Giorgio Gratta
Ray Lyman Wilbur Professor
Physics
Web page: http://grattalab3.stanford.edu/neutrino/index.html
Bio
Giorgio Gratta is a Professor of Physics at Stanford university and the current Physics department chair. Gratta is an experimentalist, with research interests in the broad area of the physics of fundamental particles and their interactions. While his career started with experiments at particle colliders, since at Stanford Gratta has tackled the study of neutrinos and gravity at the shortest distances.
With two landmark experiments using neutrinos produced by nuclear reactors, Gratta and collaborators investigated the phenomenon of neutrino flavor mixing, in one case reporting the first evidence for neutrino oscillations using artificial neutrinos. This established the finite nature of neutrino masses. The same experiment was also first to detect neutrinos from the interior of our planet, providing a new tool for the Earth sciences.
As a natural evolution from the discovery of neutrino oscillations, Gratta has led the development of liquid Xenon detectors in the search for the neutrinoless double beta decay, an exotic nuclear decay that, if observed, would change our understanding of the quantum nature of neutrinos and help explaining the asymmetry between matter and antimatter in the universe. Gratta is currently the scientific leader of one of the three very large experiments on the subject, world-wide.
In a rather different area of research, Gratta’s group is studying new long range interactions (or an anomalous behavior of gravity) at distances below 50 micrometers. This is achieved with an array of different techniques, from optical levitation of microscopic particles in vacuum, to the use of Mössbauer spectroscopy and, most recently, neutron scattering on nanostructured materials.
2024-25 Courses
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Independent Studies (3)
- Independent Research and Study
PHYSICS 190 (Aut, Win, Spr) - Research
PHYSICS 490 (Aut, Win, Spr) - Senior Thesis Research
PHYSICS 205 (Aut, Win, Spr)
- Independent Research and Study
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Prior Year Courses
2022-23 Courses
- Department Colloquium
PHYSICS 302 (Aut)
2021-22 Courses
- Quantum and Thermal Physics
PHYSICS 65 (Spr)
- Department Colloquium
Stanford Advisees
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Doctoral Dissertation Reader (AC)
Jadyn Anczarski, Jyotirmai Singh, Rachel Smith, Bahrudin Trbalic -
Postdoctoral Faculty Sponsor
Soud Al Kharusi, Evan Angelico, Lorenzo Magrini, Lin Si, Gautam Venugopalan, Marie Vidal, Yuqi Zhu -
Doctoral Dissertation Advisor (AC)
Clarke Hardy, Zhengruilong Wang -
Doctoral Dissertation Co-Advisor (AC)
Albert Nazeeri -
Postdoctoral Research Mentor
Evan Angelico, Lorenzo Magrini, Gautam Venugopalan, Marie Vidal
All Publications
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Neutrino physics for Korean diplomacy.
Science (New York, N.Y.)
2018; 362 (6415): 649–50
View details for PubMedID 30409877
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Single-beam dielectric-microsphere trapping with optical heterodyne detection
PHYSICAL REVIEW A
2018; 97 (1)
View details for DOI 10.1103/PhysRevA.97.013842
View details for Web of Science ID 000423426200014
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Magnetic bubble chambers and sub-GeV dark matter direct detection
PHYSICAL REVIEW D
2017; 95 (9)
View details for DOI 10.1103/PhysRevD.95.095001
View details for Web of Science ID 000400668700004
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Measurement of the drift velocity and transverse diffusion of electrons in liquid xenon with the EXO-200 detector
PHYSICAL REVIEW C
2017; 95 (2)
View details for DOI 10.1103/PhysRevC.95.025502
View details for Web of Science ID 000393852900005
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A density staggered cantilever for micron length gravity probing
IEEE. 2017: 1773–78
View details for DOI 10.1109/ECTC.2017.274
View details for Web of Science ID 000424702000256
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Search for Screened Interactions Associated with Dark Energy below the 100?µm Length Scale.
Physical review letters
2016; 117 (10): 101101-?
