We report on the first results of a search for optical-wavelength photons mixing with hypothetical hidden-sector paraphotons in the mass range between 10^-5 and 10^-2 electron volts for a mixing parameter greater than 10^-7. This was a generation-regeneration experiment using the "light shining through a wall" technique in which regenerated photons are searched for downstream of an optical barrier that separates it from an upstream generation region. The new limits presented here are approximately three times more sensitive to this mixing than the best previous measurement. The present results indicate no evidence for photon-paraphoton mixing for the range of parameters investigated.
We propose a cavity experiment to search for low mass extra U(1) gauge bosons with gauge-kinetic mixing with the ordinary photon, so-called paraphotons. The setup consists of two microwave cavities shielded from each other. In one cavity, paraphotons are produced via photon-paraphoton oscillations. The second, resonant, cavity is then driven by the paraphotons that permeate the shielding and reconvert into photons. This setup resembles the classic ``light shining through a wall'' setup. However, the high quality factors achievable for microwave cavities and the good sensitivity of microwave de…
A search for paraphotons, or hidden U(1) gauge bosons, is performed using an intense X-ray beamline at SPring--8. "Light Shining through a Wall" technique is used in this search. No excess of events above background is observed. A stringent constraint is obtained on the photon--paraphoton mixing angle, $χ< 8.06\times 10^{-5}\ (95%\ {\rm C.L.})$ for $0.04\ {\rm eV}<m_{γ^{\prime}} < 26\ {\rm keV}$.
We present a scale invariant extension of the standard model with new QCD-like strong interaction in the hidden sector. A scale $Λ_H$ is dynamically generated in the hidden sector by dimensional transmutation, and chiral symmetry breaking occurs in the hidden sector. This scale is transmitted to the SM sector by a real singlet scalar messenger S, and can trigger electroweak symmetry breaking (EWSB). Thus all the mass scales in this model arises from the hidden sector scale $Λ_H$ which has quantum mechanical origin. Furthermore the lightest hadrons in the hidden sector is stable by the flavor c…
In order to significantly raise the mass of the supersymmetry Higgs boson, we consider a radiative correction to it by heavy (\sim 1 TeV) hidden sector fields, which communicate with the Higgs through relatively heavy "messengers" (300-500 GeV). The messenger fields (S, \bar{S}) are coupled to the Higgs ("y_HSH_uH_d," y_H\lesssim 0.7) and also to hidden sector fields with a Yukawa coupling of order unity. The hidden sector fields are assumed to be large representations of a hidden gauge group, and so their scalar partner masses can be heavier than other typical soft scalars in the visible sect…
We investigate a class of models where the supergravity model with the standard model gauge group is extended by a hidden sector $U(1)_X$ gauge group and where the lightest supersymmetric particle is the neutralino in the hidden sector. We investigate this possibility in a class of models where the stau is the lightest supersymmetric particle in the MSSM sector and the next-to-lightest supersymmetric particle of the $U(1)_X$-extended SUGRA model. In this case the stau will decay into the neutralino of the hidden sector. For the case when the mass gap between the stau and the hidden sector neut…
The presence of a hidden sector with very weak interactions with the standard model has significant implications on LHC signatures. In this work we discuss LHC phenomenology with the inclusion of a hidden sector by a $U(1)$ extension of MSSM/SUGRA. We consider both kinetic mixing and Stueckelberg mass mixing between the $U(1)$ gauge field of the hidden sector and $U(1)_Y$ of the visible sector. Such a model has an extended parameter space. We consider here two limited regions of this parameter space. In the first case we consider a $U(1)$ gauge field along with chiral fields needed for the Stu…
We demonstrate that rare decays of the Standard Model $Z$ boson can be used to discover and characterize the nature of new hidden-sector particles. We propose new searches for these particles in soft, high-multiplicity leptonic final states at the Large Hadron Collider. The proposed searches are sensitive to low-mass particles produced in $Z$ decays, and we argue that these striking signatures can shed light on the hidden-sector couplings and mechanism for mass generation.
