo X
Abstract: Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory (LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger and then rose to a peak ~10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle of ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.
Published: 2023
Full Text: View/download PDF

41. Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations.

Author: Cao Z, Aharonian F, An Q, Axikegu, Bai LX, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Cai JT, Cao Z, Chang J, Chang JF, Chen ES, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen SH, Chen SZ, Chen TL, Chen Y, Cheng HL, Cheng N, Cheng YD, Cui SW, Cui XH, Cui YD, D'Ettorre Piazzoli B, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Della Volpe D, Duan KK, Fan JH, Fan YZ, Fan ZX, Fang J, Fang K, Feng CF, Feng L, Feng SH, Feng XT, Feng YL, Gao B, Gao CD, Gao LQ, Gao Q, Gao W, Gao WK, Ge MM, Geng LS, Gong GH, Gou QB, Gu MH, Guo FL, Guo JG, Guo XL, Guo YQ, Guo YY, Han YA, He HH, He HN, He SL, He XB, He Y, Heller M, Hor YK, Hou C, Hou X, Hu HB, Hu Q, Hu S, Hu SC, Hu XJ, Huang DH, Huang WH, Huang XT, Huang XY, Huang Y, Huang ZC, Ji XL, Jia HY, Jia K, Jiang K, Jiang ZJ, Jin M, Kang MM, Ke T, Kuleshov D, Levochkin K, Li BB, Li C, Li C, Li F, Li HB, Li HC, Li HY, Li J, Li J, Li J, Li K, Li WL, Li XR, Li X, Li X, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu H, Liu HD, Liu J, Liu JL, Liu JS, Liu JY, Liu MY, Liu RY, Liu SM, Liu W, Liu Y, Liu YN, Long WJ, Lu R, Luo Q, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Masood A, Min Z, Mitthumsiri W, Nan YC, Ou ZW, Pang BY, Pattarakijwanich P, Pei ZY, Qi MY, Qi YQ, Qiao BQ, Qin JJ, Ruffolo D, Sáiz A, Shao CY, Shao L, Shchegolev O, Sheng XD, Shi JY, Song HC, Stenkin YV, Stepanov V, Su Y, Sun QN, Sun XN, Sun ZB, Tam PHT, Tang ZB, Tian WW, Wang BD, Wang C, Wang H, Wang HG, Wang JC, Wang JS, Wang LP, Wang LY, Wang R, Wang RN, Wang W, Wang XG, Wang XY, Wang Y, Wang YD, Wang YJ, Wang YP, Wang ZH, Wang ZX, Wang Z, Wang Z, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu S, Wu XF, Wu YS, Xi SQ, Xia J, Xia JJ, Xiang GM, Xiao DX, Xiao G, Xin GG, Xin YL, Xing Y, Xiong Z, Xu DL, Xu RX, Xue L, Yan DH, Yan JZ, Yang CW, Yang FF, Yang HW, Yang JY, Yang LL, Yang MJ, Yang RZ, Yang SB, Yao YH, Yao ZG, Ye YM, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Yue H, Zeng HD, Zeng TX, Zeng W, Zeng ZK, Zha M, Zhai XX, Zhang BB, Zhang F, Zhang HM, Zhang HY, Zhang JL, Zhang LX, Zhang L, Zhang L, Zhang PF, Zhang PP, Zhang R, Zhang SB, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang YF, Zhang YL, Zhang Y, Zhang Y, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zheng F, Zheng Y, Zhou B, Zhou H, Zhou JN, Zhou P, Zhou R, Zhou XX, Zhu CG, Zhu FR, Zhu H, Zhu KJ, Zuo X, Ando S, Chianese M, Fiorillo DFG, Miele G, and Ng KCY
Abstract: The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9} GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.
Published: 2022
Full Text: View/download PDF

42. Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT.

