Beyond Minimal Lepton-flavored Dark Matter
Beyond Minimal Lepton-flavored Dark Matter

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Published: 2016

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ISBN-13:

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In this paper, we consider a class of flavored dark matter (DM) theories where dark matter interacts with the Standard Model lepton fields at the renormalizable level. We allow for a general coupling matrix between the dark matter and leptons whose structure is beyond the one permitted by the minimal flavor violation (MFV) assumption. It is assumed that this is the only new source of flavor violation in addition to the Standard Model (SM) Yukawa interactions. The setup can be described by augmenting the SM flavor symmetry by an additional SU(3)[chi], under which the dark matter [chi] transforms. This framework is especially phenomenologically rich, due to possible novel flavor-changing interactions which are not present within the more restrictive MFV framework. As a representative case study of this setting, which we call "beyond MFV" (BMFV), we consider Dirac fermion dark matter which transforms as a singlet under the SM gauge group and a triplet under SU(3)[chi]. The DM fermion couples to the SM lepton sector through a scalar mediator [Phi]. Unlike the case of quark-flavored DM, we show that there is no Z3 symmetry within either the MFV or BMFV settings which automatically stabilizes the lepton-flavored DM. We discuss constraints on this setup from flavor-changing processes, DM relic abundance as well as direct and indirect detections. We find that relatively large flavor-changing couplings are possible, while the dark matter mass is still within the phenomenologically interesting region below the TeV scale. Collider signatures which can be potentially searched for at the lepton and hadron colliders are discussed. Finally, we discuss the implications for decaying dark matter, which can appear if an additional stabilizing symmetry is not imposed.

Flavored Dark Matter Beyond Minimal Flavor Violation
Flavored Dark Matter Beyond Minimal Flavor Violation

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Publisher:

Published: 2014

Total Pages: 118

ISBN-13:

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We study the interplay of flavor and dark matter phenomenology for models of flavored dark matter interacting with quarks. We allow an arbitrary flavor structure in the coupling of dark matter with quarks. This coupling is assumed to be the only new source of violation of the Standard Model flavor symmetry extended by a U(3)x associated with the dark matter. We call this ansatz Dark Minimal Flavor Violation (DMFV) and highlight its various implications, including an unbroken discrete symmetry that can stabilize the dark matter. As an illustration we study a Dirac fermionic dark matter [chi] which transforms as triplet under U(3)x, and is a singlet under the Standard Model. The dark matter couples to right-handed down-type quarks via a colored scalar mediator [Phi] with a coupling [lambda]. We identify a number of "flavor-safe" scenarios for the structure of [lambda] which are beyond Minimal Flavor Violation. For dark matter and collider phenomenology we focus on the well-motivated case of b-flavored dark matter. The combined flavor and dark matter constraints on the parameter space of [lambda] turn out to be interesting intersections of the individual ones. LHC constraints on simplified models of squarks and sbottoms can be adapted to our case, and monojet searches can be relevant if the spectrum is compressed.

A Couplet from Flavored Dark Matter
A Couplet from Flavored Dark Matter

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Published: 2015

Total Pages: 17

ISBN-13:

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We show that a couplet, a pair of closely spaced photon lines, in the X-ray spectrum is a distinctive feature of lepton flavored dark matter models for which the mass spectrum is dictated by Minimal Flavor Violation. In this scenario, mass splittings between different dark matter flavors are determined by Standard Model Yukawa couplings and can naturally be small, allowing all three flavors to be long-lived and contribute to the observed abundance. Then, in the presence of a tiny source of flavor violation, heavier dark matter flavors can decay via a dipole transition on cosmological timescales, giving rise to three photon lines. Two of these lines are closely spaced, and constitute the couplet. Provided the flavor violation is sufficiently small, the ratios of the line energies are determined in terms of the charged lepton masses, and constitute a prediction of this framework. Furthermore, for dark matter masses of order the weak scale, the couplet lies in the keV-MeV region, with a much weaker line in the eV-keV region. This scenario constitutes a potential explanation for the recent claim of the observation of a 3.5 keV line. As a result, the next generation of X-ray telescopes may have the necessary resolution to resolve the double line structure of such a couplet.

Supersymmetry Beyond Minimality
Supersymmetry Beyond Minimality

Author: Shaaban Khalil

Publisher: CRC Press

Published: 2017-12-06

Total Pages: 394

ISBN-13: 1315350874

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Supersymmetry (SUSY) is one of the most important ideas ever conceived in particle physics. It is a symmetry that relates known elementary particles of a certain spin to as yet undiscovered particles that differ by half a unit of that spin (known as Superparticles). Supersymmetric models now stand as the most promising candidates for a unified theory beyond the Standard Model (SM). SUSY is an elegant and simple theory, but its existence lacks direct proof. Instead of dismissing supersymmetry altogether, Supersymmetry Beyond Minimality: from Theory to Experiment suggests that SUSY may exist in more complex and subtle manifestation than the minimal model. The book explores in detail non-minimal SUSY models, in a bottom-up approach that interconnects experimental phenomena in the fermionic and bosonic sectors. The book considers with equal emphasis the Higgs and Superparticle sectors, and explains both collider and non-collider experiments. Uniquely, the book explores charge/parity and lepton flavour violation. Supersymmetry Beyond Minimality: from Theory to Experiment provides an introduction to well-motivated examples of such non-minimal SUSY models, including the ingredients for generating neutrino masses and/or relaxing the tension with the heavily constraining Large Hadron Collider (LHC) data. Examples of these scenarios are explored in depth, in particular the discussions on Next-to-Minimal Supersymmetric SM (NMSSM) and B-L Supersymmetric SM (BLSSM).

Theory and Design of Charged Particle Beams
Theory and Design of Charged Particle Beams

Author: Martin Reiser

Publisher: John Wiley & Sons

Published: 2008-09-26

Total Pages: 634

ISBN-13: 3527617639

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Although particle accelerators are the book's main thrust, it offers a broad synoptic description of beams which applies to a wide range of other devices such as low-energy focusing and transport systems and high-power microwave sources. Develops material from first principles, basic equations and theorems in a systematic way. Assumptions and approximations are clearly indicated. Discusses underlying physics and validity of theoretical relationships, design formulas and scaling laws. Features a significant amount of recent work including image effects and the Boltzmann line charge density profiles in bunched beams.

Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like?
Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like?

Author: Roman Pasechnik

Publisher: Frontiers Media SA

Published: 2020-09-03

Total Pages: 180

ISBN-13: 2889639908

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This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Massive Neutrinos: Flavor Mixing Of Leptons And Neutrino Oscillations
Massive Neutrinos: Flavor Mixing Of Leptons And Neutrino Oscillations

Author: Harald Fritzsch

Publisher: World Scientific

Published: 2015-08-28

Total Pages: 307

ISBN-13: 9814704784

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Since the discovery of neutrino oscillations neutrino physics has become an interesting field of research in physics. They imply that neutrino must have a small mass and that the neutrinos, coupled to the charged leptons, are mixtures of the mass eigenstates, analogous to the flavor mixing of the quarks. The mixing angles for the quarks are small, but for the leptons two of the mixing angles are large. The masses of the three neutrinos must be very small, less than 1 eV, but from the oscillation experiments we only know the mass differences — the absolute masses are still unknown. Also we do not know, if the masses of the neutrinos are Dirac masses, as the masses of the charged leptons and of the quarks, or whether they are Majorana masses.In this volume, an overview of the present state of research in neutrino physics is given by well-known experimentalists and theorists. The contents — originated from talks and discussions at a recent conference addressing some of the most pressing open questions in neutrino physics — range from the oscillation experiments to CP-violation for leptons, to texture zero mass matrices and to the role of neutrinos in astrophysics and cosmology.

Sterile Neutrino Dark Matter
Sterile Neutrino Dark Matter

Author: Alexander Merle

Publisher: Morgan & Claypool Publishers

Published: 2017-05-10

Total Pages: 125

ISBN-13: 1681744821

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This book is a new look at one of the hottest topics in contemporary science, Dark Matter. It is the pioneering text dedicated to sterile neutrinos as candidate particles for Dark Matter, challenging some of the standard assumptions which may be true for some Dark Matter candidates but not for all. So, this can be seen either as an introduction to a specialized topic or an out-of-the-box introduction to the field of Dark Matter in general. No matter if you are a theoretical particle physicist, an observational astronomer, or a ground based experimentalist, no matter if you are a grad student or an active researcher, you can benefit from this text, for a simple reason: a non-standard candidate for Dark Matter can teach you a lot about what we truly know about our standard picture of how the Universe works.