In extended supersymmetric models with a hidden sector the lightest $R$-parity odd particle can reside in the hidden sector and act as dark matter. We consider the case when the hidden sector has ultraweak interactions with the visible sector. An interesting phenomenon arises if the LSP of the visible sector is charged in which case it will decay to the hidden sector dark matter. Due to the ultraweak interactions, the LSP of the visible sector will be long-lived decaying outside the detector after leaving a track inside. We investigate this possibility in the framework of a $U(1)_X$-extended M…
It is very likely that similar to the case of visible matter, dark matter too is composed of more than one stable component. In this work we investigate a two-component dark matter with one component from the visible sector and the other from the hidden sector. Specifically we consider a $U(1)_X$ hidden sector extension of MSSM/SUGRA where we allow for kinetic and Stueckelberg mass mixing between the two abelian $U(1)'s$, i.e., $U(1)_X$ and $U(1)_Y$. We further assume that the hidden sector has chiral matter which leads to a Dirac fermion as a candidate for dark matter. The lightest neutralino…
If hidden sector photons exist, they could be produced through oscillations of photons emitted by the Sun. We show that a search for these particles could be performed in Super-Kamiokande due to the presence in this detector of a large number of photomultiplier's (PMTs) with a relatively low noise and big size. These particles would penetrate the Earth shielding and would be detected by PMTs through their oscillations into real photons inside the PMTs vacuum volume. This would results in an increase of the PMT counting rate and it daily variations depending on the Earth position with respect t…
SOFTSUSY is a software designed to solve the RG equations of the MSSM and compute its low energy spectrum. HidSecSOFTSUSY is an extension of the SOFTSUSY package which modifies the beta functions to include contributions from light dynamic fields in the hidden sector.
We propose a scenario of gravity mediated supersymmetry breaking (gravity mediation) in a supersymmetric Randall-Sundrum model. In our setup, both of the visible sector and the hidden sector co-exist on the infrared (IR) brane. We introduce the Polonyi model as a simple hidden sector. Due to the warped metric, the effective cutoff scale on the IR brane is ``warped down'', so that the gravity mediation occurs at a low scale. As a result, the gravitino is naturally the lightest superpartner (LSP) and contact interactions between the hidden and the visible sector fields become stronger. We addres…
In this paper, we present the final results of our experiment on photon-axion oscillations in the presence of a magnetic field, which took place at LULI (Laboratoire pour l'Utilisation des Lasers Intenses, Palaiseau, France). Our null measurement allowed us to exclude the existence of axions with inverse coupling constant $M>9.\times 10^5$ GeV for low axion masses and to improve the preceding BFRT limits by a factor 3 or more for axion masses $1.1 {meV} <m_a<2.6 {meV}$. We also show that our experimental results improve the existing limits on the parameters of a low mass hidden-sector boson us…
If light hidden sector photons exist, they could be produced through kinetic mixing with solar photons in the eV energy range. We propose to search for this hypothetical hidden photon flux with the Super-Kamiokande and/or upgraded CAST detectors. The proposed experiments are sensitive to mixing strengths as small as 10^-9 for hidden photon masses in the sub eV region and, in the case of non-observation, would improve limits recently obtained from photon regeneration laser experiments in this mass region.
Resonant feedback circuits are proposed as an alternative to normal modes of conducting wall cavities or lumped circuits in searches for hidden sector particles. The proposed method offers several potential advantages over the most sensitive axion searches to date, that employ cavity resonators, including coverage of a wider range of axion masses, the ability to probe many axion masses simultaneously, and the elimination of experimentally troublesome mechanical tuning rod mechanisms. After an outline of the proposed method, we present a noise budget for a straw-man experiment configuration. We…
The flux of hypothetical "hidden photons" from the Sun is computed under the assumption that they interact with normal matter only through kinetic mixing with the ordinary standard model photon. Requiring that the exotic luminosity is smaller than the standard photon luminosity provides limits for the mixing parameter down to 10^-14, depending on the hidden photon mass. Furthermore, it is pointed out that helioscopes looking for solar axions are also very sensitive to hidden photons. The recent results of the CAST collaboration are used to further constrain the mixing parameter at low masses m…
In hidden sector models, dark matter does not directly couple to the particle content of the Standard Model, strongly suppressing rates at direct detection experiments, while still allowing for large signals from annihilation. In this paper, we conduct an extensive study of hidden sector dark matter, covering a wide range of dark matter spins, mediator spins, interaction diagrams, and annihilation final states, in each case determining whether the annihilations are s-wave (thus enabling efficient annihilation in the universe today). We then go on to consider a variety of portal interactions th…
The LHCb Collaboration has recently reported strong evidences of the existence of pentaquark states in the hidden-charm baryon sector, the so-called $P_c(4380)^+$ and $P_c(4450)^+$ signals. Five-quark bound states in the hidden-charm sector were explored by us using, for the quark-quark interaction, a chiral quark model which successfully explains meson and baryon phenomenology, from the light to the heavy quark sector. We extend herein such study but to the hidden-bottom pentaquark sector, analyzing possible bound-states with spin-parity quantum numbers $J^P=\frac12^\pm$, $\frac32^\pm$ and $\…
The hidden sector photon is a weakly interacting hypothetical particle with sub-eV mass that kinetically mixes with the photon. We describe a microwave frequency light shining through a wall experiment where a cryogenic resonant microwave cavity is used to try and detect photons that have passed through an impenetrable barrier, a process only possible via mixing with hidden sector photons. For a hidden sector photon mass of 53 $μ$eV we limit the hidden photon kinetic mixing parameter $χ< 1.7\times10^{-7}$, which is an order of magnitude lower than previous bounds derived from cavity experiment…
