Positronium portal into hidden sector: a new experiment to search for mirror dark matter

Abstract

The understanding of the origin of dark matter has great importance for cosmology and particle physics. Several interesting extensions of the standard model dealing with solution of this problem motivate the concept of hidden sectors consisting of SU (3) C × SU (2) L × U (1) Y singlet fields. Among these models, the mirror matter model is certainly one of the most interesting. The model explains the origin of parity violation in weak interactions, it could also explain the baryon asymmetry of the Universe and provide a natural ground for the explanation of dark matter. The mirror matter could have a portal to our world through photon-mirror photon mixing (ε). This mixing would lead to orthopositronium (o − Ps) to mirror orthopositronium oscillations, the experimental signature of which is the apparently invisible decay of o − Ps. In this paper, we describe an experiment to search for the decay o − Ps → invisible in vacuum by using a pulsed slow positron beam and a massive 4π BGO crystal calorimeter. The developed high efficiency positron tagging system, the low calorimeter energy threshold and high hermiticity allow the expected sensitivity in mixing strength to be ε ≃ 10 −9 , which is more than one order of magnitude below the current Big Bang Nucleosynthesis limit and in a region of parameter space of great theoretical and phenomenological interest. The vacuum experiment with such sensitivity is particularly timely in light of the recent DAMA/LIBRA observations of the annual modulation signal consistent with a mirror type dark matter interpretation.

Experimental limits on neutron disappearance into another braneworld

“…on a brane) values of the magnetic vector potentials. H cm leads to a phenomenology which shares some similarities with the mirror matter paradigm [6,[11][12][13] or other approaches involving some hidden or dark matter sectors [14]. Nevertheless the present approach differs in several ways:…”

“…Testing the existence of branes or extra dimensions is therefore becoming a fundamental challenge. Such evidences are expected to be obtained through high energy collisions [2][3][4], but it has been also demonstrated that some detectable effects could also be observed at low energy [2,3,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] . This is the topic of the present paper.…”

“…Since its value can be changed by modifying the local value of the magnetic vector potential, it can be consequently controlled by artificial means. The effects related to H cm [18,19] can be then distinguished from those related to coupling from other models [11,12].…”

“…Equation (12) shows that a resonant matter exchange between branes occurs whenever the magnetic vector potential rotates with an angular frequency ω = η. Of course, in this case, we do not consider an astrophysical field, and the rotative magnetic potential is supplied by an electromagnetic wave.…”

“…Other works also considered that fluctuations of our home-brane could yield small bubbles branes, which carry chargeless matter particles (such as neutrons for instance) into the bulk [3]. In another context, other approaches consider some coupling between certain particles of the standard model and some hidden or dark sectors [6,[8][9][10][11][12][13][14]. It is sometimes suspected that such hidden sectors could live in other branes.…”