Author: An FP, Andriamirado M, Balantekin AB, Band HR, Bass CD, Bergeron DE, Berish D, Bishai M, Blyth S, Bowden NS, Bryan CD, Cao GF, Cao J, Chang JF, Chang Y, Chen HS, Chen SM, Chen Y, Chen YX, Cheng J, Cheng ZK, Cherwinka JJ, Chu MC, Classen T, Conant AJ, Cummings JP, Dalager O, Deichert G, Delgado A, Deng FS, Ding YY, Diwan MV, Dohnal T, Dolinski MJ, Dolzhikov D, Dove J, Dvořák M, Dwyer DA, Erickson A, Foust BT, Gaison JK, Galindo-Uribarri A, Gallo JP, Gilbert CE, Gonchar M, Gong GH, Gong H, Grassi M, Gu WQ, Guo JY, Guo L, Guo XH, Guo YH, Guo Z, Hackenburg RW, Hans S, Hansell AB, He M, Heeger KM, Heffron B, Heng YK, Hor YK, Hsiung YB, Hu BZ, Hu JR, Hu T, Hu ZJ, Huang HX, Huang JH, Huang XT, Huang YB, Huber P, Koblanski J, Jaffe DE, Jayakumar S, Jen KL, Ji XL, Ji XP, Johnson RA, Jones DC, Kang L, Kettell SH, Kohn S, Kramer M, Kyzylova O, Lane CE, Langford TJ, LaRosa J, Lee J, Lee JHC, Lei RT, Leitner R, Leung JKC, Li F, Li HL, Li JJ, Li QJ, Li RH, Li S, Li SC, Li WD, Li XN, Li XQ, Li YF, Li ZB, Liang H, Lin CJ, Lin GL, Lin S, Ling JJ, Link JM, Littenberg L, Littlejohn BR, Liu JC, Liu JL, Liu JX, Lu C, Lu HQ, Lu X, Luk KB, Ma BZ, Ma XB, Ma XY, Ma YQ, Mandujano RC, Maricic J, Marshall C, McDonald KT, McKeown RD, Mendenhall MP, Meng Y, Meyer AM, Milincic R, Mueller PE, Mumm HP, Napolitano J, Naumov D, Naumova E, Neilson R, Nguyen TMT, Nikkel JA, Nour S, Ochoa-Ricoux JP, Olshevskiy A, Palomino JL, Pan HR, Park J, Patton S, Peng JC, Pun CSJ, Pushin DA, Qi FZ, Qi M, Qian X, Raper N, Ren J, Morales Reveco C, Rosero R, Roskovec B, Ruan XC, Searles M, Steiner H, Sun JL, Surukuchi PT, Tmej T, Treskov K, Tse WH, Tull CE, Tyra MA, Varner RL, Venegas-Vargas D, Viren B, Vorobel V, Wang CH, Wang J, Wang M, Wang NY, Wang RG, Wang W, Wang W, Wang X, Wang Y, Wang YF, Wang Z, Wang Z, Wang ZM, Weatherly PB, Wei HY, Wei LH, Wen LJ, Whisnant K, White C, Wilhelmi J, Wong HLH, Woolverton A, Worcester E, Wu DR, Wu FL, Wu Q, Wu WJ, Xia DM, Xie ZQ, Xing ZZ, Xu HK, Xu JL, Xu T, Xue T, Yang CG, Yang L, Yang YZ, Yao HF, Ye M, Yeh M, Young BL, Yu HZ, Yu ZY, Yue BB, Zavadskyi V, Zeng S, Zeng Y, Zhan L, Zhang C, Zhang FY, Zhang HH, Zhang JW, Zhang QM, Zhang SQ, Zhang X, Zhang XT, Zhang YM, Zhang YX, Zhang YY, Zhang ZJ, Zhang ZP, Zhang ZY, Zhao J, Zhao RZ, Zhou L, Zhuang HL, and Zou JH
Abstract: A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.
Published: 2022
Full Text: View/download PDF

43. Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO.

