Constraints on new interactions from neutron scattering experiments

Constraints for the constants of hypothetical Yukawa-type corrections to the Newtonian gravitational potential are obtained from analysis of neutron scattering experiments. Restrictions are obtained for the interaction range between 10⁻¹² and 10⁻⁷ cm, where Casimir force experiments and atomic-force microscopy are not sensitive. Experimental limits are obtained also for nonelectromagnetic inverse-power-law neutron-nucleus potentials. Some possibilities are discussed to strengthen these constraints. The text was submitted by the author in English.     

Constraints on four-Fermi contact interactions from low-energy electroweak experiments

We investigate the constraints on four-Fermi contact interactions from low-energy lepton-quark and lepton-lepton scattering experiments – polarization asymmetries in electron (muon)-nucleon scattering experiments, cesium and thallium atom parity violation measurements, neutrino-nuclei and neutrino-electron scattering experiments. These constraints are then combined by assuming the lepton and quark universalities and gauge invariance of the contact interaction, which leave independent six lepton-quark and three pure-leptonic interactions. Impacts of these constraints on models with an additional -boson are briefly discussed. We also present updates of the low-energy constraints on the and parameters. Received: 28 November 1997 / Published online: 26 February 1998     

Critical revision of the ZEPLIN-I sensitivity to WIMP interactions

The ZEPLIN Collaboration has recently published its first result presenting a maximum sensitivity of 1.1×¹⁰⁻⁶$1.1\times {10}^{\mathrm{-6}}$ picobarn for a WIMP mass of ≈60 GeV$\approx 60\text{ GeV}$. The analysis is based on a discrimination method using the different time distribution of scintillation light generated in electron recoil and nuclear recoil interactions. We show that the methodology followed both for the calibration of the ZEPLIN-I detector response and for the estimation of the discrimination power is not reliable enough to claim any background discrimination at the present stage. The ZEPLIN-I sensitivity appears then to be in the order of 10⁻³ picobarn, three orders of magnitude above the claimed 1.1×¹⁰⁻⁶$1.1\times {10}^{\mathrm{-6}}$ picobarn.     

Constraining WIMP magnetic moment from CDMS II experiment

We consider a degenerate or a nearly degenerate dark matter sector where a sizable magnetic moment of a (almost) Dirac type neutral dark matter candidate N is anticipated. Then, due to soft photon exchange, the cross-section in direct detection of N   can be enhanced at low Q²$Q^2$ region. We discuss the implication of this type of models in view of the recent CDMS II report.     

WIMP dark matter from gravitino decays and leptogenesis

The spontaneous breaking of B−L$B-L$ symmetry naturally accounts for the small observed neutrino masses via the seesaw mechanism. We have recently shown that the cosmological realization of B−L$B-L$ breaking in a supersymmetric theory can successfully generate the initial conditions of the hot early universe, i.e. entropy, baryon asymmetry and dark matter, if the gravitino is the lightest superparticle (LSP). This implies relations between neutrino and superparticle masses. Here we extend our analysis to the case of very heavy gravitinos which are motivated by hints for the Higgs boson at the LHC. We find that the nonthermal production of ‘pure’ wino or higgsino LSPs, i.e. weakly interacting massive particles (WIMPs), in heavy gravitino decays can account for the observed amount of dark matter while simultaneously fulfilling the constraints imposed by primordial nucleosynthesis and leptogenesis within a range of LSP, gravitino and neutrino masses. For instance, a mass of the lightest neutrino of 0.05 eV$0.05\text{eV}$ would require a higgsino mass below 900 GeV$900\text{GeV}$ and a gravitino mass of at least 10 TeV$10\text{TeV}$.     

Neutralino properties from a possible modulation signal in WIMP direct search

We report the main results of a paper by A. Bottino, F. Donato, N. Fornengo and S. Scopel, where the properties of neutralino are analysed under the hypothesis that some preliminary experimental results of the DAMA/NaI Collaboration may be indicative of a yearly modulation effect. The relevant supersymmetric configurations are analysed and the possibility of their investigation by indirect search for relic neutralinos and by accelerator measurements are discussed. It is shown that some of the configurations singled out by the DAMA/NaI results would have cosmological properties compatible with a neutralino as a dominant component of cold dark matter (on the average in the Universe and in our galactic halo).     

First experimental constraints on WIMP couplings in the effective field theory framework from CDEX

We present weakly interacting massive particles(WIMPs) search results performed using two approaches of effective field theory from the China Dark Matter Experiment(CDEX), based on the data from both CDEX-1B and CDEX-10 stages. In the nonrelativistic effective field theory approach, both time-integrated and annual modulation analyses were used to set new limits for the coupling of WIMP-nucleon effective operators at 90% confidence level(C.L.) and improve over the current bounds in the low mχregion. In the chiral effective field theory approach, data from CDEX-10 were used to set an upper limit on WIMP-pion coupling at 90% C.L. We for the first time extended the limit to the m_χ6 GeV/c~2 region.     

Constraints on neutron star radii based on chiral effective field theory interactions

We show that microscopic calculations based on chiral effective field theory interactions constrain the properties of neutron-rich matter below nuclear densities to a much higher degree than is reflected in commonly used equations of state. Combined with observed neutron star masses, our results lead to a radius R=9.7-13.9 km for a 1.4M⊙ star, where the theoretical range is due, in about equal amounts, to uncertainties in many-body forces and to the extrapolation to high densities.     

Constraints on SUSY models from LEP

We consider a particular supersymmetric extension of the standard model involving a light singlet and explainingM _Weak?M _Planck naturally, without detailed assumptions about a GUT or supergravity sector. Imposingm _cl>45 GeV for the lightest chargino andm _H1>20 GeV for the lightest Higgs scalar, the model survives all other constraints due to recent LEP results; it predicts, however, supersymmetric and Higgs particles to be seen in the near future.