Search for solar axions with mass around 1 eV using coherent conversion of axions into photons

A search for solar axions has been performed using an axion helioscope which is equipped with a 2.3-m long 4 T superconducting magnet, a gas container to hold dispersion-matching gas, PIN-photodiode X-ray detectors, and a telescope mount mechanism to track the sun. A mass region around ma=1 eV$m_a=1\text{eV}$ was newly explored. From the absence of any evidence, analysis sets a limit on axion–photon coupling constant to be g_aγγ<5.6–13.4×¹⁰⁻¹⁰ GeV⁻¹$g_{a\gamma \gamma }<5.6\text{–}13.4\times {10}^{\mathrm{-10}}{\text{GeV}}^{\mathrm{-1}}$ for the axion mass of 0.84<ma<1.00 eV$0.84<m_a<1.00\text{eV}$ at 95% confidence level. It is the first result to search for the axion in the g_aγγ–ma$g_{a\gamma \gamma }\text{–}{m}_a$ parameter region of the preferred axion models with a magnetic helioscope.     

Search for solar hadronic axions produced by a bremsstrahlung-like process

We have searched for hadronic axions which may be produced in the Sun by a bremsstrahlung-like process, and observed in the HPGe detector by an axioelectric effect. A conservative upper limit on the hadronic axion mass of ma?334 eV$m_a?334\text{eV}$ at 95% C.L. is obtained. Our experimental approach is based on the axion–electron coupling and it does not include the axion–nucleon coupling, which suffers from the large uncertainties related to the estimation of the flavor-singlet axial-vector matrix element.     

Search for resonant absorption of solar axions by atomic nuclei

Search for resonant absorption of solar axions by ⁵⁷Fe and ¹⁶⁹Tm nuclei, leading to the excitation of the first nuclear level: ⁵⁷Fe: A + ⁵⁷Fe → ⁵⁷Fe* → ⁵⁷Fe + γ and A + ¹⁶⁹Tm → ¹⁶⁹Tm* → ¹⁶⁹Tm + γ, has been performed. To this end, the energy spectra of the Si(Li) detector with ⁵⁷Fe and ¹⁶⁹Tm targets have been measured. The detector and targets were located in a low-background setup equipped with passive and active shields. A new upper limit on the axion mass: m _A ≤ 330 eV (90% confidence level) has been established from the spectrum of ⁵⁷Fe (30 days). Measurements with a ¹⁶⁹Tm target during 8 days gave a new upper limit on the product of the axion-photon coupling constant and the axion mass: g _Aγ (GeV^?1) × m _A (eV) ≤ 2.9 × 10^?4 (90% confidence level).     

Search for solar axions generated by the Primakoff effect with resonance absorption by <Superscript>169</Superscript>Tm

We searched for resonant excitation of the first excited state of the ¹⁶⁹Tm nucleus by axions formed inside the Sun by the Primakoff effect, A + ¹⁶⁹Tm → ¹⁶⁹Tm* → ¹⁶⁹Tm + γ (8.41keV). Gamma quanta with an energy of 8.41keV were registered by a sectionalized Si(Li) detector installed in a low-background setup. As a result, we set a new upper limit for the photon to axion coupling constant, g _Aγ (GeV⁻¹)m _A (eV) ≤ 1.06 × 10⁻⁵, which for a hadronic axion model corresponds to a mass limit of m _A ≤ 169 eV at a 90% confidence level.     

Second generation solar adaptive optics for 1-m New Vacuum Solar Telescope at the Fuxian Solar Observatory

A second generation solar adaptive optics(AO) system is built and installed at the 1-m New Vacuum Solar Telescope(NVST) of the Fuxian Solar Observatory(FSO) in 2015. The AO high-order correction system consists of a 151-element deformable mirror(DM), a correlating Shack–Hartmann(SH) wavefront sensor(WFS)with a 3500 Hz frame rate, and a real-time controller. The system saw first light on Mar. 16, 2015. The simultaneous high-resolution photosphere and chromosphere images with AO are obtained. The on-sky observational results show that the contrast and resolution of the images are apparently improved after the wavefront correction by AO.     

Search for weakly interacting sub-eV particles with the OSQAR laser-based experiment: results and perspectives

Recent Planck measurements show some CMB anomalies on large angular scales, which confirms the early observations by WMAP. We show that an inflationary model, in which before the slow-roll inflation the Universe is in a superinflationary phase, can generate a large-scale cutoff in the primordial power spectrum, which may account for not only the power suppression on large angular scales, but also a large dipole power asymmetry in the CMB. We discuss an implementation of our model in string theory.     