Abstract
We present the results of a search for unknown interactions that couple to mass between an optically levitated microsphere and a gold-coated silicon cantilever. The scale and geometry of the apparatus enable a search for new forces that appear at distances below 100 μm and which would have evaded previous searches due to screening mechanisms. The data are consistent with electrostatic backgrounds and place upper limits on the strength of new interactions at <0.1 fN in the geometry tested. For the specific example of a chameleon interaction with an inverse power law potential, these results exclude matter couplings β>5.6×10^{4} in the region of parameter space where the self-coupling Λ≳5 meV and the microspheres are not fully screened.
View details for DOI 10.1103/PhysRevLett.117.101101
View details for PubMedID 27636465
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An optimal energy estimator to reduce correlated noise for the EXO-200 light readout
JOURNAL OF INSTRUMENTATION
2016; 11
View details for DOI 10.1088/1748-0221/11/07/P07015
View details for Web of Science ID 000387763000006
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First search for Lorentz and CPT violation in double beta decay with EXO-200
PHYSICAL REVIEW D
2016; 93 (7)
View details for DOI 10.1103/PhysRevD.93.072001
View details for Web of Science ID 000373209600002
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Cosmogenic backgrounds to 0 nu beta beta in EXO-200
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
2016
View details for DOI 10.1088/1475-7516/2016/04/029
View details for Web of Science ID 000393286400003
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Search for 2 nu beta beta decay of Xe-136 to the 0(1)(+) excited state of Ba-136 with the EXO-200 liquid xenon detector
PHYSICAL REVIEW C
2016; 93 (3)
View details for DOI 10.1103/PhysRevC.93.035501
View details for Web of Science ID 000371740600008
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Testing long-distance modifications of gravity to 100 astronomical units
PHYSICAL REVIEW D
2015; 92 (10)
View details for DOI 10.1103/PhysRevD.92.104048
View details for Web of Science ID 000365512300007
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Measurements of the ion fraction and mobility of alpha- and beta-decay products in liquid xenon using the EXO-200 detector
PHYSICAL REVIEW C
2015; 92 (4)
View details for DOI 10.1103/PhysRevC.92.045504
View details for Web of Science ID 000363526000006
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Characterization of Silicon Photomultipliers for nEXO
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
2015; 62 (4): 1825-1836
View details for DOI 10.1109/TNS.2015.2453932
View details for Web of Science ID 000360016400017
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Investigation of radioactivity-induced backgrounds in EXO-200
PHYSICAL REVIEW C
2015; 92 (1)
View details for DOI 10.1103/PhysRevC.92.015503
View details for Web of Science ID 000358021500002
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An RF-only ion-funnel for extraction from high-pressure gases
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
2015; 379: 110-120
View details for DOI 10.1016/j.ijms.2015.01.003
View details for Web of Science ID 000353748100014
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Spectroscopy of Ba and Ba+ deposits in solid xenon for barium tagging in nEXO
PHYSICAL REVIEW A
2015; 91 (2)
View details for DOI 10.1103/PhysRevA.91.022505
View details for Web of Science ID 000349422200004
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A compact ultra-clean system for deploying radioactive sources inside the KamLAND detector
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2015; 769: 88-96
View details for DOI 10.1016/j.nima.2014.09.068
View details for Web of Science ID 000344997000015
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Laboratory studies on the removal of radon-born lead from KamLAND's organic liquid scintillator
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2015; 769: 79-87
View details for DOI 10.1016/j.nima.2014.09.050
View details for Web of Science ID 000344997000014
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Search for millicharged particles using optically levitated microspheres.
Physical review letters
2014; 113 (25): 251801-?
Abstract
We report results from a search for stable particles with charge ≳10^{-5}e in bulk matter using levitated dielectric microspheres in high vacuum. No evidence for such particles was found in a total sample of 1.4 ng, providing an upper limit on the abundance per nucleon of 2.5×10^{-14} at the 95% confidence level for the material tested. These results provide the first direct search for single particles with charge ≲0.1e bound in macroscopic quantities of matter and demonstrate the ability to perform sensitive force measurements using optically levitated microspheres in vacuum.
