433 research outputs found
Top Quarks as a Window to String Resonances
We study the discovery potential of string resonances decaying to
final state at the LHC. We point out that top quark pair production is a
promising and an advantageous channel for studying such resonances, due to
their low Standard Model background and unique kinematics. We study the
invariant mass distribution and angular dependence of the top pair production
cross section via exchanges of string resonances. The mass ratios of these
resonances and the unusual angular distribution may help identify their
fundamental properties and distinguish them from other new physics. We find
that string resonances for a string scale below 4 TeV can be detected via the
channel, either from reconstructing the semi-leptonic
decay or recent techniques in identifying highly boosted tops.Comment: 22 pages, 6 figure
Charged-Lepton Flavour Physics
This writeup of a talk at the 2011 Lepton-Photon symposium in Mumbai, India,
summarises recent results in the charged-lepton flavour sector. I review
searches for charged-lepton flavour violation, lepton electric dipole moments
and flavour-conserving CP violation. I also discuss recent progress in
tau-lepton physics and in the Standard Model prediction of the muon anomalous
magnetic moment.Comment: Presented at Lepton-Photon 2011, Mumbai, India; 23 pages, 14 figure
Genome\u2011wide diversity and runs of homozygosity in the \u201cBraque Fran\ue7ais, type Pyr\ue9n\ue9es\u201d dog breed
Objective: Braque Fran\uc3\ua7ais, type Pyr\uc3\ua9n\uc3\ua9es is a French hunting-dog breed whose origin is traced back to old pointing gun-dogs used to assist hunters in finding and retrieving game. This breed is popular in France, but seldom seen elsewhere. Despite the ancient background, the literature on its genetic characterization is surprisingly scarce. A recent study looked into the demography and inbreeding using pedigree records, but there is yet no report on the use of molecular markers in this breed. The aim of this work was to genotype a population of Braque Fran\uc3\ua7ais, type Pyr\uc3\ua9n\uc3\ua9es dogs with the high-density SNP array to study the genomic diversity of the breed. Results: The average observed (HO) and expected (HE) heterozygosity were 0.371 (\uc2\ub1 0.142) and 0.359 (\uc2\ub1 0.124). Effective population size (NE) was 27.5635 runs of homozygosity (ROH) were identified with average length of 2.16 MB. A ROH shared by 75% of the dogs was detected at the beginning of chromosome 22. Inbreeding coefficients from marker genotypes were in the range FIS= [- 0.127, 0.172]. Inbreeding estimated from ROH (FROH) had mean 0.112 (\uc2\ub1 0.023), with range [0.0526, 0.225]. These results show that the Braque Fran\uc3\ua7ais, type Pyr\uc3\ua9n\uc3\ua9es breed is a relatively inbred population, but with still sufficient genetic variability for conservation and genetic improvement
Averages of b-hadron, c-hadron, and tau-lepton properties as of 2018 Heavy Flavor Averaging Group (HFLAV)
This paper reports world averages of measurements of b-hadron, c-hadron, and
τ
-lepton properties obtained by the Heavy Flavour Averaging Group using results available through September 2018. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters,
C
P
violation parameters, parameters of semileptonic decays, and Cabibbo–Kobayashi–Maskawa matrix elements
Pediatric multiple sclerosis: update on diagnostic criteria, imaging, histopathology and treatment choices
Pediatric multiple sclerosis (MS) represents less than 5% of the MS population, but patients with pediatric-onset disease reach permanent disability at a younger age than adult onset patients. Accurate diagnosis at presentation and optimal long-term treatment is vital to mitigate ongoing neuroinflammation and irreversible neurodegeneration.
However, it may be difficult to early differentiate pediatric MS from acute disseminated
encephalomyelitis (ADEM) and neuromyelitis optica spectrum disorders (NMOSD) as they often have atypical presentation that differs from that of adult-onset MS. The
purpose of this review is to summarize the updated views on diagnostic criteria, imaging, histopathology and treatment choices
Permian high-temperature metamorphism in the Western Alps (NW Italy)
During the late Palaeozoic, lithospheric thinning in part of the Alpine realm caused high-temperature low-to-medium pressure metamorphism and partial melting in the lower crust. Permian metamorphism and magmatism has extensively been recorded and dated in the Central, Eastern, and Southern Alps. However, Permian metamorphic ages in the Western Alps so far are constrained by very few and sparsely distributed data. The present study fills this gap. We present U/Pb ages of metamorphic zircon from several Adria-derived continental units now situated in the Western Alps, defining a range between 286 and 266 Ma. Trace element thermometry yields temperatures of 580-890°C from Ti-in-zircon and 630-850°C from Zr-in-rutile for Permian metamorphic rims. These temperature estimates, together with preserved mineral assemblages (garnet-prismatic sillimanite-biotite-plagioclase-quartz-K-feldspar-rutile), define pervasive upper-amphibolite to granulite facies conditions for Permian metamorphism. U/Pb ages from this study are similar to Permian ages reported for the Ivrea Zone in the Southern Alps and Austroalpine units in the Central and Eastern Alps. Regional comparison across the former Adriatic and European margin reveals a complex pattern of ages reported from late Palaeozoic magmatic and metamorphic rocks (and relics thereof): two late Variscan age groups (~330 and ~300 Ma) are followed seamlessly by a broad range of Permian ages (300-250 Ma). The former are associated with late-orogenic collapse; in samples from this study these are weakly represented. Clearly, dominant is the Permian group, which is related to crustal thinning, hinting to a possible initiation of continental rifting along a passive margin
Search for neutral heavy leptons produced in decays
Weak isosinglet Neutral Heavy Leptons (νm) have been searched for using data collected by the DELPHI detector corresponding to 3.3 × 106 hadronic Z0 decays at LEP1. Four separate searches have been performed, for short-lived νm production giving monojet or acollinear jet topologies, and for long-lived νm giving detectable secondary vertices or calorimeter clusters. No indication of the existence of these particles has been found, leading to an upper limit for the branching ratio BR(Z0 → νmν̄) of about 1.3 × 10-6 at 95% confidence level for νm masses between 3.5 and 50 GeV/c2. Outside this range the limit weakens rapidly with the νm mass. The results are also interpreted in terms of limits for the single production of excited neutrinos. © Springer-Verlag 1997
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