Search for Solar Axions Produced in the p+d→3He+Ap + d \rightarrow\rm{^3He}+ A Reaction

A search for the axioelectric absorption of 5.5-MeV solar axions produced in the $p+d\rightarrow \rm{^3He}+\gamma(5.5 \rm{MeV})$ 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: $|g_{Ae}\times g_{AN}| \leq 3.2\times 10^{-9} (m_A=0)$. Constraints on the axion-electron coupling constant were obtained for axions with masses in the $(0.1-1.0)$ MeV range: $g_{Ae}\leq (1.8-9.0)\times 10^{-7}$. The solar positron flux from $A\rightarrow e^-+e^+$ decay was determined for axions with masses $m_A > 2m_e$. 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 $(1.2-5.4)$ MeV range was obtained: $g_{Ae} \leq (1-5)\times 10^{-17}$.Comment: 6 pages, 5 figure

On a Light Spinless Particle Coupled to Photons

A pseudoscalar or scalar particle $\phi$ that couples to two photons but not to leptons, quarks and nucleons would have effects in most of the experiments searching for axions, since these are based on the $a \gamma \gamma$ coupling. We examine the laboratory, astrophysical and cosmological constraints on $\phi$ and study whether it may constitute a substantial part of the dark matter. We also generalize the $\phi$ interactions to possess $SU(2) \times U(1)$ gauge invariance, and analyze the phenomenological implications.Comment: LaTex, 20p., 6 figures. Changes in sections 4, 5 and figure 2, our bounds are now more stringent. To be published in Physical Review

Neutral Higgs bosons in the MNMSSM with explicit CP violation

Within the framework of the minimal non-minimal supersymmetric standard model (MNMSSM) with tadpole terms, CP violation effects in the Higgs sector are investigated at the one-loop level, where the radiative corrections from the loops of the quark and squarks of the third generation are taken into account. Assuming that the squark masses are not degenerate, the radiative corrections due to the stop and sbottom quarks give rise to CP phases, which trigger the CP violation explicitly in the Higgs sector of the MNMSSM. The masses, the branching ratios for dominant decay channels, and the total decay widths of the five neutral Higgs bosons in the MNMSSM are calculated in the presence of the explicit CP violation. The dependence of these quantities on the CP phases is quite recognizable, for given parameter values.Comment: 25 pages, 8 figure

The supersymmetric prediction for the muon transverse polarization in the K+←π0μ+νμK^+ \leftarrow \pi^0 \mu^+ \nu_\mu decay

The muon transverse polarization in the $K^+ \leftarrow \pi^0 \mu^+ \nu_\mu$ decay will be measured at the $10^{-4}$ level in forthcoming experiments. We compare the phenomenological perspectives with the theoretical predictions in supersymmetric extensions of the standard model. In the minimal extension, CP-violating phases lead to a non-zero transverse polarization, that however is too small to account for a positive experimental signal. The problems that one encounters when departing from minimal assumptions are discussed. An observable effect is possible if the hypothesis of R-parity conservation is relaxed, but only at the price of assuming a very special pattern for the R-parity breaking couplings.Comment: latex, 18 pages, 1 latex figur