1,930 research outputs found
On the Correlation Between the Spin-Independent and Spin-Dependent Direct Detection of Dark Matter
We study the correlation between spin-independent and spin-dependent
scattering in the context of MSSM neutralino dark matter for both thermal and
non-thermal histories. We explore the generality of this relationship with
reference to other models. We discuss why either fine-tuning or numerical
coincidences are necessary for the correlation to break down. We derive upper
bounds on spin-dependent scattering mediated by a Z boson.Comment: 31 pages, 6 figures, 3 appendices; v2: refs added, minor typos
corrected, journal versio
Asymmetric Dark Matter from a GeV Hidden Sector
Asymmetric Dark Matter (ADM) models relate the dark matter density to the
baryon asymmetry, so that a natural mass scale for ADM is around a few GeV. In
existing models of ADM, this mass scale is unexplained; here we generate this
GeV scale for dark matter (DM) from the weak scale via gauge kinetic mixing
with a new Abelian dark force. In addition, this dark sector provides an
efficient mechanism for suppressing the symmetric abundance of DM through
annihilations to the dark photon. We augment this sector with a higher
dimensional operator responsible for communicating the baryon asymmetry to the
dark sector. Our framework also provides DM candidate for gauge mediation
models. It results in a direct detection cross section of interest for current
experiments: sigma less than or similar to 10^{-42} cm^2 for DM masses in the
range 1 - 15 GeV.Comment: 21 pages, 4 figure
Collinear superspace
This paper provides a superfield based approach to constructing a collinear slice of N=1 superspace. The strategy is analogous to integrating out anticollinear fermionic degrees-of-freedom as was developed in the context of soft-collinear effective theory. The resulting Lagrangian can be understood as an integral over collinear superspace, where half the supercoordinates have been integrated out. The application to N=1 super Yang-Mills is presented. Collinear superspace provides the foundation for future explorations of supersymmetric soft-collinear effective theory.National Science Foundation (U.S.) (PHY–0969510)National Science Foundation (U.S.) (PHY–1419008)National Science Foundation (U.S.) (PHY–1066293
Supersymmetric Baryogenesis from Exotic Quark Decays
In a simple extension of the minimal supersymmetric standard model,
out-of-equilibrium decays of TeV scale exotic vector-like squarks may generate
the baryon asymmetry of the universe. Baryon number and CP violation are
present in the superpotential, so this mechanism does not rely on CP violation
in supersymmetry breaking parameters. We discuss phenomenological constraints
on the model as well as potential signals for the Large Hadron Collider and
electronic dipole moment experiments. A variation on the TeV scale model allows
the exotic squarks to be the messengers of gauge mediated supersymmetry
breaking.Comment: 28 pages, 7 figures, 2 appendices, v2: typos corrected, results
unchange
Circumnavigating Collinear Superspace
In this paper, we extend the collinear superspace formalism to include the
full range of supersymmetric interactions. Building on the
effective field theory rules developed in a companion paper - "Navigating
Collinear Superspace" - we construct collinear superspace Lagrangians for
theories with non-trivial - and -term auxiliary fields. For (massless)
Wess-Zumino models, the key ingredient is a novel type of Grassmann-valued
supermultiplet whose lowest component is a (non-propagating) fermionic degree
of freedom. For gauge theories coupled to charged chiral matter, the key
ingredient is a novel type of vector superfield whose lowest component is a
non-propagating gauge potential. This unique vector superfield is used to
construct a gauge-covariant derivative; while such an object does not appear in
the standard full superspace formalism, it is crucial for modeling gauge
interactions when the theory is expressed on a collinear slice. This brings us
full circle, by showing that all types of theories in four
dimensions can be constructed in collinear superspace from purely infrared
considerations. We speculate that supersymmetric theories with could also be implemented using similar collinear superspace constructions.Comment: 51 pages plus appendix, 7 tables. v3 Published versio
Transsylvian selective amygdalohippocampectomy for treatment of medial temporal lobe epilepsy: Surgical technique and operative nuances to avoid complications
Background:
A number of different surgical techniques are effective for treatment of drug-resistant medial temporal lobe epilepsy. Of these, transsylvian selective amygdalohippocampectomy (SA), which was originally developed to maximize temporal lobe preservation, is arguably the most technically demanding to perform. Recent studies have suggested that SA may result in better neuropsychological outcomes with similar postoperative seizure control as standard anterior temporal lobectomy, which involves removal of the lateral temporal neocortex.
Methods:
In this article, the authors describe technical nuances to improve the safety of SA.
Results:
Wide sylvian fissure opening and use of neuronavigation allows an adequate exposure of the amygdala and hippocampus through a corticotomy within the inferior insular sulcus. Avoidance of rigid retractors and careful manipulation and mobilization of middle cerebral vessels will minimize ischemic complications. Identification of important landmarks during amygdalohippocampectomy, such as the medial edge of the tentorium and the third nerve within the intact arachnoid membranes covering the brainstem, further avoids operator disorientation.
Conclusion:
SA is a safe technique for resection of medial temporal lobe epileptogenic foci leading to drug-resistant medial temporal lobe epilepsy
Elliptic curves, modular forms, and sums of Hurwitz class numbers
Let H(N) denote the Hurwitz class number. It is known that if is a prime,
then {equation*} \sum_{|r|<2\sqrt p}H(4p-r^2) = 2p. {equation*} In this paper,
we investigate the behavior of this sum with the additional condition . Three different methods will be explored for determining the values
of such sums. First, we will count isomorphism classes of elliptic curves over
finite fields. Second, we will express the sums as coefficients of modular
forms. Third, we will manipulate the Eichler-Selberg trace for ula for Hecke
operators to obtain Hurwitz class number relations. The cases and 4 are
treated in full. Partial results, as well as several conjectures, are given for
and 7.Comment: Preprint of an old pape
Allogeneic hematopoietic cell transplantation as curative therapy for patients with non-Hodgkin lymphoma: Increasingly successful application to older patients
AbstractNon-Hodgkin lymphoma (NHL) constitutes a collection of lymphoproliferative disorders with widely varying biological, histological, and clinical features. For the BÂ cell NHLs, great progress has been made due to the addition of monoclonal antibodies and, more recently, other novel agents including BÂ cell receptor signaling inhibitors, immunomodulatory agents, and proteasome inhibitors. Autologous hematopoietic cell transplantation (auto-HCT) offers the promise of cure or prolonged remission in some NHL patients. For some patients, however, auto-HCT may never be a viable option, whereas in others, the disease may progress despite auto-HCT. In those settings, allogeneic HCT (allo-HCT) offers the potential for cure. Over the past 10 to 15Â years, considerable progress has been made in the implementation of allo-HCT, such that this approach now is a highly effective therapy for patients up to (and even beyond) age 75Â years. Recent advances in conventional lymphoma therapy, peritransplantation supportive care, patient selection, and donor selection (including the use of alternative hematopoietic cell donors), has allowed broader application of allo-HCT to patients with NHL. As a result, an ever-increasing number of NHL patients over age 60 to 65Â years stand to benefit from allo-HCT. In this review, we present data in support of the use of allo-HCT for patients with diffuse large BÂ cell lymphoma, follicular lymphoma, and mantle cell lymphoma. These histologies account for a large majority of allo-HCTs performed for patients over age 60 in the United States. Where possible, we highlight available data in older patients. This body of literature strongly supports the concept that allo-HCT should be offered to fit patients well beyond age 65 and, accordingly, that this treatment should be covered by their insurance carriers
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