View details for PubMedID 25554874
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Search for Majoron-emitting modes of double-beta decay of Xe-136 with EXO-200
PHYSICAL REVIEW D
2014; 90 (9)
View details for DOI 10.1103/PhysRevD.90.092004
View details for Web of Science ID 000344917200002
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An apparatus to manipulate and identify individual Ba ions from bulk liquid Xe
REVIEW OF SCIENTIFIC INSTRUMENTS
2014; 85 (9)
Abstract
We describe a system to transport and identify barium ions produced in liquid xenon, as part of R&D towards the second phase of a double beta decay experiment, nEXO. The goal is to identify the Ba ion resulting from an extremely rare nuclear decay of the isotope (136)Xe, hence providing a confirmation of the occurrence of the decay. This is achieved through Resonance Ionization Spectroscopy (RIS). In the test setup described here, Ba ions can be produced in liquid xenon or vacuum and collected on a clean substrate. This substrate is then removed to an analysis chamber under vacuum, where laser-induced thermal desorption and RIS are used with time-of-flight mass spectroscopy for positive identification of the barium decay product.
View details for DOI 10.1063/1.4895646
View details for Web of Science ID 000342910500080
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Search for Majorana neutrinos with the first two years of EXO-200 data
NATURE
2014; 510 (7504): 229-234
Abstract
Many extensions of the standard model of particle physics suggest that neutrinos should be Majorana-type fermions-that is, that neutrinos are their own anti-particles-but this assumption is difficult to confirm. Observation of neutrinoless double-β decay (0νββ), a spontaneous transition that may occur in several candidate nuclei, would verify the Majorana nature of the neutrino and constrain the absolute scale of the neutrino mass spectrum. Recent searches carried out with (76)Ge (the GERDA experiment) and (136)Xe (the KamLAND-Zen and EXO (Enriched Xenon Observatory)-200 experiments) have established the lifetime of this decay to be longer than 10(25) years, corresponding to a limit on the neutrino mass of 0.2-0.4 electronvolts. Here we report new results from EXO-200 based on a large (136)Xe exposure that represents an almost fourfold increase from our earlier published data sets. We have improved the detector resolution and revised the data analysis. The half-life sensitivity we obtain is 1.9 × 10(25) years, an improvement by a factor of 2.7 on previous EXO-200 results. We find no statistically significant evidence for 0νββ decay and set a half-life limit of 1.1 × 10(25) years at the 90 per cent confidence level. The high sensitivity holds promise for further running of the EXO-200 detector and future 0νββ decay searches with an improved Xe-based experiment, nEXO.
View details for DOI 10.1038/nature13432
View details for Web of Science ID 000337032400042
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Improved measurement of the 2 nu beta beta half-life of Xe-136 with the EXO-200 detector
PHYSICAL REVIEW C
2014; 89 (1)
View details for DOI 10.1103/PhysRevC.89.015502
View details for Web of Science ID 000332158100004
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A setup for Ba-ion extraction from high pressure Xe gas for double-beta decay studies with EXO
16th International Conference on ElectroMagnetic Isotope Separators and Techniques Related to their Applications (EMIS)
ELSEVIER SCIENCE BV. 2013: 473–475
View details for DOI 10.1016/j.nimb.2013.05.086
View details for Web of Science ID 000329530400059
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Present Status and Future Perspectives for the EXO-200 Experiment
ADVANCES IN HIGH ENERGY PHYSICS
2013
View details for DOI 10.1155/2013/545431
View details for Web of Science ID 000327039900001
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Search for Neutrinoless Double-Beta Decay in Xe-136 with EXO-200
PHYSICAL REVIEW LETTERS
2012; 109 (3)
Abstract
We report on a search for neutrinoless double-beta decay of 136Xe with EXO-200. No signal is observed for an exposure of 32.5 kg yr, with a background of ∼1.5×10(-3) kg(-1) yr(-1) keV(-1) in the ±1σ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay T(1/2)(0νββ)(136Xe)>1.6×10(25) yr (90% C.L.), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation.
