- Isospin-Violating Dark Matter Benchmarks for Snowmass 2013

- Abstract: Isospin-violating dark matter (IVDM) generalizes the standard spin-independent scattering parameter space by introducing one additional parameter, the neutron-to-proton coupling ratio f_n/f_p. In IVDM the implications of direct detection experiments can be altered significantly. We review the motivations for considering IVDM and present benchmark models that illustrate some of the qualitatively different possibilities. IVDM strongly motivates the use of a variety of target nuclei in direct detection experiments.
- Contributors: Jason Kumar, Jonathan L. Feng, Danny Marfatia and David Sanford
- Preprint Number: CETUP2013-001

- Phenomenology of Dirac Neutralino Dark Matter

- Contributors: Matthew R. Buckley, Dan Hooper and Jason Kumar
- Preprint Number: CETUP2013-002

- Non-thermal Dark Matter in String Compactifications

- Contributors: Rouzbeh Allahverdi, Michele Cicoli, Bhaskar Dutta, Kuver Sinha
- Preprint Number: CETUP2013-003

- Lowering the Threshold in the DAMA Dark Matter Search

- Abstract: The DAMA experiment searches for Weakly Interacting Massive Particle (WIMP) dark matter via its expected but rare interactions within the detector, where the interaction rates will modulate throughout the year due to the orbital motion of the Earth. Over the course of more than 10 years of operation, DAMA has indeed detected a strong modulation in the event rate above the detector threshold of 2 keVee. Under standard assumptions regarding the dark matter halo and WIMP interactions, this signal is consistent with that expected of WIMPs of two different approximate masses: ~10 GeV and ~70 GeV. We examine how a lower threshold, allowed by recent upgrades to the DAMA detector, may shed light on this situation. We find that the lower threshold data should rule out one of the two mass ranges in the spin-independent case at a minimum of the 2.6-sigma level in the worst case scenario. It is unlikely, however, that the data will discriminate between spin-independent and spin-dependent interactions, although for some particular measurements of the modulation in the lowest energy bins this could be achieved. Our findings illustrate the importance of a low threshold in modulation searches.
- Contributors: Chris Kelso, Pearl Sandick and Christopher Savage
- Preprint Number: CETUP2013-004

- Cosmic Variance of the Spectral Index from Mode Coupling

- Abstract: We demonstrate that local, scale-dependent non-Gaussianity can generate cosmic variance uncertainty in the observed spectral index of primordial curvature perturbations. In a universe much larger than our current Hubble volume, locally unobservable long wavelength modes can induce a scale-dependence in the power spectrum of typical subvolumes, so that the observed spectral index varies at a cosmologically significant level (|Delta n_s| ~ O(0.04)). Similarly, we show that the observed bispectrum can have an induced scale dependence that varies about the global shape. If tensor modes are coupled to long wavelength modes of a second field, the locally observed tensor power and spectral index can also vary. All of these effects, which can be introduced in models where the observed non-Gaussianity is consistent with bounds from the {\it Planck} satellite, loosen the constraints that observations place on the parameters of theories of inflation with mode coupling. We suggest observational constraints that future measurements could aim for to close this window of cosmic variance uncertainty.
- Contributors: Joseph Bramante, Jason Kumar, Elliot Nelson and Sarah Shandera
- Preprint Number: CETUP2013-005

- LHC Phenomenology of SO(10) models with Yukawa Unification

- Contributors: A. Anandakrishnan, B. Bryant, S. Raby and A. Wingerter
- Preprint Number: CETUP2013-006

- Unified framework for matter and dark matter

- Abstract: Dark matter may be stable in the same way that the proton is stable. This hints at the possibility of a grand unified theory incorporating both matter and dark matter. A simplest example is discussed with a natural application to the radiative (scotogenic) generation of neutrino mass.
- Contributors: Ernest Ma
- Preprint Number: CETUP2013-007

