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1.
《Physics of Atomic Nuclei》2006,69(11):1820-1828
An intense 37Ar source was produced by the (n, α) reaction on 40Ca by irradiating 330 kg of calcium oxide in the fast neutron breeder reactor at Zarechny, Russia. The 37Ar was released from the solid target by dissolution in acid, collected from this solution, purified, sealed into a small
source, and brought to the Baksan Neutrino Observatory, where it was used to irradiate 13 t of gallium metal in the Russian—American
solar neutrino experiment SAGE. Ten exposures of the gallium to the source, whose initial strength was ∼ 409 ± 2kCi, were
carried out during the period from April to September 2004. The 71Ge produced by the reaction 71Ga(ν
e, e
−)71Ge was extracted, purified, and counted. The measured production rate was 11.0
−0.9
+1.0
(stat.) ±0.6 (syst.) atoms of 71Ge/d, which is 0.79
−0.10
+0.09
of the theoretically calculated production rate.
The text was submitted by the authors in English. 相似文献
2.
A. V. Kopylov I. V. Orekhov V. V. Petukhov A. E. Solomatin 《Physics of Atomic Nuclei》2006,69(11):1829-1832
Experiments sensitive to pp neutrinos from the Sun are very promising for precise measurement of the mixing angle ϑ
12. A νe
− scattering experiment (XMASS) and/or a charged-current experiment (indium detector) can measure the flux of electron pp neutrinos. One can find the total flux of pp neutrinos from a luminosity constraint after the contributions of 7Be and CNO neutrinos to the total luminosity of the Sun are measured. A radiochemical experiment utilizing a lithium target
has high sensitivity to the CNO neutrinos; thus, it has a good promise for precise measurement of the mixing angle and for
a test of the current theory of evolution of the stars.
The text was submitted by the authors in English. 相似文献
3.
4.
A.E. Ball A. Braem L. Camilleri A. Catinaccio G. Chelkov F. Dydak A. Elagin P.K. Frandsen M. Gostkin A. Grant A. Guskov C. Joram Z. Krumshteyn H. Müller H. Postema M. Price T. Rovelli D. Schinzel J. Séguinot G. Valenti R. Voss J. Wotschack A. Zhemchugov 《The European Physical Journal C - Particles and Fields》2007,49(4):1117-1142
Today’s greatest challenge in accelerator-based neutrino physics is to measure the mixing angle θ13 which is known to be much smaller than the solar mixing angle θ12 and the atmospheric mixing angle θ23. A non-zero value of the angle θ13 is a prerequisite for observing CP violation in neutrino mixing. In this paper, we discuss a deep-sea neutrino experiment
with 1.5 Mt fiducial target mass in the Gulf of Taranto with the prime objective of measuring θ13. The detector is exposed to the CERN neutrino beam to Gran Sasso in off-axis geometry. Monochromatic muon neutrinos of ≈
800 MeV energy are the dominant beam component. Neutrinos are detected through quasi-elastic, charged-current reactions in
sea water; electrons and muons are detected in a large-surface, ring-imaging Cherenkov detector. The profile of the seabed
in the Gulf of Taranto allows for a moveable experiment at variable distances from CERN, starting at 1100 km. From the oscillatory
pattern of the disappearance of muon neutrinos, the experiment will measure sin2θ23 and especially Δm2
23 with high precision. The appearance of electron neutrinos will be observed with a sensitivity to P(νμ→νe) as small as 0.0035 (90% CL) and sin2θ13 as small as 0.0019 (90% CL; for a CP phase angle δ=0° and for normal neutrino mass hierarchy). 相似文献
5.
D S Narayan 《Pramana》1979,12(4):391-395
The production of prompt neutrinos in the beam dump experiment is explained in a cluster model, by postulating the emission
of strange clusters in hadron collisions, besides the usual non-strange clusters. The low mass strange clusters can decay
only by the weak interaction. The leptonic and semi-leptonic decay modes of these clusters give rise to prompt neutrinos.
A prediction of the model is that the ratios <v
e>/π
+ at PS energies would be the same as SPS energies. 相似文献
6.
M. Altmann F. v. Feilitzsch J. Hhne M. L. Sarsa J. Schnagl S. Wnninger 《Nuclear Physics B - Proceedings Supplements》1999,70(1-3)
An improvement of the statistical and systematic uncertainty beyond the level achieved in GALLEX is an essential prerequisite for GNO. As major contributions to these errors are associated with the detection of the EC-decay of 71Ge in miniaturized gas counters, low temperature calorimetric detectors might provide a promising alternative for a later phase of GNO. We report first results achieved in measurements of the EC-decaying isotopes 71Ge and 37Ar with cryogenic calorimeters. 相似文献
7.