View details for DOI 10.1103/PhysRevLett.109.032505
View details for Web of Science ID 000306546300006
View details for PubMedID 22861843
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Xenon purity analysis for EXO-200 via mass spectrometry
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2012; 675: 40-46
View details for DOI 10.1016/j.nima.2012.01.066
View details for Web of Science ID 000302973600008
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The EXO-200 detector, part I: detector design and construction
JOURNAL OF INSTRUMENTATION
2012; 7
View details for DOI 10.1088/1748-0221/7/05/P05010
View details for Web of Science ID 000305419700030
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SEARCH FOR EXTRATERRESTRIAL ANTINEUTRINO SOURCES WITH THE KamLAND DETECTOR
ASTROPHYSICAL JOURNAL
2012; 745 (2)
View details for DOI 10.1088/0004-637X/745/2/193
View details for Web of Science ID 000300326800091
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A large Bradbury Nielsen ion gate with flexible wire spacing based on photo-etched stainless steel grids and its characterization applying symmetric and asymmetric potentials
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY
2012; 309: 97-103
View details for DOI 10.1016/j.ijms.2011.09.004
View details for Web of Science ID 000299063100013
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A xenon gas purity monitor for EXO
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2011; 659 (1): 215-228
View details for DOI 10.1016/j.nima.2011.09.017
View details for Web of Science ID 000297826100026
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Observation of Two-Neutrino Double-Beta Decay in Xe-136 with the EXO-200 Detector
PHYSICAL REVIEW LETTERS
2011; 107 (21)
Abstract
We report the observation of two-neutrino double-beta decay in (136)Xe with T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for (136)Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.
View details for DOI 10.1103/PhysRevLett.107.212501
View details for Web of Science ID 000297136700001
View details for PubMedID 22181874
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A magnetically driven piston pump for ultra-clean applications
REVIEW OF SCIENTIFIC INSTRUMENTS
2011; 82 (10)
Abstract
A magnetically driven piston pump for xenon gas recirculation is presented. The pump is designed to satisfy extreme purity and containment requirements, as is appropriate for the recirculation of isotopically enriched xenon through the purification system and large liquid xenon time projection chamber of EXO-200. The pump, using sprung polymer gaskets, is capable of pumping more than 16 standard liters per minute of xenon gas with 750 Torr differential pressure.
View details for DOI 10.1063/1.3653391
View details for Web of Science ID 000296531100064
View details for PubMedID 22047336
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Measurement of the B-8 solar neutrino flux with the KamLAND liquid scintillator detector
PHYSICAL REVIEW C
2011; 84 (3)
View details for DOI 10.1103/PhysRevC.84.035804
View details for Web of Science ID 000294925400002
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Partial radiogenic heat model for Earth revealed by geoneutrino measurements
NATURE GEOSCIENCE
2011; 4 (9): 647-651
View details for DOI 10.1038/ngeo1205
View details for Web of Science ID 000294452400016
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Constraints on theta(13) from a three-flavor oscillation analysis of reactor antineutrinos at KamLAND
PHYSICAL REVIEW D
2011; 83 (5)
View details for DOI 10.1103/PhysRevD.83.052002
View details for Web of Science ID 000288005500002
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A simple radionuclide-driven single-ion source
REVIEW OF SCIENTIFIC INSTRUMENTS
2010; 81 (11)
Abstract
We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating (148)Gd onto a silicon α-particle detector and vapor depositing a layer of BaF(2) over it. (144)Sm recoils from the alpha decay of (148)Gd are used to dislodge Ba(+) ions from the BaF(2) layer and emit them in the surrounding environment. The simultaneous detection of an α particle in the substrate detector allows for tagging of the nuclear decay and of the Ba(+) emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.
View details for DOI 10.1063/1.3499505
View details for Web of Science ID 000285006500010
View details for PubMedID 21133463
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Search for acoustic signals from ultrahigh energy neutrinos in 1500 km(3) of sea water
PHYSICAL REVIEW D
2010; 82 (7)
View details for DOI 10.1103/PhysRevD.82.073006
View details for Web of Science ID 000282812200003
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In search of no neutrinos
PHYSICS WORLD
2010; 23 (4): 27-30
View details for Web of Science ID 000277029600029
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Production of radioactive isotopes through cosmic muon spallation in KamLAND
PHYSICAL REVIEW C
2010; 81 (2)
View details for DOI 10.1103/PhysRevC.81.025807
View details for Web of Science ID 000278341300044
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Characterization of large area APDs for the EXO-200 detector
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2009; 608 (1): 68-75
View details for DOI 10.1016/j.nima.2009.06.029
View details for Web of Science ID 000269865500009
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Uncertainties in the anti-neutrino production at nuclear reactors
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS
2009; 36 (4)
View details for DOI 10.1088/0954-3899/36/4/045002
View details for Web of Science ID 000264386700002
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The KamLAND full-volume calibration system
JOURNAL OF INSTRUMENTATION
2009; 4
View details for DOI 10.1088/1748-0221/4/04/P04017
View details for Web of Science ID 000265878300017
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Oceanic ambient noise as a background to acoustic neutrino detection
PHYSICAL REVIEW D
2008; 78 (9)
View details for DOI 10.1103/PhysRevD.78.092001
View details for Web of Science ID 000261213900006
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Systematic study of trace radioactive impurities in candidate construction materials for EXO-200
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2008; 591 (3): 490-509
View details for DOI 10.1016/j.nima.2008.03.001
View details for Web of Science ID 000257819000008
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Precision measurement of neutrino oscillation parameters with KamLAND
PHYSICAL REVIEW LETTERS
2008; 100 (22)
Abstract
The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06.
