LHCb Semileptonic Asymmetry

A recent LHCb measurement of the CP violating flavour specific asymmetry in $B_s^0$ decays, \asls, is presented. This measurement is based on a data sample corresponding to an integrated luminosity of 1 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ $=$ 7 TeV, collected during the 2011 run of the LHC. The result is \asls = (-0.24 \pm 0.54_{\rm stat} \pm 0.33_{\rm syst})\times 10^{-2}, which is the most precise measurement of this quantity to date and agrees with the Standard Model prediction.}Comment: To appear in the proceedings of Beauty 201

LHCb PDF measurements

The LHCb experiment covers a unique region of acceptance at forward rapidities in the high energy proton-proton collisions of the LHC. This means that measurements of particle production in LHCb are directly sensitive to the parton distribution functions at low Bj\"orken-$x$ values. Several measurements of inclusive $W$ and $Z/\gamma^{\ast}$ production with the Run-I dataset are reported in these proceedings. Further measurements of $W$ and $Z/\gamma^{\ast}$ production in association with inclusive jets and $b$- and $c$-tagged jets are also reported.Comment: On behalf of the LHCb collaboration. In Proceedings of the Third Annual Large Hadron Collider Physics Conference LHCP15, Aug. 31-Sept 5, 2015 St. Petersburg, Russi

Prospects for improving the LHC W boson mass measurement with forward muons

Measurements of the $W$ boson mass are planned by the ATLAS and CMS experiments, but for the time being, these may be unable to compete with the current world average precision of 15~MeV, due to uncertainties in the PDFs. We discuss the potential of a measurement by the LHCb experiment based on the charged lepton transverse momentum $p_T^{\ell}$ spectrum in $W \to \mu\nu$ decays. The unique forward acceptance of LHCb means that the PDF uncertainties would be anti-correlated with those of $p_T^{\ell}$ based measurements by ATLAS and CMS. We compute an average of ATLAS, CMS and LHCb measurements of $m_W$ from the $p_T^{\ell}$ distribution. Considering PDF uncertainties, this average is a factor of 1.3 more precise than an average of ATLAS and CMS alone. Despite the relatively low rate of $W$ production in LHCb, we estimate that with the Run-II dataset, a measurement could be performed with sufficient experimental precision to exploit this anti-correlation in PDF uncertainties. The modelling of the lepton-pair transverse momentum distribution in the neutral current Drell-Yan process could be a limiting factor of this measurement and will deserve further studies.Comment: 10 pages, 3 figures, submitted to EPJ

Flux-driven Josephson parametric amplifier for sub-GHz frequencies fabricated with side-wall passivated spacer junction technology

We present experimental results on a Josephson parametric amplifier tailored for readout of ultra-sensitive thermal microwave detectors. In particular, we discuss the impact of fabrication details on the performance. We show that the small volume of deposited dielectric materials enabled by the side-wall passivated spacer niobium junction technology leads to robust operation across a wide range of operating temperatures up to 1.5 K. The flux-pumped amplifier has gain in excess of 20 dB in three-wave mixing and its center frequency is tunable between 540 MHz and 640 MHz. At 600 MHz, the amplifier adds 105 mK $\pm$ 9 mK of noise, as determined with the hot/cold source method. Phase-sensitive amplification is demonstrated with the device

A simple method to determine charge-dependent curvature biases in track reconstruction in hadron collider experiments

A new data-driven method, using $Z \rightarrow \mu^+ \mu^-$ decays, is proposed to correct for charge-dependent curvature biases in spectrometer experiments at hadron colliders. The method is studied assuming a detector with a "forward-spectrometer" geometry similar to that of the LHCb experiment, and is shown to reliably control several simplified detector mis-alignment configurations. The applicability of the method for use in measurements of precision electroweak observables is evaluated.Comment: 16 pages, 10 figure

Cosmic Neutrino Last Scattering Surface

Neutrinos decoupled from the rest of the cosmic plasma when the Universe was less than one second old, far earlier than the photons which decoupled at t=380,000 years. Surprisingly, though, the last scattering surface of the neutrinos is much closer to us than that of the photons. Here we calculate the properties of the last scattering surfaces of the three species of neutrinos.Comment: Important reference to earlier work of Bisnovatyi-Kogan and Seidov added, and mis-spelling of Opher reference correcte

Tensin2 Is a Novel Diagnostic Marker in GIST, Associated with Gastric Location and Non-Metastatic Tumors

GIST is a rare soft tissue sarcoma, for which KIT and DOG1 are used as highly sensitive diagnostic markers. Other diagnostic markers include CD34, protein kinase C θ, deficiency of succinate dehydrogenase complex subunit B, carbonic anhydrase II, and type I insulin-like growth factor receptor. We investigated the role of TNS2 as a diagnostic biomarker by using immunohistochemistry in 176 GISTs and 521 other sarcomas. All GISTs expressed TNS2, with intermediate or high expression in 71.4% of samples. The majority (89.8%) of other sarcomas were negative for TNS2, and intermediate to strong staining was only seen in 2.9% of samples. Strong TNS2 staining was associated with gastric location (gastric 52.8% vs. non-gastric 7.2%; p < 0.001), absence of metastases (non-metastatic tumors 44.3% vs. metastatic tumors 5.9%; p = 0.004), female sex (female 45.9% vs. male 33.8%; p = 0.029), and tumors of lower risk categories (very low or low 46.9% vs. intermediate 51.7% vs. high 29.0%; p = 0.020). TNS2 expression did not correlate with overall survival or metastasis-free survival. No associations between TNS2 expression and KIT/PDGFRA mutation status, tumor size, mitotic count, or age of the patient were detected. The results provide conclusive evidence for the value of TNS2 as a sensitive and specific diagnostic biomarker for GIST