O. G. Ryazhskaya 《Il Nuovo Cimento C》1995,18(1):77-80
Summary The background produced by isolated neutrons in Cherenkov detectors studying the atmospheric neutrinos is discussed. The neutrons
are generated in nuclear showers initiated by muons in the rock surrounding the detectors. It is shown that, taking into account
the detection of π0 events from reactions of nA→π0X, which look likev
e detection, results in an observedI(v
μ)/I(v
e) ratio close to the expected one for the energy range 0.2–5 GeV. 相似文献
8.
Yu. S. Lutostansky V. N. Tikhonov 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(4):476-480
The beta-decay strength function S
β(E) is described within two approaches: numerical solution of equation of the theory of finite Fermi systems for the effective
nuclear field and solution of these equations using the quasi-classical approximation. Calculations were carried out for the
isotopes 71Ge and 127Xe. A comparison with experimental data showed their good accuracy. The resonance structure of the function S
β(E) and the quenching-effect resulting from the effective charge of quasiparticles in the nucleus are discussed. 相似文献
9.
《The European Physical Journal A - Hadrons and Nuclei》2007,33(3):251-254
The FINUDA experiment studies the Λ -hypernuclei formation and decay using the reaction ( K
-
stop,π- induced by the low-momentum K- from the deacy of the φ -meson produced at the (e
+, e
- collider DAφ NE at the Laboratory Nazionali di Frascati of INFN. In this paper we present new data on the proton spectra
following the weak decay of 12
ΛC . 相似文献
10.
Cvavb Chandra Raju 《International Journal of Theoretical Physics》1997,36(12):2937-2951
The left-handed electron and muon neutrinos are considered to be Majorana neutrinos with equal mass. They have oppositeCP parities and are equivalent to a single Dirac neutrino. These neutrinos are shown to have a Majorana mass of about 6.5 eV.
The relatively large mass of their charged leptons is due to their γ5 coupling with the Higgs scalars By expressing the Higgs scalars as Clebsch-Gordon type of combinations ofZ andD neutral vector bosons with appropriate quantum numbers, it is shown that 2m
e
m
μ
/(m
e
2
+m
μ
2
)=(gv/g
A)
eμ
2
, whereg
v
andg
A
are the vector and axial vector coupling constants, respectively, ofZ (orD) with the leptonse and μ. Weinberg mixing parametersx
L
=e2/g
L
2
andx
R
=e
2/g
R
2
are determined to be 0.2254 and 0.2746, respectively. In the quark sector the Cabibbo angle is about 13°11′ and the masses
oft andb quarks are found to be respectively 134.2 and 4.69 GeV. 相似文献
11.
Marc Dixmier 《Pramana》1994,43(6):453-465
We suggest a new answer to the problem of the solar neutrinos: a neutrino-photon interaction that would cause the neutrinos
to disappear before they leave the sun or make them lose energy towards detection thresholds. We calculate the available energy
in the system of the centre of mass, and show that the photons may be endowed with a pseudo-cross-section in the system of
the sun. Under the assumption of an absorption, made to simplify the neutrino transport calculation, the chlorine experiment
yields:σ
a
=1.8(
−1.0
+0.7
)*10−9 barn, which is close tog
β/(ℏc)=4·49*10−9 barn. The escape probability is substantially larger for the gallium neutrinos than for the chlorine neutrinos. Thermal radiation
in the core of a supernova is suppressed by electrical conductivity, therefore the neutrinos from SN1987A could escape; they
interacted with the photon piston in the outer layers of the supernova and the interaction has to be a scattering. The cosmological
implications of a neutrino-photon interaction are discussed; Hubble’s constant may have to be modified. The case of an elastic
scattering between neutrino and photon is discussed in more detail.
An erratum to this article is available at . 相似文献
12.
《Zeitschrift fur Physik C Particles and Fields》1997,74(4):577-586
Data are presented on the reaction e+e? → γ + no other detected particle at centre-of-mass energies of 89.48, 91.26 and 93.08 GeV. The cross-section for this reaction is related directly to the number of light neutrino generations which couple to the Z° boson, and to several other possible phenomena such as the production of excited neutrinos, the production of any invisible ‘X’ particle, and the magnetic moment of the tau neutrino. Based on the observed number of single photon events, the number of light neutrinos that couple to the Z° is measured to be Nv = 2.89 ± 0.38. No evidence is found for anomalous production of energetic single photons, and upper limits at 95% confidence level are determined for excited neutrino production (BR < 4 ? 8 × 10?6 depending on its mass), production of an invisible ‘X’ particle (σ, < 0.1 pb for masses below 60 GeV), and the magnetic moment of the tau neutrino (< 5.1 × 10-6 μB). 相似文献
13.