View details for DOI 10.1103/PhysRevLett.100.221803
View details for Web of Science ID 000256528400011
View details for PubMedID 18643415
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A microfabricated sensor for thin dielectric layers
REVIEW OF SCIENTIFIC INSTRUMENTS
2008; 79 (4)
Abstract
We describe a sensor for the measurement of thin dielectric layers capable of operation in a variety of environments. The sensor is obtained by microfabricating a capacitor with interleaved aluminum fingers, exposed to the dielectric to be measured. In particular, the device can measure thin layers of solid frozen from a liquid or gaseous medium. Sensitivity to single atomic layers is achievable in many configurations and, by utilizing fast, high sensitivity capacitance readout in a feedback system onto environmental parameters; coatings of few layers can be dynamically maintained. We discuss the design, readout, and calibration of several versions of the device optimized in different ways. We specifically dwell on the case in which atomically thin solid xenon layers are grown and stabilized, in cryogenic conditions, from a liquid xenon bath.
View details for DOI 10.1063/1.2906402
View details for Web of Science ID 000255456800032
View details for PubMedID 18447546
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A linear RFQ ion trap for the enriched xenon observatory
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2007; 578 (2): 399-408
View details for DOI 10.1016/j.nima.2007.05.123
View details for Web of Science ID 000248930700005
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A liquid xenon ionization chamber in an all-fluoropolymer vessel
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2007; 578 (2): 409-420
View details for DOI 10.1016/j.nima.2007.05.259
View details for Web of Science ID 000248930700006
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Observation of single collisionally cooled trapped ions in a buffer gas
PHYSICAL REVIEW A
2007; 76 (2)
View details for DOI 10.1103/PhysRevA.76.023404
View details for Web of Science ID 000249154900087
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Search for the invisible decay of neutrons with KamLAND
PHYSICAL REVIEW LETTERS
2006; 96 (10)
Abstract
The Kamioka Liquid scintillator Anti-Neutrino Detector is used in a search for single neutron or two-neutron intranuclear disappearance that would produce holes in the -shell energy level of (12)C nuclei. Such holes could be created as a result of nucleon decay into invisible modes (inv), e.g., n--> 3v or nn--> 2v. The deexcitation of the corresponding daughter nucleus results in a sequence of space and time-correlated events observable in the liquid scintillator detector. We report on new limits for one- and two-neutron disappearance: tau(n--> inv) > 5.8 x 10(29) years and tau (nn--> inv) > 1.4 x 10(30) years at 90% C.L. These results represent an improvement of factors of approximately 3 and >10(4) and over previous experiments.
View details for DOI 10.1103/PhysRevLett.96.101802
View details for Web of Science ID 000236062800015
View details for PubMedID 16605724
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Mobility of thorium ions in liquid xenon
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
2005; 555 (1-2): 205-210
View details for DOI 10.1016/j.nima.2005.09.023
View details for Web of Science ID 000234354900023
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Experimental investigation of geologically produced antineutrinos with KamLAND
NATURE
2005; 436 (7050): 499-503
Abstract
The detection of electron antineutrinos produced by natural radioactivity in the Earth could yield important geophysical information. The Kamioka liquid scintillator antineutrino detector (KamLAND) has the sensitivity to detect electron antineutrinos produced by the decay of 238U and 232Th within the Earth. Earth composition models suggest that the radiogenic power from these isotope decays is 16 TW, approximately half of the total measured heat dissipation rate from the Earth. Here we present results from a search for geoneutrinos with KamLAND. Assuming a Th/U mass concentration ratio of 3.9, the 90 per cent confidence interval for the total number of geoneutrinos detected is 4.5 to 54.2. This result is consistent with the central value of 19 predicted by geophysical models. Although our present data have limited statistical power, they nevertheless provide by direct means an upper limit (60 TW) for the radiogenic power of U and Th in the Earth, a quantity that is currently poorly constrained.