Author: Cao Z, Aharonian F, An Q, Axikegu, Bai LX, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Cai H, Cai JT, Cao Z, Chang J, Chang JF, Chen BM, Chen ES, Chen J, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen SH, Chen SZ, Chen TL, Chen XL, Chen Y, Cheng N, Cheng YD, Cui SW, Cui XH, Cui YD, Piazzoli BD, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Della Volpe D, Dong XJ, Duan KK, Fan JH, Fan YZ, Fan ZX, Fang J, Fang K, Feng CF, Feng L, Feng SH, Feng YL, Gao B, Gao CD, Gao LQ, Gao Q, Gao W, Ge MM, Geng LS, Gong GH, Gou QB, Gu MH, Guo FL, Guo JG, Guo XL, Guo YQ, Guo YY, Han YA, He HH, He HN, He JC, He SL, He XB, He Y, Heller M, Hor YK, Hou C, Hou X, Hu HB, Hu S, Hu SC, Hu XJ, Huang DH, Huang QL, Huang WH, Huang XT, Huang XY, Huang ZC, Ji F, Ji XL, Jia HY, Jiang K, Jiang ZJ, Jin C, Ke T, Kuleshov D, Levochkin K, Li BB, Li C, Li C, Li F, Li HB, Li HC, Li HY, Li J, Li J, Li K, Li WL, Li XR, Li X, Li X, Li Y, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu H, Liu HD, Liu J, Liu JL, Liu JS, Liu JY, Liu MY, Liu RY, Liu SM, Liu W, Liu Y, Liu YN, Liu ZX, Long WJ, Lu R, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Masood A, Min Z, Mitthumsiri W, Montaruli T, Nan YC, Pang BY, Pattarakijwanich P, Pei ZY, Qi MY, Qi YQ, Qiao BQ, Qin JJ, Ruffolo D, Rulev V, Sáiz A, Shao L, Shchegolev O, Sheng XD, Shi JR, Song HC, Stenkin YV, Stepanov V, Su Y, Sun QN, Sun XN, Sun ZB, Tam PHT, Tang ZB, Tian WW, Wang BD, Wang C, Wang H, Wang HG, Wang JC, Wang JS, Wang LP, Wang LY, Wang RN, Wang W, Wang W, Wang XG, Wang XJ, Wang XY, Wang Y, Wang YD, Wang YJ, Wang YP, Wang ZH, Wang ZX, Wang Z, Wang Z, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu S, Wu WX, Wu XF, Xi SQ, Xia J, Xia JJ, Xiang GM, Xiao DX, Xiao G, Xiao HB, Xin GG, Xin YL, Xing Y, Xu DL, Xu RX, Xue L, Yan DH, Yan JZ, Yang CW, Yang FF, Yang JY, Yang LL, Yang MJ, Yang RZ, Yang SB, Yao YH, Yao ZG, Ye YM, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Zeng HD, Zeng TX, Zeng W, Zeng ZK, Zha M, Zhai XX, Zhang BB, Zhang HM, Zhang HY, Zhang JL, Zhang JW, Zhang LX, Zhang L, Zhang L, Zhang PF, Zhang PP, Zhang R, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang YF, Zhang YL, Zhang Y, Zhang Y, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zheng F, Zheng Y, Zhou B, Zhou H, Zhou JN, Zhou P, Zhou R, Zhou XX, Zhu CG, Zhu FR, Zhu H, Zhu KJ, and Zuo X
Abstract: Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.
Published: 2022
Full Text: View/download PDF