《Physics of Atomic Nuclei》2004,67(6):1161-1171
The present status of the Baikal Neutrino Experiment and the present results of a search for upward going atmospheric neutrinos,
WIMPs, and magnetic monopoles obtained with the NT-200 detector are reviewed. The results of a search for very high-energy
neutrinos are presented as well. An upper limit on the ν
e
+ν
e
+ν
τ
neutrino diffuse flux of E
2Φ(E)<1.3×10−6 cm−2 s−1 sr−1 GeV within a neutrino energy range of 104–107 GeV is obtained, assumingan E
−2 behavior of the neutrino spectrum and a flavor ratio ν
e
:ν
π
:ν
τ
=1:1:1. We also describe the moderate upgrade of the NT-200 planned for the next few years and present a possible detector
on the Gigaton scale.
From Yadernaya Fizika, Vol. 67, No. 6, 2004, pp. 1186–1194.
Original English Text Copyright ? 2004 by Aynutdinov, Balkanov, Belolaptikov, Bezrukov, Budnev, Chensky, Chernov, Danilchenko,
Dzhilkibaev, Domogatsky, Dyachok, Gaponenko, O. Gress, T. Gress, Klabukov, Klimov, Klimushin, Konischev, Koshechkin, Kulepov,
Kuzmichev, Kuznetzov, Lubsandorzhiev, Mikheyev, Milenin, Mirgazov, Moiseiko, Osipova, Panfilov, G. Pan'kov, L. Pan'kov, Parfenov,
Pavlov, Pliskovsky, Pokhil, Polecshuk, Popova, Prosin, Rosanov, Rubtzov, Semeney, Shaibonov, Spiering, Streicher, Tarashansky,
Vasiliev, Vyatchin, Wischnewski, Yashin, Zhukov.
This article was submitted by the authors in English. 相似文献
14.
The technique of laser discrimination of 71Ge β-decay events in a radiochemical detector of low energy solar neutrinos is proposed and considered. This technique is based on laser selective photoionization of single Ga atom. Preliminary experiments are presented. 相似文献
15.
If neutrinos have non-vanishing mass and non-vanishing magnetic moments, then electron neutrinos emitted in nuclear reactions in the solar interior may undergo flavour oscillations, spin precession or resonant spin-flavour precession. Assuming equal values for the magnetic moments of all neutrino flavours and using the data from Homestake and SuperKamiokande we obtain an upper limit on the neutrino magnetic moment and find μνe ≤ (2.2 − 2.3) × 10−10μB, within four standard solar models. We also point out that this limit may be further reduced if the detector threshold energy for the νe,χe− scattering is decreased. 相似文献
16.
The analogues of the low-lying levels in71Ge have been observed as resonances in the compound nucleus71As through proton elastic scattering on70Ge in the energy rangeE
p=3.5 to 5.3 MeV. The excitation functions cover the analogue resonances corresponding to states upto 2.3 MeV excitation in71Ge. The sub-structures in the 5.06 MeV resonance, first observed by Temmer and co-workers have been confirmed in the present
experiment. The present investigation reveals similar sub-structures in the 4.13 MeV resonance lending further support to
the existence of intermediate structure near an isobaric analogue resonance. The resonance parameters and the spectroscopic
factors (for the corresponding parent states) have been extracted. The results are compared with the information available
from the70Ge(d, p)71Ge reaction. 相似文献
17.
Y. D. Kim 《Physics of Atomic Nuclei》2006,69(11):1970-1974
The XMASS project utilizes ultrapure liquid xenon and aims to detect pp and 7Be solar neutrinos by means of ν
e
e scattering. It requires low background and a low threshold, which will also enable us to search for dark matter in the Galactic
halo. By using a prototype detector, we have confirmed its feasibility to realize low background and low threshold. We have
estimated the sensitivity of an 800-kg liquid-xenon detector for a dark matter search experiment based on the experimental
results.
for the XMASS Collaboration
The text was submitted by the author in English. 相似文献
18.