View details for DOI 10.1038/nature03980
View details for Web of Science ID 000230788800050
View details for PubMedID 16049478
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Measurement of neutrino oscillation with KamLAND: Evidence of spectral distortion
PHYSICAL REVIEW LETTERS
2005; 94 (8)
Abstract
We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 nu (e) candidate events with energies above 3.4 MeV compared to 365.2+/-23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8+/-7.3 expected background events, the statistical significance for reactor nu (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from nu (e) oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2). A global analysis of data from KamLAND and solar-neutrino experiments yields Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2) and tan((2)theta=0.40(+0.10)(-0.07), the most precise determination to date.
View details for DOI 10.1103/PhysRevLett.94.081801
View details for Web of Science ID 000227386000009
View details for PubMedID 15783875
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Experimental study of acoustic ultra-high-energy neutrino detection
ASTROPHYSICAL JOURNAL
2005; 621 (1): 301-312
View details for Web of Science ID 000227406200028
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EXO: an advanced enriched xenon double-beta decay observatory
8th International Workshop on Topics in Astroparticle and Underground Physics
ELSEVIER SCIENCE BV. 2005: 224–226
View details for DOI 10.1016/j.nuclphysbps.2004.11.054
View details for Web of Science ID 000226845100054
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High sensitivity search for (nu)over-bar(e)'s from the Sun and other sources at KamLAND
PHYSICAL REVIEW LETTERS
2004; 92 (7)
Abstract
Data corresponding to a KamLAND detector exposure of 0.28 kton yr has been used to search for nu;(e)'s in the energy range 8.3
View details for DOI 10.1103/PhysRevLett.92.071301
View details for Web of Science ID 000189139500008
View details for PubMedID 14995837
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Correlated fluctuations between luminescence and ionization in liquid xenon
PHYSICAL REVIEW B
2003; 68 (5)
View details for DOI 10.1103/PhysRevB.68.054201
View details for Web of Science ID 000185240100039
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First results from KamLAND: Evidence for reactor antineutrino disappearance
PHYSICAL REVIEW LETTERS
2003; 90 (2)
Abstract
KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded.
View details for DOI 10.1103/PhysRevLett.90.021802
View details for Web of Science ID 000180444200007
View details for PubMedID 12570536
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Nuclear propelled vessels and neutrino oscillation experiments
PHYSICAL REVIEW LETTERS
2002; 89 (19)
Abstract
We study the effect of naval nuclear reactors on the study of neutrino oscillations. We find that the presence of naval reactors at unknown locations and times may limit the accuracy of future very long baseline reactor-based neutrino oscillation experiments. At the same time, we argue that a nuclear powered surface ship such as a large Russian icebreaker may provide an ideal source for precision experiments.