44. Peta-electron volt gamma-ray emission from the Crab Nebula.

Author: Cao Z, Aharonian F, An Q, Axikegu, Bai LX, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Cai H, Cai JT, Cao Z, Chang J, Chang JF, Chen BM, Chen ES, Chen J, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen SH, Chen SZ, Chen TL, Chen XL, Chen Y, Cheng N, Cheng YD, Cui SW, Cui XH, Cui YD, D'Ettorre Piazzoli B, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Della Volpe D, Dong XJ, Duan KK, Fan JH, Fan YZ, Fan ZX, Fang J, Fang K, Feng CF, Feng L, Feng SH, Feng YL, Gao B, Gao CD, Gao LQ, Gao Q, Gao W, Ge MM, Geng LS, Gong GH, Gou QB, Gu MH, Guo FL, Guo JG, Guo XL, Guo YQ, Guo YY, Han YA, He HH, He HN, He JC, He SL, He XB, He Y, Heller M, Hor YK, Hou C, Hou X, Hu HB, Hu S, Hu SC, Hu XJ, Huang DH, Huang QL, Huang WH, Huang XT, Huang XY, Huang ZC, Ji F, Ji XL, Jia HY, Jiang K, Jiang ZJ, Jin C, Ke T, Kuleshov D, Levochkin K, Li BB, Li C, Li C, Li F, Li HB, Li HC, Li HY, Li J, Li J, Li K, Li WL, Li XR, Li X, Li X, Li Y, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu H, Liu HD, Liu J, Liu JL, Liu JS, Liu JY, Liu MY, Liu RY, Liu SM, Liu W, Liu Y, Liu YN, Liu ZX, Long WJ, Lu R, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Masood A, Min Z, Mitthumsiri W, Montaruli T, Nan YC, Pang BY, Pattarakijwanich P, Pei ZY, Qi MY, Qi YQ, Qiao BQ, Qin JJ, Ruffolo D, Rulev V, Saiz A, Shao L, Shchegolev O, Sheng XD, Shi JY, Song HC, Stenkin YV, Stepanov V, Su Y, Sun QN, Sun XN, Sun ZB, Tam PHT, Tang ZB, Tian WW, Wang BD, Wang C, Wang H, Wang HG, Wang JC, Wang JS, Wang LP, Wang LY, Wang RN, Wang W, Wang W, Wang XG, Wang XJ, Wang XY, Wang Y, Wang YD, Wang YJ, Wang YP, Wang ZH, Wang ZX, Wang Z, Wang Z, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu S, Wu WX, Wu XF, Xi SQ, Xia J, Xia JJ, Xiang GM, Xiao DX, Xiao G, Xiao HB, Xin GG, Xin YL, Xing Y, Xu DL, Xu RX, Xue L, Yan DH, Yan JZ, Yang CW, Yang FF, Yang JY, Yang LL, Yang MJ, Yang RZ, Yang SB, Yao YH, Yao ZG, Ye YM, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Zeng HD, Zeng TX, Zeng W, Zeng ZK, Zha M, Zhai XX, Zhang BB, Zhang HM, Zhang HY, Zhang JL, Zhang JW, Zhang LX, Zhang L, Zhang L, Zhang PF, Zhang PP, Zhang R, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang YF, Zhang YL, Zhang Y, Zhang Y, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zheng F, Zheng Y, Zhou B, Zhou H, Zhou JN, Zhou P, Zhou R, Zhou XX, Zhu CG, Zhu FR, Zhu H, Zhu KJ, and Zuo X
Abstract: The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10 -4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10 36 ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
Published: 2021
Full Text: View/download PDF

45. Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A.

Author: Aharonian F, An Q, Axikegu, Bai LX, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Cai H, Cai JT, Cao Z, Cao Z, Chang J, Chang JF, Chang XC, Chen BM, Chen J, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen SH, Chen SZ, Chen TL, Chen XL, Chen Y, Cheng N, Cheng YD, Cui SW, Cui XH, Cui YD, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Della Volpe D, D'Ettorre Piazzoli B, Dong XJ, Fan JH, Fan YZ, Fan ZX, Fang J, Fang K, Feng CF, Feng L, Feng SH, Feng YL, Gao B, Gao CD, Gao Q, Gao W, Ge MM, Geng LS, Gong GH, Gou QB, Gu MH, Guo JG, Guo XL, Guo YQ, Guo YY, Han YA, He HH, He HN, He JC, He SL, He XB, He Y, Heller M, Hor YK, Hou C, Hou X, Hu HB, Hu S, Hu SC, Hu XJ, Huang DH, Huang QL, Huang WH, Huang XT, Huang ZC, Ji F, Ji XL, Jia HY, Jiang K, Jiang ZJ, Jin C, Kuleshov D, Levochkin K, Li BB, Li C, Li C, Li F, Li HB, Li HC, Li HY, Li J, Li K, Li WL, Li X, Li X, Li XR, Li Y, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu H, Liu HD, Liu J, Liu JL, Liu JS, Liu JY, Liu MY, Liu RY, Liu SM, Liu W, Liu YN, Liu ZX, Long WJ, Lu R, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Masood A, Mitthumsiri W, Montaruli T, Nan YC, Pang BY, Pattarakijwanich P, Pei ZY, Qi MY, Ruffolo D, Rulev V, Sáiz A, Shao L, Shchegolev O, Sheng XD, Shi JR, Song HC, Stenkin YV, Stepanov V, Sun QN, Sun XN, Sun ZB, Tam PHT, Tang ZB, Tian WW, Wang BD, Wang C, Wang H, Wang HG, Wang JC, Wang JS, Wang LP, Wang LY, Wang RN, Wang W, Wang W, Wang XG, Wang XJ, Wang XY, Wang YD, Wang YJ, Wang YP, Wang Z, Wang Z, Wang ZH, Wang ZX, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu S, Wu WX, Wu XF, Xi SQ, Xia J, Xia JJ, Xiang GM, Xiao G, Xiao HB, Xin GG, Xin YL, Xing Y, Xu DL, Xu RX, Xue L, Yan DH, Yang CW, Yang FF, Yang JY, Yang LL, Yang MJ, Yang RZ, Yang SB, Yao YH, Yao ZG, Ye YM, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Zeng HD, Zeng TX, Zeng W, Zeng ZK, Zha M, Zhai XX, Zhang BB, Zhang HM, Zhang HY, Zhang JL, Zhang JW, Zhang L, Zhang L, Zhang LX, Zhang PF, Zhang PP, Zhang R, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang Y, Zhang Y, Zhang YF, Zhang YL, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zheng F, Zheng Y, Zhou B, Zhou H, Zhou JN, Zhou P, Zhou R, Zhou XX, Zhu CG, Zhu FR, Zhu H, Zhu KJ, Zuo X, and Huang XY
Abstract: We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25 TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160 TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.
Published: 2021
Full Text: View/download PDF

46. Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources.

Author: Cao Z, Aharonian FA, An Q, Axikegu, Bai LX, Bai YX, Bao YW, Bastieri D, Bi XJ, Bi YJ, Cai H, Cai JT, Cao Z, Chang J, Chang JF, Chang XC, Chen BM, Chen J, Chen L, Chen L, Chen L, Chen MJ, Chen ML, Chen QH, Chen SH, Chen SZ, Chen TL, Chen XL, Chen Y, Cheng N, Cheng YD, Cui SW, Cui XH, Cui YD, Dai BZ, Dai HL, Dai ZG, Danzengluobu, Della Volpe D, D Ettorre Piazzoli B, Dong XJ, Fan JH, Fan YZ, Fan ZX, Fang J, Fang K, Feng CF, Feng L, Feng SH, Feng YL, Gao B, Gao CD, Gao Q, Gao W, Ge MM, Geng LS, Gong GH, Gou QB, Gu MH, Guo JG, Guo XL, Guo YQ, Guo YY, Han YA, He HH, He HN, He JC, He SL, He XB, He Y, Heller M, Hor YK, Hou C, Hou X, Hu HB, Hu S, Hu SC, Hu XJ, Huang DH, Huang QL, Huang WH, Huang XT, Huang ZC, Ji F, Ji XL, Jia HY, Jiang K, Jiang ZJ, Jin C, Kuleshov D, Levochkin K, Li BB, Li C, Li C, Li F, Li HB, Li HC, Li HY, Li J, Li K, Li WL, Li X, Li X, Li XR, Li Y, Li YZ, Li Z, Li Z, Liang EW, Liang YF, Lin SJ, Liu B, Liu C, Liu D, Liu H, Liu HD, Liu J, Liu JL, Liu JS, Liu JY, Liu MY, Liu RY, Liu SM, Liu W, Liu YN, Liu ZX, Long WJ, Lu R, Lv HK, Ma BQ, Ma LL, Ma XH, Mao JR, Masood A, Mitthumsiri W, Montaruli T, Nan YC, Pang BY, Pattarakijwanich P, Pei ZY, Qi MY, Ruffolo D, Rulev V, Sáiz A, Shao L, Shchegolev O, Sheng XD, Shi JR, Song HC, Stenkin YV, Stepanov V, Sun QN, Sun XN, Sun ZB, Tam PHT, Tang ZB, Tian WW, Wang BD, Wang C, Wang H, Wang HG, Wang JC, Wang JS, Wang LP, Wang LY, Wang RN, Wang W, Wang W, Wang XG, Wang XJ, Wang XY, Wang YD, Wang YJ, Wang YP, Wang Z, Wang Z, Wang ZH, Wang ZX, Wei DM, Wei JJ, Wei YJ, Wen T, Wu CY, Wu HR, Wu S, Wu WX, Wu XF, Xi SQ, Xia J, Xia JJ, Xiang GM, Xiao G, Xiao HB, Xin GG, Xin YL, Xing Y, Xu DL, Xu RX, Xue L, Yan DH, Yang CW, Yang FF, Yang JY, Yang LL, Yang MJ, Yang RZ, Yang SB, Yao YH, Yao ZG, Ye YM, Yin LQ, Yin N, You XH, You ZY, Yu YH, Yuan Q, Zeng HD, Zeng TX, Zeng W, Zeng ZK, Zha M, Zhai XX, Zhang BB, Zhang HM, Zhang HY, Zhang JL, Zhang JW, Zhang L, Zhang L, Zhang LX, Zhang PF, Zhang PP, Zhang R, Zhang SR, Zhang SS, Zhang X, Zhang XP, Zhang Y, Zhang Y, Zhang YF, Zhang YL, Zhao B, Zhao J, Zhao L, Zhao LZ, Zhao SP, Zheng F, Zheng Y, Zhou B, Zhou H, Zhou JN, Zhou P, Zhou R, Zhou XX, Zhu CG, Zhu FR, Zhu H, Zhu KJ, and Zuo X
Abstract: The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10 15 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays 1 . The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2 ). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane 3-6 , unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.
Published: 2021
Full Text: View/download PDF

