Narrow Results

As the fundamental SU(2) supersymmetric parameters can be determined in the chargino sector, and the remaining fundamental parameters of the minimal supersymmetric extensions of the standard model can be analyzed in the neutralino sector, the two sectors can be correlated via these parameters. We have shown that for the CP-conserving case, the masses of all the neutralinos can be determined in terms of the chargino masses and tan β. In this case the neutralino masses are quite insensitive to the variations of tan β, they change by about 15% when tan β varies in the range from 5 to 50. In the CP-violating case, the neutralino masses are found to be quite sensitive to the variations of the CP-violating phase. For the heavier neutralinos the dependence of the masses to the CP-violating phase show complementary behavior at CP-violating points.

We suggest that the pseudo-scalar vacuum (PSV) field in the dark matter (DM) sector of the Universe may be as important as the electromagnetic vacuum field in the baryonic sector. In particular, the spin–spin interaction between the DM fermions, mediated by PSV, may represent the strongest interaction between the DM fermions due to the absence of the electric charge and the magnetic dipole moment. Based on this assumption, we consider the influence of the spin–spin interaction, mediated by PSV, on the spin precession of the DM fermions (e.g. neutralino). In the secular approximation, we obtain the exact expression describing the frequency of the precession and estimate the decoherence rate.

We present the prospects of searches for neutral, long-lived particles which decay to photons using their time of arrival measured with a newly installed EMTiming system at CDF. Using GMSB models we estimate the expected 95% confidence level exclusion regions as a function of the neutralino mass and lifetime. We find that a combination of single photon and diphoton analyses should allow the Tevatron in run II to easily extend the exclusion regions from ALEPH at LEP II, and cover parts of the theoretically favored GMSB parameter space.

The PAMELA satellite-borne experiment¹, to be launched in 2005, is a powerful spectrometer including a magnetic field tracker and particle identification detectors. PAMELA science is broad and includes studies of interstellar propagation, solar modulation and search for dark matter signals.

We studied the total variation of e⁺ and spectra due to the parameters uncertainties of propagation models and cross sections. We used B/C data and Galprop code and we derived also the uncertainty bands for subFe/Fe ratio, H and He. Finally we have considered a neutralino induced component in the mSUGRA framework and we have concluded that even for the model with diffusion and convection, where secondary spectra gives a good fit of the data, neutralino induced contribution can not be excluded up to now due to the overall uncertainties.

Astroparticle is a very wide, expanding, sector of Physics; this report covers only a fraction of it complementing the plenary reports of Y. Takahashi and K. Inoue. I will focus, in particular, on the experimental evidence of new physics, beyond the Standard Model. Astroparticle and accelerator experiments will give complementary tools in the search of new particles, like those of the dark matter, and new fundamental fields, like the inflaton.

Light neutralinos implemented in an effective Minimal Supersymmetric extension of the Standard Model at the electroweak scale without requirement of a gaugino-mass unification at a grand unification scale may have a mass around 10 GeV, i.e. in the range of interest for present data of direct search for dark matter particles in the galactic halo. In this talk we discuss the challenges and prospects of searching for them at the Large Hadron Collider.

It is described the distribution of small-scale dark matter (DM) clumps in the Galactic halo. These clumps are efficiently destructed by tidal forces at early stages of structure formation starting from time of clump detachment from the expansion of the Universe. Only a small fraction of these clumps survives the stage of hierarchical clustering. The survived clumps can be further destructed in the Galaxy by tidal interactions with stars in the Galactic bulge, disk and halo. It is shown that collective gravitational field of the Galactic disc provides the dominant contribution to the destruction of small-scale clumps. The resulting enhancement (boost factor) of annihilation signal due to the halo clumpiness strongly depends on the primordial perturbation spectrum and varies in the range 10-100.

IceCube is a kilometer scale high-energy neutrino observatory, currently under construction at the South Pole. It is a photo-detector, using the deep Antarctic ice as detection medium for the Cherenkov photons induced by relativistic charged particles. These charged particles may be atmospheric muons or reaction products from neutrino interactions in the vicinity of the instrumented volume. The experiment searches for neutrinos originating in astrophysical sources, and can also detect neutrinos from WIMP interaction in the Sun or Earth. In the last two austral summers, 9 in-ice strings and 16 surface IceTop stations (out of up to 80 planned) were successfully deployed, and the detector has been taking data ever since. In this proceedings, IceCube design, present status, performance and dark matter detection sensitivities will be discussed.