View details for DOI 10.1103/PhysRevLett.89.191802
View details for Web of Science ID 000178790900011
View details for PubMedID 12443112
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Sensitivity of an underwater acoustic array to ultra-high energy neutrinos
ASTROPARTICLE PHYSICS
2002; 17 (3): 279-292
View details for Web of Science ID 000176157700002
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Reactor-based neutrino oscillation experiments
REVIEWS OF MODERN PHYSICS
2002; 74 (2): 297-328
View details for Web of Science ID 000176677500001
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Nuclear reactor safeguards and monitoring with antineutrino detectors
JOURNAL OF APPLIED PHYSICS
2002; 91 (7): 4672-4676
View details for DOI 10.1063/1.1452775
View details for Web of Science ID 000174663900112
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Final results from the Palo Verde neutrino oscillation experiment
PHYSICAL REVIEW D
2001; 64 (11)
View details for DOI 10.1103/PhysRevD.64.112001
View details for Web of Science ID 000172450600004
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Predicting neutron production from cosmic-ray muons
PHYSICAL REVIEW D
2001; 64 (1)
View details for Web of Science ID 000169619300020
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Calibration of the L3 BGO calorimeter using an RFQ accelerator
8th Pisa Meeting on Advanced Detectors
ELSEVIER SCIENCE BV. 2001: 376–77
View details for Web of Science ID 000168567800099
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Search for neutrino oscillations at the Palo Verde nuclear reactors
XIXTH International Conference on neutrino Physics and Astrophysics
ELSEVIER SCIENCE BV. 2001: 91–98
View details for Web of Science ID 000166636700013
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Neutron production by cosmic-ray muons at shallow depth
PHYSICAL REVIEW D
2000; 62 (9)
View details for Web of Science ID 000165111400009
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Results from the Palo Verde neutrino oscillation experiment
PHYSICAL REVIEW D
2000; 62 (7)
View details for Web of Science ID 000089749400009
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New approach to background subtraction in low-energy neutrino experiments
PHYSICAL REVIEW D
2000; 62 (1)
View details for Web of Science ID 000087954100018
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Detection of very small neutrino masses in double-beta decay using laser tagging
PHYSICS LETTERS B
2000; 480 (1-2): 12-18
View details for Web of Science ID 000087121100003
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Neutrino oscillation experiments at nuclear reactors
6th Topical Seminar on Neutrino and Astroparticle Physics
ELSEVIER SCIENCE BV. 2000: 72–77
View details for Web of Science ID 000087016900011
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Search for neutrino oscillations at the Palo Verde nuclear reactors
PHYSICAL REVIEW LETTERS
2000; 84 (17): 3764-3767
View details for Web of Science ID 000086635900008
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Towards low-threshold, real-time solar neutrino detectors
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
1999; 438 (2-3): 317-321
View details for Web of Science ID 000084256800008
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The Palo Verde reactor neutrino oscillation experiment
18th International Conference on Neutrino Physics and Astrophysics (Neutrino 98)
ELSEVIER SCIENCE BV. 1999: 166–170
View details for Web of Science ID 000081497700024
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The Palo Verde reactor neutrino experiment a test for long baseline neutrino oscillations
5th International Workshop on Topics in Astroparticle and Underground Physics (TAUP 97)
ELSEVIER SCIENCE BV. 1999: 191–194
View details for Web of Science ID 000076059300032
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The Palo Verde neutrino oscillation experiment
XVI Workshop on Weak Interactions and Neutrinos (WIN 97)
ELSEVIER SCIENCE BV. 1998: 396–399
View details for Web of Science ID 000073147000072
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The Palo Verde reactor neutrino experiment - A test for long baseline neutrino oscillations
International School of Nuclear Physics - Neutrinos in Astro, Particle and Nuclear Physics
PERGAMON PRESS LTD. 1998: 253–262
View details for Web of Science ID 000074110000031
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Neutrino oscillation experiments at nuclear reactors
1st International Conference on Particle Physics Beyond the Standard Model
IOP PUBLISHING LTD. 1998: 945–955
View details for Web of Science ID 000081235100073
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A fast programmable trigger for pattern recognition
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
1997; 400 (2-3): 456-462
View details for Web of Science ID A1997YK07900024
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THE MARK-II SILICON STRIP VERTEX DETECTOR
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
1992; 313 (1-2): 63-102
View details for Web of Science ID A1992HG34300008
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MEASUREMENT OF THE BBAR FRACTION IN HADRONIC Z0 DECAYS WITH PRECISION VERTEX DETECTORS
PHYSICAL REVIEW LETTERS
1991; 67 (24): 3347-3350
View details for Web of Science ID A1991GT90000007
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THE MARK-II SILICON STRIP VERTEX DETECTOR AND PERFORMANCE OF A SILICON DETECTOR TELESCOPE IN THE MARK-II DETECTOR AT THE SLC
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
1991; 38 (1): 25-29
View details for Web of Science ID A1991ET82900006
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SEARCHES FOR SUPERSYMMETRIC PARTICLES PRODUCED IN Z-BOSON DECAY
PHYSICAL REVIEW LETTERS
1990; 64 (25): 2984-2987
View details for Web of Science ID A1990DJ50200006
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DIRECT SEARCH FOR PAIR PRODUCTION OF HEAVY STABLE CHARGED-PARTICLES IN Z-DECAYS
PHYSICAL REVIEW LETTERS
1990; 64 (25): 2980-2983
View details for Web of Science ID A1990DJ50200005
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SEARCH FOR NONMINIMAL NEUTRAL HIGGS BOSONS FROM Z-BOSON DECAYS
PHYSICAL REVIEW LETTERS
1990; 64 (24): 2881-2884
View details for Web of Science ID A1990DH37500012
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SEARCH FOR DOUBLY CHARGED HIGGS SCALARS IN Z-DECAY
PHYSICAL REVIEW LETTERS
1990; 64 (24): 2877-2880
View details for Web of Science ID A1990DH37500011
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MEASUREMENTS OF CHARGED-PARTICLE INCLUSIVE DISTRIBUTIONS IN HADRONIC DECAYS OF THE Z-BOSON
PHYSICAL REVIEW LETTERS
1990; 64 (12): 1334-1337
View details for Web of Science ID A1990CU42000006
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MEASUREMENT OF THE BBBAR FRACTION IN HADRONIC Z DECAYS
PHYSICAL REVIEW LETTERS
1990; 64 (11): 1211-1214
View details for Web of Science ID A1990CT09800007
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SEARCH FOR LONG-LIVED MASSIVE NEUTRINOS IN Z-DECAYS
PHYSICAL REVIEW LETTERS
1990; 64 (10): 1091-1094
View details for Web of Science ID A1990CQ97000006
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AN ALIGNMENT METHOD FOR THE MARK II SILICON STRIP VERTEX DETECTOR USING AN X-RAY-BEAM
5TH EUROPEAN SYMP ON SEMICONDUCTOR DETECTORS : NEW DEVELOPMENTS IN RADIATION DETECTORS
ELSEVIER SCIENCE BV. 1990: 257–64
View details for Web of Science ID A1990CR03600044
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DETERMINATION OF ALPHA-S FROM A DIFFERENTIAL-JET-MULTIPLICITY DISTRIBUTION IN E+E- COLLISIONS AT SQUARE-ROOT-S=29 AND 91 GEV
PHYSICAL REVIEW LETTERS
1990; 64 (9): 987-990
View details for Web of Science ID A1990CQ14100002
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MEASUREMENT OF Z DECAYS INTO LEPTON PAIRS
PHYSICAL REVIEW LETTERS
1989; 63 (26): 2780-2783
View details for Web of Science ID A1989CF65900003
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SEARCHES FOR NEW QUARKS AND LEPTONS PRODUCED IN Z-BOSON DECAY
PHYSICAL REVIEW LETTERS
1989; 63 (22): 2447-2451
View details for Web of Science ID A1989CA78000004
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MEASUREMENTS OF Z-BOSON RESONANCE PARAMETERS IN E+E- ANNIHILATION
PHYSICAL REVIEW LETTERS
1989; 63 (20): 2173-2176
View details for Web of Science ID A1989AY99800004
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1ST MEASUREMENTS OF HADRONIC DECAYS OF THE Z-BOSON
PHYSICAL REVIEW LETTERS
1989; 63 (15): 1558-1561
View details for Web of Science ID A1989AT77500005
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THE MARK-II DETECTOR FOR THE SLC
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
1989; 281 (1): 55-80
View details for Web of Science ID A1989AL05400008
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INITIAL MEASUREMENTS OF Z-BOSON RESONANCE PARAMETERS IN E+E- ANNIHILATION
PHYSICAL REVIEW LETTERS
1989; 63 (7): 724-727
View details for Web of Science ID A1989AK17500008
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STATUS OF THE SILICON STRIP VERTEX DETECTOR FOR THE MARK-II EXPERIMENT AT THE SLC
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
1988; 35 (1): 424-427
View details for Web of Science ID A1988N248100092
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RADIATION-DAMAGE STUDIES OF A CUSTOM-DESIGNED VLSI READOUT CHIP
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
1988; 35 (1): 166-170
View details for Web of Science ID A1988N248100034