47. Clinical response of pigment epithelial detachment associated with neovascular age-related macular degeneration in switching treatment from Ranibizumab to Aflibercept.

Author: Tyagi P, Juma Z, Hor YK, Scott NW, Ionean A, and Santiago C
Subjects: Aged, Aged, 80 and over, Angiogenesis Inhibitors administration & dosage, Dose-Response Relationship, Drug, Drug Administration Schedule, Female, Follow-Up Studies, Humans, Intravitreal Injections, Male, Middle Aged, Receptors, Vascular Endothelial Growth Factor antagonists & inhibitors, Retinal Detachment etiology, Retinal Detachment pathology, Retrospective Studies, Time Factors, Tomography, Optical Coherence, Treatment Outcome, Wet Macular Degeneration diagnosis, Wet Macular Degeneration drug therapy, Drug Substitution methods, Ranibizumab administration & dosage, Receptors, Vascular Endothelial Growth Factor administration & dosage, Recombinant Fusion Proteins administration & dosage, Retinal Detachment drug therapy, Retinal Pigment Epithelium pathology, Visual Acuity physiology, Wet Macular Degeneration complications
Abstract: Background: To study the clinical outcomes of pigment epithelial detachment (PED) associated with neovascular age-related macular degeneration (nAMD) in patients switched from Ranibizumab to Aflibercept., Methods: Retrospective non-comparative case series. 50 eyes with active nAMD and fovea involving PED of ≥100 μm measured manually using the caliper on the OCT, initially treated with intravitreal Ranibizumab (0.5 mg/0.05 ml) and later switched to Aflibercept (2.0 mg/0.05 ml). The outcome measures of best corrected visual acuity (BCVA), PED height, PED width and number of injections were measured at baseline and at time point of switch, 4 months, 1 year and at last follow up visit post-switch. Three paired t-tests and Pearson's correlations were calculated to analyze variables at switch and change in variables at 1 year., Results: After switch to Aflibercept, the improvement of BCVA was 1.84 (p = 0.11), 1.74 (p = 0.21) and 1.16 (p = 0.45) letters, the change in PED height was - 65.6μm (p < 0.001), - 50.64μm (p = 0.007) and - 68.48μm (p < 0.001) and the change in PED width was - 36.6μm (p = 0.514), + 29.7μm (p = 0.922) and + 118.4μm (p = 0.210) at 4 months, 1 year and the last visit respectively. There was a moderate negative correlation between reduction in PED height at 1 year after switch and PED height at the time of switch to Aflibercept (r = - 0.474, p < 0.05)., Conclusion: The improvement in BCVA and change in PED width was not statistically significant however the reduction in PED height was significant after switching treatment to Aflibercept. The change in BCVA at 1 year after switch was not correlated with any of the analyzed anatomical characteristics of PED.
Published: 2018
Full Text: View/download PDF