We review various issues related to the direct detection of constituents of dark matter, which are assumed to be Weakly Interacting Massive Particles (WIMPs). We specifically consider heavy WIMPs such as: 1) The lightest supersymmetric particle LSP or neutralino. 2) The lightest Kaluza-Klein particles in theories of extra dimensions and 3) other extensions of the standard model. In order to get the event rates one needs information about the structure of the nucleon as well as as the structure of the nucleus and the WIMP velocity distribution. These are also examined Since the expected event rates for detecting the recoiling nucleus are extremely low and the signal does not have a characteristic signature to discriminate against background we consider some additional aspects of the WIMP nucleus interaction, such as the periodic behavior of the rates due to the motion of Earth (modulation effect). Since, unfortunately, this is characterized by a small amplitude we consider other options such as directional experiments, which measure not only the energy of the recoiling nuclei but their direction as well. In these, albeit hard, experiments one can exploit two very characteristic signatures: a)large asymmetries and b) interesting modulation patterns. Furthermore we extended our study to include evaluation of the rates for other than recoil searches such as: i) Transitions to excited states, ii) Detection of recoiling electrons produced during the neutralino-nucleus interaction and iii) Observation of hard X-rays following the de-excitation of the ionized atom.

Astroparticle is a very wide, expanding, sector of Physics; this report covers only a fraction of it complementing the plenary reports of Y. Takahashi and K. Inoue. I will focus, in particular, on the experimental evidence of new physics, beyond the Standard Model. Astroparticle and accelerator experiments will give complementary tools in the search of new particles, like those of the dark matter, and new fundamental fields, like the inflaton.

The SUSY signals in the dominant stau-neutralino co-annihilation region at LHC are investigated. The region is consistent with the WMAP measurement of the cold dark matter relic density as well as all other current experimental bounds within the mSUGRA framework. The signals are characterized by an existence of very low-energy tau leptons in the final state due to small mass difference (ΔM) between and . We show that for ΔM = 9 GeV and with 30 fb^-1 of data, we can measure ΔM to 15% and to 6%.

This is not a review talk, but a tentative introduction to the subject. After a reminder of the Dark Matter problem, the main candidates are considered, especially focusing on the WIMPs (Neutralino) detection. Among the different types of detectors, the double-detection bolometers are particularly emphasized. After some model independent considerations, the procedure to extract physical results (exclusion plots or evidence of a signal) from the measured recoil energy spectra is described.

If non-baryonic dark matter exists in the form of neutralinos, a neutrino flux is expected from the decay of neutralino pair annihilation products inside heavy celestial bodies. Data taken with the AMANDA-II neutrino telescope located at the South Pole, have been used in a search for this indirect dark matter signal. Results are presented from searches for neutralinos accumulated in the Sun, using AMANDA-II data from 2001, and in the centre of the Earth, using AMANDA-II data from 2001 to 2003. Future perspectives, in view of higher statistics data samples acquired during recent years and by the combined AMANDA-IceCube detector, are also discussed.

If non-baryonic dark matter exists in the form of neutralinos, a neutrino flux is expected from the decay of neutralino pair annihilation products inside heavy celestial bodies. Data taken with the AMANDA (Antarctica Muon and Neutrino Detector Array) neutrino telescope located at the South Pole have been used in a search for this indirect dark matter signal. We present result from searches for neutralinos accumulated in the Sun and in the centre of the Earth, using the data taken up to 2003.

The IceCube neutrino detector is being deployed at the South Pole since 2006. This cubic kilometer observatory with 80 strings of 60 photomultipliers will be completed in 2011. The data taken in 2007 with 22 strings have been used in the search for neutrino signal from neutralinos in the Sun. Preliminary results of this analysis will be shown. The planned IceCube detector will be complemented with a dense inner core, Deep Core, to improve the sensitivity in the GeV-TeV energy domain. We will also discuss the expected performance of the combined IceCube - Deep Core detector in relation to dark matter searches.