26 research outputs found
Search for axioelectric effect of 5.5 MeV solar axions using BGO detectors
A search for axioelectric absorption of solar axions produced in the reactions has been performed
with a BGO detector placed in a low-background setup. A model-independent limit
on an axion-nucleon and axion-electron coupling constant has been obtained: for 90% confidence level. The
constrains of the axion-electron coupling have been obtained for hadronic axion
with masses in (0.1 - 1) MeV range: .Comment: 6 pages, 4 figures, to be published in EPJ C. arXiv admin note:
substantial text overlap with arXiv:1007.338
Search for solar axions produced by Compton process and bremsstrahlung using the resonant absorption and axioelectric effect
The search for resonant absorption of Compton and bremsstrahlung solar axions
by Tm nuclei have been performed. Such an absorption should lead to the
excitation of low-lying nuclear energy level: Tm Tm Tm (8.41 keV). Additionally the
axio-electric effect in silicon atoms is sought. The axions are detected using
a Si(Li) detectors placed in a low-background setup. As a result, a new model
independent restrictions on the axion-electron and the axion-nucleon coupling:
and the axion-electron
coupling constant: has been obtained. The
limits leads to the bounds 7.9 eV and 1.3 keV for the
mass of the axion in the DFSZ and KSVZ models, respectively ( C.L.).Comment: 6 pages, 3 figures, contributed to the 9th Patras Workshop on Axions,
WIMPs and WISPs, Mainz, June 24-28, 201
Constraints on the axion-electron coupling for solar axions produced by Compton process and bremsstrahlung
The search for solar axions produced by Compton () and bremsstrahlung-like () processes has
been performed. The axion flux in the both cases depends on the axion-electron
coupling constant. The resonant excitation of low-lying nuclear level of
was looked for: Tm Tm
Tm (8.41 keV). The Si(Li) detector and
Tm target installed inside the low-background setup were used to detect
8.41 keV -rays. As a result, a new model independent restriction on the
axion-electron and the axion-nucleon couplings was obtained:
. In model of hadronic
axion this restriction corresponds to the upper limit on the axion-electron
coupling and on the axion mass eV (90%
c.l.). The limits on axion mass are 105 eV and 1.3 keV for
DFSZ- and KSVZ-axion models, correspondingly (90% c.l.).Comment: 7 pages, 4 figure
Search for Solar Axions Produced in the Reaction
A search for the axioelectric absorption of 5.5-MeV solar axions produced in
the reaction was performed with
two BGO detectors placed inside a low-background setup. A model independent
limit on axion-photon and axion-nucleon couplings was obtained: . Constraints on the axion-electron
coupling constant were obtained for axions with masses in the MeV
range: . The solar positron flux from
decay was determined for axions with masses . Using the existing experimental data on the interplanetary positron
flux, a new constraint on the axion-electron coupling constant for axions with
masses in the MeV range was obtained: .Comment: 6 pages, 5 figure
Searches for axioelectric effect of solar axions with BGO-scintillator and BGO-bolometer detectors
A search for axioelectric absorption of 5.5 MeV solar axions produced in the
reaction has been
performed with a BGO detectors. A model-independent limit on the product of
axion-nucleon and axion-electron coupling constants has
been obtained: for 90\% C.L..Comment: 5 pages, 3 figures, Proceedings of the 10th Patras Workshop on
Axions, WIMPs and WISP 29 June - 4 July 2014, CERN, Geneva, Switzerlan
Recommended from our members
Search for Solar Axions Produced in Reaction with Borexino Detector
A search for 5.5-MeV solar axions produced in the reaction was performed using the Borexino detector. The Compton
conversion of axions to photons, ; the
axio-electric effect, ; the decay of axions into
two photons, ; and inverse Primakoff conversion on
nuclei, , are considered. Model independent
limits on axion-electron (), axion-photon (), and
isovector axion-nucleon () couplings are obtained: and at 1 MeV (90% c.l.). These limits are
2-4 orders of magnitude stronger than those obtained in previous
laboratory-based experiments using nuclear reactors and accelerators.Comment: 11 pages, 7 figures, submitted to Phys.Rev.
Recommended from our members
Measurement of geo-neutrinos from 1353 days of Borexino
We present a measurement of the geo--neutrino signal obtained from 1353 days
of data with the Borexino detector at Laboratori Nazionali del Gran Sasso in
Italy. With a fiducial exposure of (3.69 0.16) proton
year after all selection cuts and background subtraction, we detected
(14.3 4.4) geo-neutrino events assuming a fixed chondritic mass Th/U
ratio of 3.9. This corresponds to a geo-neutrino signal = (38.8
12.0) TNU with just a 6 probability for a null geo-neutrino
measurement. With U and Th left as free parameters in the fit, the relative
signals are = (10.6 12.7) TNU and =
(26.5 19.5) TNU. Borexino data alone are compatible with a mantle
geo--neutrino signal of (15.4 12.3) TNU, while a combined analysis with
the KamLAND data allows to extract a mantle signal of (14.1 8.1) TNU. Our
measurement of a reactor anti--neutrino signal =
84.5 TNU is in agreement with expectations in the presence of
neutrino oscillations.Comment: 9 pages, 6 figure
Borexino calibrations: Hardware, Methods, and Results
Borexino was the first experiment to detect solar neutrinos in real-time in
the sub-MeV region. In order to achieve high precision in the determination of
neutrino rates, the detector design includes an internal and an external
calibration system. This paper describes both calibration systems and the
calibration campaigns that were carried out in the period between 2008 and
2011. We discuss some of the results and show that the calibration procedures
preserved the radiopurity of the scintillator. The calibrations provided a
detailed understanding of the detector response and led to a significant
reduction of the systematic uncertainties in the Borexino measurements
Measurement of CNGS muon neutrino speed with Borexino
We have measured the speed of muon neutrinos with the Borexino detector using
short-bunch CNGS beams. The final result for the difference in time-of-flight
between a =17 GeV muon neutrino and a particle moving at the speed of light
in vacuum is {\delta}t = 0.8 \pm 0.7stat \pm 2.9sys ns, well consistent with
zero.Comment: 6 pages, 5 figure