Two metastable states of a multilayer Ge/p-Ge1−x
Six heterosystem with wide (∼ 35 nm) potential wells (Ge) are observed in strong magnetic fields B at low temperatures. In the first state, the Hall resistivity exhibits an inflection near the value ρxy=h/e
2 scaled to one Ge layer. The longitudinal magnetoresistivity ρxx(B) possesses a minimum in the range of fields where this inflection occurs. The temperature evolution of the inflection in
ρxy(B), the minimum of ρ xx(B), and the value of ρxy at the inflection indicates a weakly expressed state of the quantum Hall effect with a uniform current distribution over
the layers. In the second metastable state, an unusually wide plateau near h/2e
2 with a very weak field dependence is observed in ρxy(B). Estimates show that in these samples the Fermi level lies below but close to the top of the inflection in the bottom of
the well. For this reason, the second state can be explained by separation of a hole gas in the Ge layers into two sublayers,
and the saturation of ρxy(B) near h/2e
2 can be explained by the formation of a quantum Hall insulator state.
Pis’ma Zh. éksp. Teor. Fiz. 70, No. 4, 290–297 (25 August 1999) 相似文献
19.
G. Flik J. N. Bradbury D. W. Cooke R. H. Heffner M. Leon M. A. Paciotti M. E. Schillaci K. Maier H. Rempp C. Boekema J. J. Reidy H. Daniel 《Hyperfine Interactions》1986,32(1-4):595-600
In a recent experiment observing muon channeling from the decay of positive pions implanted in high-purity Ge single crystals,
the pion decay site is found to be sensitive to the concentration of excess charge carriers produced by photon absorption.
Distinctly different channeling profiles are observed in Ge at 100 K for illuminated samples (high carrier concentration)
as compared to unilluminated samples (low carrier concentration). From these data we conclude that different electronic states
of the pion in a semiconductor host lattice must account for the observed changes in the pion location. Furthermore we suggest
that the pion exists in the solid both as the bare entity π+ and as pionium (π+ e−), i.e., a hydrogen-like atom with a mesonic nucleus. 相似文献
20.
M. Aglietta P. Antonioli G. Badino M. Bertaina R. Bertoni A. Castellina A. Chiavassa W. Fulgione P. Galeotti P. Ghia A. Giuliano R. Granella C. Melagrana C. Morello G. Navarra L. Panaro L. Periale P. Picchi O. Saavedra G. C. Trinchero P. Vallania S. Vernetto C. Vigorito 《Il Nuovo Cimento C》1995,18(6):629-645
Summary The Large-Volume Detector (LVD) in the Gran Sasso underground Laboratory is a multipurpose detector consisting of a large
volume of liquid scintillator (at present 562 tons are in data taking) interleaved with limited-streamer tubes. Several physical
problems are investigated with LVD, the major being the search for neutrino bursts from gravitational stellar collapses in
our Galaxy. In this paper we discuss some results on cosmic neutrinos and cosmic-ray muons obtained with the first of the
five towers of LVD (operational since June 1992) and part of the second tower (operational since June 1994). The results of
the search for supernovae neutrinos show that LVD is a neutrino observatory able to detect neutrinos of different flavours
from gravitational stellar collapses in all our Galaxy, over a wide range of burst durations. Indeed, the carbon-based liquid-scintillator
target gives a unique possibility to directly detect neutral- and charged-currents neutrino interactions with a very good
signature. This characteristic of LVD allows us to make an indirect estimate of the neutrino rest mass and of neutrino oscillations
from supernovae in our Galaxy. No evidence for burst candidates has been found in the data recorded from June 1992 to March
1995, for a total live time of 682 days and a total exposure of 613 tons per year. We present the results of a time coincidence
analysis between low-energy signals, eventually due to neutrinos of different flavours, and γ-ray bursts (GRBs) detected by
the BATSE experiment. This search covers the period from June 1993 to March 1995, during which 41 GRBs have been selected
from the BATSE data. Since no excess of events in LVD has been found, upper limits on the neutrino fluxes are reported for
(νe, p), and for neutral- and charged-currents neutrino interactions of different flavours with the C-nuclei of the scintillator.
The muon intensity as a function of slant depth is presented. These measurements, obtained during a live time period of 11.556
hours, cover a slant depths range from about 3000 to about 20 000 hg/cm2 of standard rock and extend over five decades of intensity. An interesting result is that the muon flux is independent of
slant depth beyond a depth of about 14 000 hg/cm2 of standard rock, and corresponds to near horizontal muons. This is direct evidence that this flux is due to atmospheric
neutrinos interacting in the rock surrounding LVD. 相似文献