- On sbottom resonances in Dark Matter scattering

- Abstract: A resonance in the neutralino-nucleus elastic scattering cross section is usually purported when the neutralino-sbottom mass difference ms-mx is equal to the bottom quark mass mb~4 GeV. Such a scenario has been discussed as a viable model for light (~10 GeV) neutralino dark matter as explanation of possible DAMA and CoGeNT direct detection signals. Here we give physical and analytical arguments showing that the sbottom resonance may actually not be there. In particular, we show analytically that the one-loop gluon-neutralino scattering amplitude has no pole at ms=mx+mb, while by analytic continuation to the regime ms less than mx, it develops a pole at ms=mx-mb. In the limit of vanishing gluon momenta, this pole corresponds to the only cut of the neutralino self-energy diagram with a quark and a squark running in the loop, when the decay process x to s+b becomes kinematically allowed. The pole can be interpreted as the formation of a sbqqq resonant state (where qqq are the nucleon valence quarks), which is however kinematically not accessible if the neutralino is the LSP. Our analysis shows that the common practice of estimating the neutralino-nucleon cross section by introducing an ad-hoc pole at ms=mx+mb into the effective four-fermion interaction (also including higher-twist effects) should be discouraged, since it corresponds to adding a spurious pole to the scattering process at the center-of-mass energy ms=mb. Our considerations can be extended from the specific case of supersymmetry to other similar cases in which the dark matter particle scatters off nucleons through the exchange of a b-flavored state almost degenerate in mass with the dark matter particle, such as for instance in theories with extra dimensions and in other mass-degenerate dark matter scenarios recently discussed in the literature.
- Contributors: Paolo Gondolo, Stefano Scopel
- Preprint Number: CETUP2013-008

- Sparticle Spectroscopy from SO(10) GUT with a Unified Higgs Sector

- Abstract: We study the low energy implications, especially the particle spectroscopy, of SO(10) grand unification in which the SO(10) symmetry is broken to the Standard Model gauge group with a single pair of $(144+\overline{144})$ dimensional Higgs multiplet (unified Higgs sector). In this class of models, the asymptotic relation $Y_b\approx Y_{\tau}\approx Y_t/6$ among the third generation quark and lepton Yukawa couplings can be derived. This relation leads to the prediction $\tan\beta \approx 14$, where $\tan\beta$ is the well known MSSM parameter. We find that this type of Yukawa coupling unification {(YU) is realized only by employing non-universal soft supersymmety breaking terms, dictated by SO(10) symmetry, for the gauginos. A 125 GeV Higgs boson mass is also found to be consistent with YU at the $\sim 5\%$ level. Without imposing a constraint on the relic abundance of dark matter in these models, the squark and slepton masses, with the exception of the stop, exceed 2 TeV and the gluino is heavier than 1 TeV. We show that the neutralino in this model is an acceptable dark mater candidate through the neutralino-stop coannihilation scenario, with the stop quark being relatively light ($\gtrsim 500$ GeV)}.
- Contributors: M. Adeel Ajaib, Ilia Gogoladze and Qaisar Shafi
- Preprint Number: CETUP2013-009

- On baryogenesis from dark matter annihilation

- Abstract: We study in detail the conditions to generate the baryon asymmetry of the Universe from the annihilation of dark matter. This scenario requires a low energy mechanism for thermal baryogenesis, hence we first discuss some of these mechanisms together with the specific constraints due to the connection with the dark matter sector. Then we show that, contrary to what stated in previous studies, it is possible to generate the cosmological asymmetry without adding a light sterile dark sector, both in models with violation and with conservation of $B-L$. In addition, one of the models we propose yields some connection to neutrino masses.
- Contributors: Nicolas Bernal, Stefano Colucci, Francois-Xavier Josse-Michaux, J. Racker, Lorenzo Ubaldi
- Preprint Number: CETUP2013-010

- Dipole Moment Bounds on Dark Matter Annihilation

- Abstract: We consider constraints on simplified models in which scalar dark matter annihilates to light charged leptons through the exchange of charged mediators. We find that loop diagrams will contribute corrections to the magnetic and electric dipole moments of the light charged leptons, and experimental constraints on these corrections place significant bounds on the dark matter annihilation cross section. In particular, annihilation to electrons with an observable cross section would be ruled out, while annihilation to muons is only permitted if the dominant contributions arise from CP-violating interactions.
- Contributors: Keita Fukushima and Jason Kumar
- Preprint Number: CETUP2013-011

- Constraining the $Z^{\prime}$ Mass in 331 Models using Direct Dark Matter Detection

- Abstract: We investigate a 331 extension of the Standard Model gauge sector which accommodates neutrino masses and where the lightest of the heavy neutrinos is a viable WIMP dark matter candidate. In this model, processes mediated by the additional $Z^{\prime}$ gauge boson set both the WIMP relic abundance and the scattering cross section of WIMPs off of nuclei. We calculate the WIMP relic abundance including the important effect of coannihilation across the heavy neutrino sector. We find that the recent XENON results put very stringent bounds on the mass of the extra gauge boson, $M_{Z^{\prime}} > 1.6$~TeV, for WIMPs lighter than 1~TeV. Finally, we comment on how our bounds on the $Z^{\prime}$ mass impact generic 331-like models and on implications for LHC phenomenology.
- Contributors: Stefano Profumo and Farinaldo S. Queiroz
- Preprint Number: CETUP2013-012

- SU(5) x SU(5) Twinification And D2 Parity

- Contributors: Zurab Tavartkiladze
- Preprint Number: CETUP2013-013

- A 331 WIMPy Dark Radiation Model

- Abstract: Recent observations suggest that the number of relativistic degrees of freedom in the early universe might exceed what predicted in the standard cosmological model. If even a small, percent-level fraction of dark matter particles are produced relativistically, they could mimic the effect of an extra realistic species at matter-radiation equality while obeying BBN, CMB and Structure Formation bounds. We show that this scenario is quite naturally realized with a weak-scale dark matter particle and a high-scale ``mother' particle within a well motivated 3-3-1 gauge model, which is particularly interesting for being consistent with electroweak precision measurements, with recent LHC results, and for offering a convincing explanation for the number of generations in the Standard Model.
- Contributors: Chris Kelso,C. A. de S. Pires,Stefano Profumo,Farinaldo S. Queiroz and P. S. Rodrigues da Silva
- Preprint Number: CETUP2013-014

- WIMPy Leptogenesis With Absorptive Final State Interactions

- Contributors: Jason Kumar and Patrick Stengel
- Preprint Number: CETUP2013-015

- Higgs phenomenology in Type-I 2HDM with $\bm{U(1)_H}$ Higgs gauge symmetry

- Contributors: P. Ko, Yuji Omura and Chaehyun Yu
- Preprint Number: CETUP2013-016

- Supernova Constraints on MeV Dark Sectors from e+e− Annihilations

- Abstract: Theories with dark forces and dark sectors are of interest for dark matter models. In this paper we find the region in parameter space that is constrained by supernova cooling constraints when the models include dark sector particles with masses around 100 MeV or less. We include only interactions with electrons and positrons. The constraint is important for small mixing parameters.
- Contributors: Herbert Dreiner, Jean-Francois Fortin, Christoph Hanhart, and Lorenzo Ubaldi
- Preprint Number: CETUP2013-017

- Direct Detection Portals for Self-interacting Dark Matter

- Abstract: Dark matter self-interactions can affect the small scale structure of the Universe, reducing the central densities of dwarfs and low surface brightness galaxies in accord with observations. From a particle physics point of view, this points toward the existence of a 1 - 100 MeV particle in the dark sector that mediates self-interactions. Since mediator particles will generically couple to the Standard Model, direct detection experiments provide sensitive probes of self-interacting dark matter. We consider three minimal mechanisms for coupling the dark and visible sectors: photon kinetic mixing, Z boson mass mixing, and the Higgs portal. Self-interacting dark matter motivates a new benchmark paradigm for direct detection via momentum-dependent interactions, and ton-scale experiments will cover astrophysically motivated parameter regimes that are unconstrained by current limits. Direct detection is a complementary avenue to constrain velocity-dependent self-interactions that evade astrophysical bounds from large scales, such as the Bullet cluster.
- Contributors: Manoj Kaplinghat, Sean Tulin, and Hai-Bo Yu
- Preprint Number: CETUP2013-018

- Towards the minimal renormalizable supersymmetric $E_6$ model

- Abstract: We find an explicit renormalizable supersymmetric E6 model with all the ingredients for being realistic. It consists of the Higgs sector 351prime+ 351primebar+27+ 27bar, which breaks E6 directly to the Standard Model gauge group. Three copies of 27 dimensional representations then describe the matter sector, while an extra 27+27bar pair is needed to successfully split the Standard Model Higgs doublet from the heavy Higgs triplet. Also, we show why some other simpler E6 models fail to be realistic at the renormalizable level.
- Contributors: Borut Bajc and Vasja Susic
- Preprint Number: CETUP2013-019

- Matter-Neutrino Resonance Above Merging Compact Objects

- Abstract: Accretion disks arising from neutron star- neutron star mergers or black hole- neutron star merg- ers, produce large numbers of neutrinos and antineutrinos. In contrast to other astrophysical sce- narios, like supernovae, in mergers the antineutrinos outnumber the neutrinos. This antineutrino dominance gives neutrinos from merger disks the opportunity to exhibit new oscillation physics, ie, a matter-neutrino resonance. We explore this resonance, finding that consequences can be a large transition of νe to other flavors. We present numerical calculations of neutrinos from merger disks and compare with a single energy model. We explain both the basic features and the conditions for a transition.
- Contributors: A. Malkus , A. Friedland, and G. C. McLaughlin
- Preprint Number: CETUP2013-020

- The Incredible Bulk

- Abstract: Recent experimental results from the LHC have placed strong constraints on the masses of colored superpartners. The MSSM parameter space is also constrained by the measurement of the Higgs boson mass, and the requirement that the relic density of lightest neutralino be consistent with observation. Although large regions of the MSSM parameter space can be excluded by these combined bounds, leptophilic versions of the MSSM can survive these constraints. In this paper we consider a scenario in which the requirements of minimal flavor violation, vanishing $CP$-violation, and mass universality are relaxed, specifically focusing on scenarios with light sleptons. We find a large region of parameter space, analogous to the original bulk region, for which the lightest neutralino is a thermal relic with an abundance consistent with that of dark matter. We find that these leptophilic models are constrained by measurements of the magnetic and electric dipole moments of the electron and muon, and that these models have interesting signatures at a variety of indirect detection experiments.
- Contributors: Keita Fukushima, Chris Kelso, Jason Kumar, Pearl Sandick and Takahiro Yamamoto
- Preprint Number: CETUP2013-021

- The Dark $Z^{\prime}$ Portal: Direct, Indirect and Collider Searches

- Abstract: We perform a detailed study of the dark $\zp$ portal using a generic parametrization of the $\zp$-quarks couplings, both for light ($8-15$)~GeV and heavy ($100-1000$)~GeV dark matter scenarios. We present a comprehensive study of the collider phenomenology including jet clustering, hadronization, and detector artifacts, which allows us to derive accurate bounds from the search for new resonances in dijet events and from mono-jet events in the LHC $7$~TeV, LHC $8$~TeV, and Tevatron $1.96$~TeV data. We also compute the dark matter relic abundance, the relevant scattering cross sections and pair-annihilation spectrum, and compare our results with the current PLANCK, Fermi-LAT and XENON100/LUX bounds. Lastly, we highlight the importance of complementary searches for dark matter, and outline the excluded versus still viable parameter space regions of the dark $\zp$ portal.
- Contributors: Alexandre Alves,Stefano Profumo, Farinaldo S. Queiroz
- Preprint Number: CETUP2013-022

- The Muon Anomalous Magnetic Moment in the Reduced Minimal 3-3-1 Model

- Abstract: We study the muon anomalous magnetic moment $(g-2)_{\mu}$ in the context of the reduced minimal 3-3-1 model recently proposed in the literature. In particular, its spectrum contains a doubly charged scalar ($H^{\pm \pm}$) and gauge boson ($U^{\pm \pm}$), new singly charged vectors ($V^{\pm}$) and a $Z^{\prime}$ boson, each of which might give a sizeable contribution to the $(g-2)_{\mu}$. We compute the 1-loop contributions from all these new particles to the $(g-2)_{\mu}$. We conclude that the doubly charged vector boson provides the dominant contribution, and by comparing our results with the experimental constraints we derive an expected value for the scale of $SU(3)_L\otimes U(1)_N$ symmetry breaking $v_{\chi} \sim 2$ TeV. We also note that, if the discrepancy in the anomalous moment is resolved in the future without this model then the constraints will tighten to requiring $v_\chi > 2.7$ TeV with current precision, and will entirely rule out the model if the expected precision is achieved by the future experiment at Fermilab.
- Contributors: Chris Kelso, P.R.D. Pinheiro, Farinaldo S. Queiroz, William Shepherd
- Preprint Number: CETUP2013-023

- New Physics Contributions to the Muon Anomalous Magnetic Moment: A Numerical Code

- Abstract: We consider the contributions of individual new particles to the anomalous magnetic moment of the muon, utilizing the generic framework of simplified models. We also present analytic results for all possible one-loop contributions, allowing easy application of these results for more complete models which predict more than one particle capable of correcting the muon magnetic moment. Additionally, we provide a Mathematica code to allow the reader straightforwardly compute any 1-loop contribution. Furthermore, we derive bounds on each new particle considered, assuming either the absence of other significant contributions to $a_\mu$ or that the anomaly has been resolved by some other mechanism. The simplified models we consider are constructed without the requirement of $SU(2)_L$ invariance, but appropriate chiral coupling choices are also considered. In summary, we found the following particles capable of explaining the current discrepancy, assuming unit couplings: $2$~TeV ($0.3$~TeV) neutral scalar with pure scalar (chiral) couplings, $4$~TeV doubly charged scalar with pure pseudoscalar coupling, $0.3-1$~TeV neutral vector boson depending on what couplings are used (vector, axial, or mixed), $0.5-1$~TeV singly-charged vector boson depending on which couplings are chosen, and $3$~TeV doubly-charged vector-coupled bosons. We also derive the following $1\sigma$ lower bounds on new particle masses assuming unit couplings and that the experimental anomaly has been otherwise resolved: a doubly charged pseudo-scalar must be heavier than $7$~TeV, a neutral scalar than $3$~TeV, a vector-coupled new neutral boson $600$~GeV, an axial-coupled neutral boson $1.5$~TeV, a singly-charged vector-coupled $W^\prime$ $1$~TeV, a doubly-charged vector-coupled boson $5$~TeV, scalar leptoquarks $10$~TeV, and vector leptoquarks $10$~TeV.
- Contributors: Farinaldo S. Queiroz and William Shepherd
- Preprint Number: CETUP2013-024

- The Poker Face of the Majoron Dark Matter Model: LUX to keV Line

- Abstract: We study the viability of pseudo Nambu-Goldstone bosons (Majorons) arising in see-saw models as dark matter candidates. Interestingly the stability of the Majoron as dark matter is related to the scale that sets the see-saw and leptogenesis mechanisms, while its annihilation and scattering cross section off nuclei can be set through the Higgs portal. For $\mathcal{O}(GeV) - \mathcal{O}(TeV)$ Majorons, we compute observables such as the abundance, scattering cross section, Higgs invisible decay width, and emission lines and compare with current data in order to outline the excluded versus still viable parameter space regions. We conclude that the simplest Majoron dark matter models coupling through the Higgs portal, except at the Higgs resonance, are excluded by current direct detection data for Majorons lighter than $225$~GeV and future runnings are expected to rule out decisively the 1GeV-1TeV window. Lastly, we point out that light keV-scale Majorons whose relic density is set by thermal freeze-in from sterile neutrinos can account for the keV line observed by XMM-Newton observatory in the spectrum of 73 galaxy clusters, within a see-saw model with a triplet Higgs.
- Contributors: Farinaldo S. Queiroz and Kuver Sinha
- Preprint Number: CETUP2013-025

- A Rich Tapestry: Supersymmetric Axions, Dark Radiation, and Inflationary Reheating

- Abstract: We exploit the complementarity among supersymmetry, inflation, axions, Big Bang Nucleosynthesis (BBN) and Cosmic Microwave Background Radiation (CMB) to constrain supersymmetric axion models in the light of the recent Planck and BICEP results. In particular, we derive BBN bounds coming from altering the light element abundances by taking into account hadronic and electromagnetic energy injection, and CMB constraints from black-body spectrum distortion. Lastly, we outline the viable versus excluded region of these supersymetric models that might account for the mild dark radiation observed.
- Contributors: Farinaldo S. Queiroz, Kuver Sinha, William Wester
- Preprint Number: CETUP2013-026

- Flavor Symmetry Based MSSM (sMSSM): Theoretical Models and Phenomenological Analysis

- Abstract: We present a class of supersymmetric models in which symmetry considerations alone dictate the form of the soft SUSY breaking Lagrangian. We develop a class of minimal models, denoted as sMSSM -- for flavor symmetry-based minimal supersymmetric standard model, which respect a grand unified symmetry such as SO(10) and a non-Abelian flavor symmetry H which suppresses SUSY-induced flavor violation. Explicit examples are constructed with the flavor symmetry being gauged SU(2)_H and SO(3)_H with the three families transforming as 2 + 1 and 3 representations respectively. A simple solution is found in the case of SU(2)_H for suppressing the flavor violating D--terms based on an exchange symmetry. Explicit models based on SO(3)_H without the D--term problem are developed. In addition, models based on discrete non-Abelian flavor groups are presented which are automatically free from D--term issues. The permutation group S_3 with a 2 + 1 family assignment, as well as the tetrahedral group A_4 with a 3 assignment are studied. In all cases, a simple solution to the SUSY CP problem is found, based on spontaneous CP violation leading to a complex quark mixing matrix. We develop the phenomenology of the resulting sMSSM, which is controlled by seven soft SUSY breaking parameters for both the 2 + 1 assignment and the 3 assignment of fermion families. These models are special cases of the phenomenological MSSM (pMSSM), but with symmetry restrictions. We discuss the parameter space of sMSSM compatible with LHC searches, B physics constraints and dark matter relic abundance. Fine-tuning in these models is relatively mild, since all SUSY particles can have masses below about 3 TeV.
- Contributors: K.S. Babu, Ilia Gogoladze, Shabbar Raza, Qaisar Shafi
- Preprint Number: CETUP2013-027

- Muon g-2, 125 GeV Higgs and Neutralino Dark Matter in sMSSM

- Abstract: We discuss the sparticle (and Higgs) spectrum in a class of flavor symmetry-based minimal supersymmetric standard models, referred to here as sMSSM. In this framework the SUSY breaking Lagrangian takes the most general form consistent with a grand unified symmetry such as SO(10) and a non-Abelian flavor symmetry acting on the three families with either a 2+1 or a 3 family assignment. Models based on gauged SU(2) and SO(3) flavor symmetry, as well as non-Abelian discrete symmetries such as S_3 and A_4, have been suggested which fall into this category. These models describe supersymmetry breaking in terms of seven phenomenological parameters. The soft supersymmetry breaking masses at M_GUT of all sfermions of the first two families are equal in sMSSM, which differ in general from the corresponding third family mass. In such a framework we show that the muon g-2 anomaly, the observed Higgs boson mass of ~ 125 GeV, and the observed relic neutralino dark matter abundance can be simultaneously accommodated. The resolution of the muon g-2 anomaly in particular yields the result that the first two generation squark masses, as well the gluino mass, should be <~ 2 TeV, which will be tested at LHC14.
- Contributors: K. S. Babu, Ilia Gogoladze, Qaisar Shafi, Cem Salih Un
- Preprint Number: CETUP2013-028

- Neutrino Magnetic Moment, CP Violation and Flavor Oscillations in Matter

- Abstract: We consider collective oscillations of neutrinos, which are emergent nonlinear flavor evolution phenomena instigated by neutrino-neutrino interactions in astrophysical environments with sufficiently high neutrino densities. We investigate the symmetries of the problem in the full three flavor mixing scheme and in the exact many-body formulation by including the effects of CP violation and neutrino magnetic moment. We show that, similar to the two flavor scheme, several dynamical symmetries exist for three flavors in the single-angle approximation if the net electron background in the environment and the effects of the neutrino magnetic moment are negligible. Moreover, we show that these dynamical symmetries are present even when the CP symmetry is violated in neutrino oscillations. We explicitly write down the constants of motion through which these dynamical symmetries manifest themselves in terms of the generators of the SU(3) flavor transformations. We also show that the effects due to the CP-violating Dirac phase factor out of the many-body evolution operator and evolve independently of nonlinear flavor transformations if neutrino electromagnetic interactions are ignored. In the presence of a strong magnetic field, CP-violating effects can still be considered independently provided that an effective definition for neutrino magnetic moment is used.
- Contributors: Y. Pehlivan, A. B. Balantekin, Toshitaka Kajino
- Preprint Number: CETUP2013-030