1,721,000 research outputs found
Right-handed neutrino dark matter under the B − L gauge interaction
Get PDFWe study the right-handed neutrino (RHN) dark matter candidate in the minimal U(1)B−L gauge extension of the standard model. The U(1)B−L gauge symmetry offers three RHNs which can address the origin of the neutrino mass, the relic dark matter, and the matter-antimatter asymmetry of the universe. The lightest among the three is taken as the dark matter candidate, which is under the B − L gauge interaction. We investigate various scenarios for this dark matter candidate with the correct relic density by means of the freeze-out or freeze-in mechanism. A viable RHN dark matter mass lies in a wide range including keV to TeV scale. We emphasize the sub-electroweak scale light B − L gauge boson case, and identify the parameter region motivated from the dark matter physics, which can be tested with the planned experiments including the CERN SHiP experiment. © 2017, The Author(s)81111Nsciescopu
Gauge see-saw: A mechanism for a light gauge boson
Get PDFThere has been rapidly growing interest in the past decade in a new gauge boson which is considerably lighter than the standard model Z boson. A well-known example of this kind is the so-called dark photon, and it is actively searched for in various experiments nowadays. It would be puzzling to have a new gauge boson which is neither massless nor electroweak scale, but possesses a rather small yet nonzero mass. We present a mechanism that can provide a light gauge boson as a result of a mass matrix diagonalization
Mini force: The (B-L)+xY gauge interaction with a light mediator
No full textThe relevant phenomenology and the best search schemes of a subelectroweak-scale gauge boson can be vastly different depending on its coupling. For instance, the rare decay into a light gauge boson and the high precision parity test can be sensitive if it has an axial coupling. The minimal gauge extension of the standard model with the U(1)B-L+xY requires only three right-handed neutrinos, well suited to the current neutrino mass and mixing data, and no additional exotic matter fields. We study the light gauge boson of this symmetry in detail, including its axial coupling property from the hypercharge shift. © 2016 American Physical Society101011Nsciescopu
Dark photon relic dark matter production through the dark axion portal
Get PDFWe present a new mechanism to produce the dark photon (γ′) in the early Universe with the help of the axion (a) using a recently proposed dark axion portal. The dark photon, a light gauge boson in the dark sector, can be relic dark matter if its lifetime is long enough. The main process we consider is a variant of the Primakoff process fa→fγ′ mediated by a photon, which is possible with the axion-photon-dark photon coupling. The axion is thermalized in the early Universe because of the strong interaction and it can contribute to the nonthermal dark photon production through the dark axion portal coupling. It provides a two-component dark matter sector, and the relic density deficit issue of the axion dark matter can be addressed by the compensation with the dark photon. The dark photon dark matter can also address the reported 3.5 keV x-ray excess via the γ′→γa decay. © 2017 American Physical Society1111Nsciescopu
Constraints on the U(1)_L gauge boson in a wide mass range
No full textThere is a growing interest for the search of new light gauge bosons. The small mass of a new boson can turn various kinds of low-energy experiments to a new discovery machine, depending on their couplings to the Standard Model particles. It is important to understand the properties of each type of gauge boson and their current constraints for a given mass. While the dark photon (which couples to the electric charges) and the U(1)B−Lgauge boson have been well studied in an extensive mass range, theU(1)L gauge boson has not been fully investigated yet. We consider the gauge boson of the U(1)Lin a wide mass rangemZ′≈0–1012eV and investigate the constraints on its coupling from various experiments, discussing the similarities and differences from the dark photon and theU(1)B−Lgauge boson. (c) World Scientific Publishing Company11911Nsciescopu
Diphoton channel at the LHC experiments to find a hint for a new heavy gauge boson
No full textRecently there has been a buge interest in the diphoton excess around 750 GeV reported by both ATLAS and CMS collaborations, although the newest analysis with more statis-tics does not seem to support the excess. Nevertheless, the diphoton channel at the LHC experiments are a powerful tool to probe a new physics. One of the most natural explana-tions of a diphoton excess, if it occurs, could be a new scalar boson with exotic colored particles. In this setup, it would be legitimate to ask what is the role of this new scalar in nature. A heavy neutral gauge boson (Z′) is one of the traditional targets of the dis-covery at the collider experiments with numerous motivations. While the Landau-Yang theorem dictates the diphoton excess cannot be this spin-1 gauge boson, there is a strong correlation of a new heavy gauge boson and a new scalar boson which provides a mass to the gauge boson being at the same mass scale. In this paper, we point out a simple fact that a new scalar with a property similar th the recently highlighted 750GeV would suggest an existence of a TeV scale Z′ gauge boson that might be within the reach of the LHC Run 2 experiments. We take a scenario of the well-motivated and popular gauged B-L symmetry and require the gauge coupling unification to predict the mass and other properties of the Z′ and illustrate the discovery of the Z′ would during the LHC experiments.
(c) World Scientific Publishing Company3211Nsciescopu
Portal Connecting Dark Photons and Axions
Get PDFThe dark photon and the axion (or axionlike particle) are popular light particles of the hidden sector. Each of them has been actively searched for through the couplings called the vector portal and the axion portal. We introduce a new portal connecting the dark photon and the axion (axion-photon-dark photon, axion-dark photon-dark photon), which emerges in the presence of the two particles. This dark axion portal is genuinely new couplings, not just from a product of the vector portal and the axion portal, because of the internal structure of these couplings. We present a simple model that realizes the dark axion portal and discuss why it warrants a rich phenomenology. © 2017 American Physical Society8911Nsciescopu
Constraining Higgsino kink tracks from existing LHC searches
No full text Considering the supersymmetric model with the long-lived charged Higgsino, we discuss how Higgsino kink signals can show up in the latest LHC Disappearing Track (DT) and stable chargino searches. We derive constraints on the Higgsino kink signal, and characterize it in comparison to the Wino DT and the slepton kink track. We also discuss how to infer Higgsino model kinematics. </jats:p
Examining the origin of dark matter mass at colliders
Get PDFAs conventional dark matter scenarios have been probed extensively so far, the physics of a light dark matter charged under a new gauge group (dark gauge group) becomes one of new research avenues in many theoretical and experimental studies. We examine properties of a dark photon showering, the radiation process of light gauge bosons from energetic dark matter particles produced at the Large Hadron Collider (LHC). This showering process provides different signatures at the LHC depending on the property of dark matter under the dark gauge group. We show that the LHC experiment can identify the chirality of a dark matter, which leads to understanding the mass origin of particles in the dark sector. © 2018 authors. Published by the American Physical Society11Nsciescopu
- …