Search for solar axions emitted in the M1-transition of 7Li* with Borexino CTF

Results of background measurements with a prototype of the Borexino detector were used to search for 478 keV solar axions emitted in the M1-transitions of ⁷Li^*. The Compton conversion of axion to a photon A+e→e+γ, axioelectric effect A+e+Z→e+Z, decay of axion in two photons A→2γ and Primakoff conversion on nuclei A+Z→γ+Z are considered. The upper limit on constants of interaction of axion with electrons, photons and nucleons – g_Aeg_AN≤(1.0–2.4)×10^-10 at m_A≤450 keV and g_Aγg_AN≤5×10^-9 GeV^-1 at m_A≤10 keV are obtained (90%c.l.). For heavy axions with mass at 100<m_A<400 keV the limits g_Ae<(0.7–2.0)×10^-8 and g_Aγ<10^-9–10^-8 are obtained in assumption that g_AN depends on m_A as for KSVZ axion model. These limits are stronger than obtained in previous laboratory-based experiments using nuclear reactor and artificial radioactive sources. PACS 14.80.Mz; 29.40.Mc; 26.65.+t     

Search for High-Energy Neutrinos from GW170817 with the Baikal-GVD Neutrino Telescope

JETP Letters - The Advanced Laser Interferometer Gravitational-Wave Observatory and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short...     

High nuclear polarization in3He and3He-4He gas mixtures by optical pumping with a laser diode

New diode lasers delivering 50 mW output power at 1083 nm are shown to be efficient sources for optical pumping of helium. They can polarize nuclei in a³He gas up toM = 50% over the pressure range 0.4–1.6 torr. Larger nuclear polarizationsM of³He nuclei, of order 80%, can be obtained in³He-⁴He mixtures when the laser frequency is tuned to a⁴He line. A standard optical measurement of nuclear polarizationM has been extended to the case of³He-⁴He mixtures. The effect of various parameters on the steady-state polarizationM and on the pumping timeT _p is discussed.Laboratoire associé au Centre National de la Recherche Scientifique et à l'Université P. M. Curie     

Polarization analysis of the light emitted by an optically pumped3He gas

Optical measurements of the nuclear polarizationM of an optically pumped pure³He gas have been performed. They consist in monitoring the circular polarization of various helium lines emitted by the discharge. We have demonstrated the possibility to use the orange line (587.5 nm) to measureM and we have calibrated this technique over the pressure range 0.4–6.5 Torr. The circular polarization of the light has been analyzed using a new device which includes a static polarimeter and photodiodes as light sensors. The intensity of the discharge was modulated and the detection was made at the frequency of modulation.Laboratoire associé au Centre National de la Recherche Scientifique et a l'Université P. M. Curie     

Search for isovector giant monopole resonances via the Pb(3He,tp) reaction

The (nat)Pb(3He,tp) reaction at E(3He) = 177 MeV was studied to identify 2Planck's over 2piomega isovector monopole strength in Bi isotopes. Monopole strength was found in the region -45相似文献   

Search for intermediate mass magnetic monopoles and nuclearites with the SLIM experiment

SLIM is a large area experiment (440 m²) installed at the Chacaltaya cosmic ray laboratory since 2001, and about 100 m² at Koksil, Himalaya, since 2003. It is devoted to the search for intermediate mass magnetic monopoles (10⁷–10¹³ GeV/c²) and nuclearites in the cosmic radiation using stacks of CR-39 and Makrofol nuclear track detectors. In four years of operation it will reach a sensitivity to a flux of about 10^-15 cm^-2 s^-1 sr^-1. We present the results of the calibration of CR-39 and Makrofol and the analysis of a first sample of the exposed detector.     

Power enhancement of the cw 12.08 μm NH3 Raman laser with the addition of H2/He buffer gases

The effects of H₂, He, and N₂ buffer gases on the efficiency of the cw 12.08 μm NH₃ Raman laser are studied experimentally. The laser output power is increased by nearly 60% with the addition of H₂ or He, which we essentially attribute to the high thermal conductivity of these buffer gases. In the optimum conditions (NH₃/H₂:1/1 mixture with 0.35 Torr partial pressure of NH₃) 3.3 W output power at 12.08 μm is obtained which corresponds to 11% power conversion efficiency.