Reconciling the positive DAMA annual modulation signal with the negative results of the CDMS II experiment

We examine the recent CDMS II results in the context of the mirror matter interpretation of the DAMA/NaI experiment.We find that the favoured mirror matter interpretation of the DAMA/NaI experiment -- a $He'/H'$ dominated halo with a small $O'$ component is fully consistent with the null results reported by CDMS II. While the CDMS II experiment is quite sensitive to a heavy $Fe'$ component, and may yet find a positive result, a more decisive test of mirror matter-type dark matter would require a lower threshold experiment using light target elements.Comment: about 6 page

Have mirror micrometeorites been detected?

Slow-moving ($v \sim 15$ km/s) 'dark matter particles' have allegedly been discovered in a recent experiment. We explore the possibility that these slow moving dark matter particles are small mirror matter dust particles originating from our solar system. Ways of further testing our hypothesis, including the possibility of observing these dust particles in cryogenic detectors such as NAUTILUS, are also discussed.Comment: Few changes, about 8 pages lon

Natural electroweak symmetry breaking in generalised mirror matter models

It has recently been pointed out that the mirror or twin Higgs model is more technically natural than the standard model, thus alleviating the ``little'' hierarchy problem. In this paper we generalise the analysis to models with an arbitrary number of isomorphic standard model sectors, and demonstrate that technical naturalness increases with the number of additional sectors. We consider two kinds of models. The first has $N$ standard model sectors symmetric under arbitrary permutations thereof. The second has $p$ left-chiral standard model sectors and $p$ right-chiral or mirror standard model sectors, with $p$-fold permutation symmetries within both and a discrete parity transformation interchanging left and right. In both kinds of models the lightest scalar has an invisible width fraction 1/N, which will provide an important means of experimentally testing this class of models.Comment: about 8 page

A CoGeNT confirmation of the DAMA signal

The CoGeNT collaboration has recently reported a rising low energy spectrum in their ultra low noise germanium detector. This is particularly interesting as the energy range probed by CoGeNT overlaps with the energy region in which DAMA has observed their annual modulation signal. We show that the mirror dark matter candidate can simultaneously explain both the DAMA annual modulation signal and the rising low energy spectrum observed by CoGeNT. This constitutes a model dependent confirmation of the DAMA signal and adds weight to the mirror dark matter paradigm.Comment: About 8 pages, expanded and update

Maximal νe\nu_e oscillations, Borexino and smoking guns

We examine the maximal $\nu_e --> \nu_s$ and $\nu_e --> \nu_\mu,\tau$ oscillation solutions to the solar neutrino problem. These solutions lead to roughly a 50% solar flux reduction for the large parameter range $3\times 10^{-10} < \delta m^2/eV^2 < 10^{-3}$. It is known that the earth regeneration effect may cause a potentially large night-day asymmetry even for maximal neutrino oscillations. We investigate the night-day asymmetry predictions for the forthcoming Borexino measurement of the ^7Be neutrinos for both maximal $\nu_e --> \nu_s$ and $\nu_e --> \nu_\mu,\tau$ oscillations. If $y \times 10^{-8} \nu_s$ case and y = 1 for $\nu_e --> \nu_\mu,\tau$ case) then the maximal neutrino oscillations will lead to observable night-day asymmetries in Borexino and/or superKamiokande. With Kamland covering the high mass range, $10^{-5} < \delta m^2/eV^2 < 10^{-3}$ and Borexino/superK covering the low mass range, $3\times 10^{-10} < \delta m^2/eV^2 < 5\times 10^{-9}$ ("just so" region), essentially all of the $\delta m^2$ parameter space will soon be scrutinized.Comment: Various improvements...still about 6 pages with some fig

Generalized mirror matter models

Non-minimal gauge models with exact unbroken improper space-time symmetries are constructed and their cosmological and astrophysical implications explored.Comment: about 5 page

Mirror and hidden sector dark matter in the light of new CoGeNT data

The CoGeNT collaboration has recently made available new data collected over a period of 15 months. In addition to more accurately measuring the spectrum of nuclear recoil candidate events they have announced evidence for an annual modulation signal. We examine the implications of these new results within the context of mirror/hidden sector dark matter models. We find that the new CoGeNT data can be explained within this framework with parameter space consistent with the DAMA annual modulation signal, and the null results of the other experiments. We also point out that the CoGeNT spectrum at low energies is observed to obey $dR/dE_R \propto 1/E_R^2$ which suggests that dark matter interacts via Rutherford scattering rather than the more commonly assumed contact (four-fermion) interaction.Comment: About 12 pages, matches published versio

Detecting dark matter using centrifuging techniques

A new and inexpensive technique for detecting self interacting dark matter in the form of small grains in bulk matter is proposed. Depending on the interactions with ordinary matter, dark matter grains in bulk matter may be isolated by using a centrifuge and using ordinary matter as a filter. The case of mirror matter interacting with ordinary matter via photon-mirror photon kinetic mixing provides a concrete example of this type of dark matter candidate.Comment: About 9 page

Shielding of a direct detection experiment and implications for the DAMA annual modulation signal

Previous work has argued that, in the framework of plasma dark matter models, the DAMA annual modulation signal can be consistently explained with electron recoils. In the specific case of mirror dark matter, that explanation requires an effective low velocity cutoff, $v_c \gtrsim 30,000$ km/s, for the halo mirror electron distribution at the detector. We show here that this cutoff can result from collisional shielding of the detector from the halo wind due to Earth-bound dark matter. We also show that shielding effects can reconcile the kinetic mixing parameter value inferred from direct detection experiments with the value favoured from small scale structure considerations, $\epsilon \approx 2 \times 10^{-10}$.Comment: 10 page