48. Observation of electron-antineutrino disappearance at Daya Bay.

Author: An FP, Bai JZ, Balantekin AB, Band HR, Beavis D, Beriguete W, Bishai M, Blyth S, Boddy K, Brown RL, Cai B, Cao GF, Cao J, Carr R, Chan WT, Chang JF, Chang Y, Chasman C, Chen HS, Chen HY, Chen SJ, Chen SM, Chen XC, Chen XH, Chen XS, Chen Y, Chen YX, Cherwinka JJ, Chu MC, Cummings JP, Deng ZY, Ding YY, Diwan MV, Dong L, Draeger E, Du XF, Dwyer DA, Edwards WR, Ely SR, Fang SD, Fu JY, Fu ZW, Ge LQ, Ghazikhanian V, Gill RL, Goett J, Gonchar M, Gong GH, Gong H, Gornushkin YA, Greenler LS, Gu WQ, Guan MY, Guo XH, Hackenburg RW, Hahn RL, Hans S, He M, He Q, He WS, Heeger KM, Heng YK, Hinrichs P, Ho TH, Hor YK, Hsiung YB, Hu BZ, Hu T, Hu T, Huang HX, Huang HZ, Huang PW, Huang X, Huang XT, Huber P, Isvan Z, Jaffe DE, Jetter S, Ji XL, Ji XP, Jiang HJ, Jiang WQ, Jiao JB, Johnson RA, Kang L, Kettell SH, Kramer M, Kwan KK, Kwok MW, Kwok T, Lai CY, Lai WC, Lai WH, Lau K, Lebanowski L, Lee J, Lee MK, Leitner R, Leung JK, Leung KY, Lewis CA, Li B, Li F, Li GS, Li J, Li QJ, Li SF, Li WD, Li XB, Li XN, Li XQ, Li Y, Li ZB, Liang H, Liang J, Lin CJ, Lin GL, Lin SK, Lin SX, Lin YC, Ling JJ, Link JM, Littenberg L, Littlejohn BR, Liu BJ, Liu C, Liu DW, Liu H, Liu JC, Liu JL, Liu S, Liu X, Liu YB, Lu C, Lu HQ, Luk A, Luk KB, Luo T, Luo XL, Ma LH, Ma QM, Ma XB, Ma XY, Ma YQ, Mayes B, McDonald KT, McFarlane MC, McKeown RD, Meng Y, Mohapatra D, Morgan JE, Nakajima Y, Napolitano J, Naumov D, Nemchenok I, Newsom C, Ngai HY, Ngai WK, Nie YB, Ning Z, Ochoa-Ricoux JP, Oh D, Olshevski A, Pagac A, Patton S, Pearson C, Pec V, Peng JC, Piilonen LE, Pinsky L, Pun CS, Qi FZ, Qi M, Qian X, Raper N, Rosero R, Roskovec B, Ruan XC, Seilhan B, Shao BB, Shih K, Steiner H, Stoler P, Sun GX, Sun JL, Tam YH, Tanaka HK, Tang X, Themann H, Torun Y, Trentalange S, Tsai O, Tsang KV, Tsang RH, Tull C, Viren B, Virostek S, Vorobel V, Wang CH, Wang LS, Wang LY, Wang LZ, Wang M, Wang NY, Wang RG, Wang T, Wang W, Wang X, Wang X, Wang YF, Wang Z, Wang Z, Wang ZM, Webber DM, Wei YD, Wen LJ, Wenman DL, Whisnant K, White CG, Whitehead L, Whitten CA Jr, Wilhelmi J, Wise T, Wong HC, Wong HL, Wong J, Worcester ET, Wu FF, Wu Q, Xia DM, Xiang ST, Xiao Q, Xing ZZ, Xu G, Xu J, Xu J, Xu JL, Xu W, Xu Y, Xue T, Yang CG, Yang L, Ye M, Yeh M, Yeh YS, Yip K, Young BL, Yu ZY, Zhan L, Zhang C, Zhang FH, Zhang JW, Zhang QM, Zhang K, Zhang QX, Zhang SH, Zhang YC, Zhang YH, Zhang YX, Zhang ZJ, Zhang ZP, Zhang ZY, Zhao J, Zhao QW, Zhao YB, Zheng L, Zhong WL, Zhou L, Zhou ZY, Zhuang HL, and Zou JH
Abstract: The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ(13) with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GWth reactors were detected in six antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. With a 43,000 ton-GWth-day live-time exposure in 55 days, 10,416 (80,376) electron-antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to expected number of antineutrinos at the far hall is R=0.940±0.011(stat.)±0.004(syst.). A rate-only analysis finds sin(2)2θ(13)=0.092±0.016(stat.)±0.005(syst.) in a three-neutrino framework.
Published: 2012
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Publication Type

Journal

Database

Publisher

48 results on '"Hor, YK"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources