arXiv subjects

N. Setzer

Publications and source records attributed to N. Setzer.

8 recordsLinked to original sources

arXiv2013

Contamination of Dark Matter Experiments from Atmospheric Magnetic Dipoles

Dark matter collisions with heavy nuclei (Xe, Ge, Si, Na) may produce recoils observable at direct-search experiments. Given that some of these experiments are yielding conflicting information, however, it is worth asking if physics other than dark matter may produce similar nuclear recoils. We examine under what conditions an atmospherically-produced neutral particle with a relatively large magnetic dipole moment could fake a dark matter signal. We argue that a very definite flux could explain the signals seen at DAMA/LIBRA, CDMS/Si and CoGeNT consistently with the bounds from XENON100 and CDMS/Ge. To explore the plausibility of this scenario, we discuss a concrete model with 10-50 MeV sterile neutrinos that was recently proposed to explain the LSND and MiniBooNE anomalies.

hep-ph↗

arXiv2011

When Anomaly Mediation is UV Sensitive

Despite its successes---such as solving the supersymmetric flavor problem---anomaly mediated supersymmetry breaking is untenable because of its prediction of tachyonic sleptons. An appealing solution to this problem was proposed by Pomarol and Rattazzi where a threshold controlled by a light field deflects the anomaly mediated supersymmetry breaking trajectory, thus evading tachyonic sleptons. In this paper we examine an alternate class of deflection models where the non-supersymmetric threshold is accompanied by a heavy, instead of light, singlet. The low energy form of this model is the so-called extended anomaly mediation proposed by Nelson and Weiner, but with potential for a much higher deflection threshold. The existence of this high deflection threshold implies that the space of anomaly mediated supersymmetry breaking deflecting models is larger than previously thought.

hep-th↗

arXiv2010

On the stability of a soft-wall model

We investigate the stability and fluctuations of a soft wall model that has an asymptotically AdS metric and a scalar field that has an asymptotically power-law dependence in the conformal coordinate. By imposing UV boundary conditions, the soft wall mass scale can be fixed to be near the TeV scale and causes the radion to no longer be massless. A hierarchy between the weak scale and the Planck scale can be generated for various particle spectrum behavior, although natural values only occur for a gravitational sector containing scalar fields that act like unparticles. In addition, if bulk Standard Model fields have nonstandard couplings to the gravitational sector, then a discrete particle spectrum can be realized in the nongravitational sector. This allows for the possibility of an unparticle solution to the hierarchy problem.

hep-ph↗

arXiv2008

Seesaw Extended MSSM and Anomaly Mediation without Tachyonic Sleptons

Superconformal anomalies provide an elegant and economical way to understand the soft breaking parameters in SUSY models; however, implementing them leads to the several undesirable features including: tachyonic sleptons and electroweak symmetry breaking problems in both the MSSM and the NMSSM. Since these two theories also have the additonal problem of massless neutrinos, we have reconsidered the AMSB problems in a class of models that extends the NMSSM to explain small neutrino masses via the seesaw mechanism. In a recent paper, we showed that for a class of minimal left-right extensions, a built-in mechanism exists which naturally solves the tachyonic slepton problem and provides new alternatives to the MSSM that also have automatic R-parity conservation. In this paper, we discuss how electroweak symmetry breaking arises in this model through an NMSSM-like low energy theory with a singlet VEV, induced by the structure of the left-right extension and of the right magnitude. We then study the phenomenological issues and find: the LSP is an Higgsino-wino mix, new phenomenology for chargino decays to the LSP, degenerate same generation sleptons and a potential for a mild squark-slepton degeneracy. We also discuss possible collider signatures and the feasibility of dark matter in this model.

hep-ph↗

arXiv2007

Minimal Seesaw as an Ultraviolet Insensitive Cure for the Problems of Anomaly Mediation

We show that an intermediate scale supersymmetric left-right seesaw scenario with automatic R-parity conservation can cure the problem of tachyonic slepton masses that arises when supersymmetry is broken by anomaly mediation, while preserving ultraviolet insensitivity. The reason for this is the existence of light B - L = 2 higgses with yukawa couplings to the charged leptons. We find these theories to have distinct predictions compared to the usual mSUGRA and gauge mediated models as well as the minimal AMSB models. Such predictions include a condensed gaugino mass spectrum and possibly a correspondingly condensed sfermion spectrum.

hep-ph↗

arXiv2006

Running with Triplets: How Slepton Masses Change With Doubly-Charged Higgses

We examine the slepton masses of SUSYLR models and how they change due the presence of light-doubly charged higgs bosons. We discover that the measurement of the slepton masses could bound and even predict the value of the third generation Yukawa coupling of leptons to the SU(2)_R Triplets. We also consider the unification prospects for this model with the addition of left-handed, B - L = 0 triplets--a model we call the Triplet Extended Supersymmetric Standard Model (TESSM). Finally, we discuss the changes in the slepton masses due to the presence of the SU(2)_L triplets.

hep-ph↗

arXiv2005

Predicting the Seesaw Scale in a Minimal Bottom-Up Extension of MSSM

We analyze a minimal bottom-up seesaw scenario where we require the theory to satisfy three phenomenological conditions: (i)it is supersymmetric; (ii) it has a local B-L symmetry as part of the SU(2)_L x SU(2)_R x U(1)_{B-L} gauge theory to implement the seesaw mechanism and (iii) B-L symmetry breaking is such that it leaves R-parity unbroken giving a naturally stable dark matter. We show that in such a theory, one can predict the seesaw scale for neutrino masses to be M_R ~ \sqrt{M_{SUSY} M_{Pl}} ~ 10^{11} GeV. We show that the ground state with this property is a stable minimum and is lower than possible electric charge violating minimum in this theory. Such models in their generic version are known to predict the existence of a light doubly charged Higgs boson and Higgsino which can be searched for in collider experiments. We give expressions for their masses in this minimal version. We then indicate how one can get different expectation values for the MSSM Higgs doublets in the theory required to have realistic quark masses.

hep-ph↗

arXiv2005

One-loop RGEs for two left-right SUSY models

In this paper we present the renormalization group equations to one-loop order for all the parameters of two supersymmetric left-right theories that are softly broken. Both models are based upon the gauge group SU(3)^c x SU(2)_L x SU(2)_R x U(1)_{B - L} and both contain an arbitrary number of bidoublets as well as singlets; however, one model uses doublets to break SU(2)_R and the other uses triplets.

hep-ph↗