224 research outputs found
Experimental signatures of low energy gauge mediated supersymmetry breaking
The experimental signatures for gauge mediated supersymmetry breaking are presented. The phenomenology associated with this class of models is distinctive since the gravitino is naturally the LSP. The next lightest supersymmetric particle (NLSP) can be a gaugino, Higgsino, or right handed slepton. Decay of the NLSP to its partner plus the LSP proceeds through the Goldstino component of the gravitino. For a significant range of parameters this decay can take place within the detector, and can be measured as a displaced vertex or kink in a charged particle track. In the case that the NLSP is mostly gaugino, we identify the discovery modes as e^+e^- \rightarrow \gamma \gamma + \Emiss, and p \bar{p} \rightarrow l^+ l^- \gamma \gamma + \EmissT. If the NLSP is a right handed slepton the discovery modes are e^+ e^- \rightarrow l^+ l^- + \Emiss and p \bar{p} \rightarrow l^+ l^- + \EmissT. An NLSP which is mostly Higgsino is also considered. Finally, these theories can contain scalar particles which mediate sub-millimeter range coherent forces of gravitational strength
Low Energy Supersymmetry from the Heterotic Landscape
We study possible correlations between properties of the observable and
hidden sectors in heterotic string theory. Specifically, we analyze the case of
the Z6-II orbifold compactification which produces a significant number of
models with the spectrum of the supersymmetric standard model. We find that
requiring realistic features does affect the hidden sector such that hidden
sector gauge group factors SU(4) and SO(8) are favoured. In the context of
gaugino condensation, this implies low energy supersymmetry breaking.Comment: 4 pages, 3 figures; to appear in Phys. Rev. Let
S22RS SGR No. 24 (Carceral Labor)
A Resolution
To urge and request Louisiana State University to issue an official public statement regarding their plans for carceral labor to not return to the A&M Campu
Diagnosing Spin at the LHC via Vector Boson Fusion
We propose a new technique for determining the spin of new massive particles
that might be discovered at the Large Hadron Collider. The method relies on
pair-production of the new particles in a kinematic regime where the vector
boson fusion production mechanism is enhanced. For this regime, we show that
the distribution of the leading jets as a function of their relative azimuthal
angle can be used to distinguish spin-0 from spin-1/2 particles. We illustrate
this effect by considering the particular cases of (i) strongly-interacting,
stable particles and (ii) supersymmetric particles carrying color charge. We
argue that this method should be applicable in a wide range of new physics
scenarios.Comment: 5 pages, 4 figure
A unique Z_4^R symmetry for the MSSM
We consider the possible anomaly free Abelian discrete symmetries of the MSSM
that forbid the mu-term at perturbative order. Allowing for anomaly
cancellation via the Green-Schwarz mechanism we identify discrete R-symmetries
as the only possibility and prove that there is a unique Z_4^R symmetry that
commutes with SO(10). We argue that non-perturbative effects will generate a
mu-term of electroweak order thus solving the mu-problem. The non-perturbative
effects break the Z_4^R symmetry leaving an exact Z_2 matter parity. As a
result dimension four baryon- and lepton-number violating operators are absent
while, at the non-perturbative level, dimension five baryon- and lepton-number
violating operators get induced but are highly suppressed so that the nucleon
decay rate is well within present bounds.Comment: 6 page
parity violation from discrete symmetries
We consider supersymmetric extensions of the standard model in which the
usual or matter parity gets replaced by another or non- discrete
symmetry that explains the observed longevity of the nucleon and solves the
problem of MSSM. In order to identify suitable symmetries, we develop a
novel method of deriving the maximal symmetry that
satisfies a given set of constraints. We identify parity violating (RPV)
and conserving models that are consistent with precision gauge unification and
also comment on their compatibility with a unified gauge symmetry such as the
Pati-Salam group. Finally, we provide a counter-example to the statement found
in the recent literature that the lepton number violating RPV scenarios must
have term and the bilinear operator of comparable
magnitude.Comment: v2: references added, minor corrections; matches published version in
Nucl. Phys.
A Mini-Landscape of Exact MSSM Spectra in Heterotic Orbifolds
We explore a ``fertile patch'' of the heterotic landscape based on a Z_6-II
orbifold with SO(10) and E_6 local GUT structures. We search for models
allowing for the exact MSSM spectrum. Our result is that of order 100 out of a
total 3\times 10^4 inequivalent models satisfy this requirement.Comment: 13 pages, for associated information see
http://www.th.physik.uni-bonn.de/nilles/Z6IIorbifold/, v2: matches version
published in PL
Polymorphisms in IL12A and cockroach allergy in children with asthma
<p>Abstract</p> <p>Background</p> <p>IL12A has been implicated in T-cell development and may thus influence the development of atopy and allergic diseases.</p> <p>Methods</p> <p>We tested for association between four linkage disequilibrium (LD)-tagging SNPs (rs2243123, rs2243151, rs668998, and rs17826053) in <it>IL12A </it>and asthma and allergy-related (serum total and allergen-specific IgE, and skin test reactivity [STR] to two common allergens) phenotypes in two samples: 417 Costa Rican children with asthma and their parents, and 470 families of 503 white children in the Childhood Asthma Management Program (CAMP). The analysis was conducted using the family-based association test (FBAT) statistic implemented in the PBAT program.</p> <p>Results</p> <p>Among Costa Rican children with asthma, homozygosity for the minor allele of each of two SNPs in <it>IL12A </it>(rs2243123 and rs2243151) was associated with increased risks of STR to American cockroach (P ≤ 0.03 for both SNPs), STR to German cockroach (P ≤ 0.01 for both SNPs), and having a positive IgE to German cockroach (P < 0.05 for both SNPs). Among children in CAMP, homozygosity for the minor allele of SNP rs2243151 in <it>IL12A </it>was inversely associated with STR to German cockroach (P = 0.03) and homozygosity for the minor allele of SNP rs17826053 in <it>IL12A </it>was associated with increased risks of STR to American cockroach (P = 0.01) and STR to German cockroach (P = 0.007). There was no significant association between any SNP in <it>IL12A </it>and asthma, STR to dust mite, or total IgE in Costa Rica or CAMP.</p> <p>Conclusion</p> <p>Our findings suggest that variants in <it>IL12A </it>influence cockroach allergy among children with asthma.</p
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Expression of SMARCD1 interacts with age in association with asthma control on inhaled corticosteroid therapy.
BackgroundGlobal gene expression levels are known to be highly dependent upon gross demographic features including age, yet identification of age-related genomic indicators has yet to be comprehensively undertaken in a disease and treatment-specific context.MethodsWe used gene expression data from CD4+ lymphocytes in the Asthma BioRepository for Integrative Genomic Exploration (Asthma BRIDGE), an open-access collection of subjects participating in genetic studies of asthma with available gene expression data. Replication population participants were Puerto Rico islanders recruited as part of the ongoing Genes environments & Admixture in Latino Americans (GALA II), who provided nasal brushings for transcript sequencing. The main outcome measure was chronic asthma control as derived by questionnaires. Genomic associations were performed using regression of chronic asthma control score on gene expression with age in years as a covariate, including a multiplicative interaction term for gene expression times age.ResultsThe SMARCD1 gene (SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily D member 1) interacted with age to influence chronic asthma control on inhaled corticosteroids, with a doubling of expression leading to an increase of 1.3 units of chronic asthma control per year (95% CI [0.86, 1.74], p = 6 × 10- 9), suggesting worsening asthma control with increasing age. This result replicated in GALA II (p = 3.8 × 10- 8). Cellular assays confirmed the role of SMARCD1 in glucocorticoid response in airway epithelial cells.ConclusionFocusing on age-dependent factors may help identify novel indicators of asthma medication response. Age appears to modulate the effect of SMARCD1 on asthma control with inhaled corticosteroids
A retrospective analysis of outcomes in low-Â and intermediate-high-risk pulmonary embolism patients managed on an ambulatory medical unit in the UK
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