A search for axioelectric absorption of 5.5 MeV solar axions produced in the $p + d rightarrow {^3rm{He}}+gamma~(5.5~ rm{MeV})$ reaction has been performed with a BGO detectors. A model-independent limit on the product of axion-nucleon $g_{AN}^3$ and axion-electron $g_{Ae}$ coupling constants has been obtained: $| g_{Ae}times g_{AN}^3|< 1.9times 10^{-10}$ for 90% C.L..
A search for axioelectric absorption of solar axions produced in the $ p + d rightarrow {^3rm{He}}+gamma~(5.5~ rm{MeV})$ 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: $| g_{Ae}times g_{AN}^3|< 1.9times 10^{-10}$ 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: $|g_{Ae}| leq (0.96 - 8.2)times 10^{-8}$.
The results of a search for solar axions from the Korea Invisible Mass Search (KIMS) experiment at the Yangyang Underground Laboratory are presented. Low-energy electron-recoil events would be produced by conversion of solar axions into electrons via the axio-electric effect in CsI(Tl) crystals. Using data from an exposure of 34,596 $rm kg cdot days$, we set a 90 % confidence level upper limit on the axion-electron coupling, $g_{ae}$, of $1.39 times 10^{-11}$ for an axion mass less than 1 keV/$rm c^2$. This limit is lower than the indirect solar neutrino bound, and fully excludes QCD axions heavier than 0.48 eV/$rm c^2$ and 140.9 eV/$rm c^2$ for the DFSZ and KSVZ models respectively.
We present the improved constraints on couplings of solar axions and more generic bosonic dark matter particles using 737.1 kg-days of data from the CDEX-1B experiment. The CDEX-1B experiment, located at the China Jinping Underground Laboratory, primarily aims at the direct detection of weakly interacting massive particles using a p-type point-contact germanium detector. We adopt the profile likelihood ratio method for analysis of data in the presence of backgrounds. An energy threshold of 160 eV was achieved, much better than the 475 eV of CDEX-1A with an exposure of 335.6 kg-days. This significantly improves the sensitivity for the bosonic dark matter below 0.8 keV among germanium detectors. Limits are also placed on the coupling $g_{Ae} < 2.48 times 10^{-11}$ from Compton, bremsstrahlung, atomic-recombination and de-excitation channels and $g^{eff}_{AN} times g_{Ae} < 4.14 times 10^{-17}$ from a $^{57}$Fe M1 transition at 90% confidence level.
BGO-OD is a newly commissioned experiment to investigate the internal structure of the nucleon, using an energy tagged bremsstrahlung photon beam at the ELSA electron facility. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. BGO-OD is ideal for investigating meson photoproduction. The extensive physics programme for open strangeness photoproduction is introduced, and preliminary analysis presented.
The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremsstrahlung photon beam to investigate the excitation structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. BGO-OD is ideal for investigating low momentum transfer processes due to the acceptance and high momentum resolution at forward angles. In particular, this enables the investigation of strangeness photoproduction where t-channel exchange mechanisms play an important role. This also allows access to low momentum exchange kinematics where extended, molecular structure may manifest in reaction mechanisms. First key results at low $t$ indicate a cusp-like structure in $K^+Sigma^0$ photoproduction at $W = 1900$,MeV, line shapes and differential cross sections for $K^+Lambda$(1405)$rightarrow K^+Sigma^0pi^0$, and a peak structure in $K^0_SSigma^0$ photoproduction. The peak in the $K^0_SSigma^0$ channel appears consistent with meson-baryon generated states, where equivalent models have been used to describe the $P_C$ pentaquark candidates in the heavy charmed quark sector.
V.N. Muratova
,A.V. Derbin
,L. Gironi
.
(2015)
.
"Searches for axioelectric effect of solar axions with BGO-scintillator and BGO-bolometer detectors"
.
Alexander Derbin
هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا