SuperCDMS Cold Hardware Design

We discuss the current design of the cold hardware and cold electronics to be used in the upcoming SuperCDMS Soudan deployment. Engineering challenges associated with such concerns as thermal isolation, microphonics, radiopurity, and power dissipation are discussed, along with identifying the design changes necessary for SuperCDMS SNOLAB. The Cryogenic Dark Matter Search (CDMS) employs ultrapure 1-inch thick, 3-inch diameter germanium crystals operating below 50 mK in a dilution cryostat. These detectors give an ionization and phonon signal, which gives us rejection capabilities regarding background events versus dark matter signals.United States. Dept. of Energy (Grant DEAC02-76SF00515)United States. Dept. of Energy (Contract DC-AC02-07CH11359)National Science Foundation (U.S.) (Awards 0705052, 0902182, 1004714 and 0802575

Measurement of charged pion, kaon, and proton production in proton-proton collisions at s\sqrt{s} = 13 TeV

Transverse momentum spectra of charged pions, kaons, and protons are measured in proton-proton collisions at $\sqrt{s}$ = 13  TeV with the CMS detector at the LHC. The particles, identified via their energy loss in the silicon tracker, are measured in the transverse momentum range of $p_T \approx 0.1–1.7  GeV/c$ and rapidities $\vert y \vert < 1$. The $p_T$ spectra and integrated yields are compared to previous results at smaller $\sqrt{s}$ and to predictions of Monte Carlo event generators. The average $p_T$ increases with particle mass and charged particle multiplicity of the event. Comparisons with previous CMS results at $\sqrt{s}$ = 0.9, 2.76, and 7 TeV show that the average $p_T$ and the ratios of hadron yields feature very similar dependences on the particle multiplicity in the event, independently of the center-of-mass energy of the pp collision

Search for heavy gauge W' boson in events with an energetic lepton and large missing transverse momentum at s=13\sqrt{s } = 13 TeV

A search is presented for W′ bosons in events with an electron or muon and large missing transverse momentum, using proton–proton collision data at $\sqrt{s } = 13$ TeV collected with the CMS detector in 2015 and corresponding to an integrated luminosity of 2.3 $fb^{−1}$. No evidence of an excess of events relative to the standard model expectations is observed. For a W′ boson described by the sequential standard model, upper limits at 95% confidence level are set on the product of the production cross section and branching fraction and lower limits are established on the new boson mass. Masses below 4.1 TeV are excluded combining electron and muon decay channels, significantly improving upon the results obtained with the 8 TeV data. Exclusion limits at 95% confidence level on the product of the W′ production cross section and branching fraction are also derived in combination with the 8 TeV data. Finally, exclusion limits are set for the production of generic W′ bosons decaying into this final state using a model-independent approach

Combination of searches for heavy resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton–proton collisions at s\sqrt{s} = 8 and 13 TeV

A statistical combination of searches is presented for massive resonances decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton–proton collision data collected by the CMS experiment at the LHC. The data were taken at centre-of-mass energies of 8 and 13 TeV, corresponding to respective integrated luminosities of 19.7 and up to 2.7 $fb^{−1}$. The results are interpreted in the context of heavy vector triplet and singlet models that mimic properties of composite-Higgs models predicting W′ and Z′ bosons decaying to WZ, WW, WH, and ZH bosons. A model with a bulk graviton that decays into WW and ZZ is also considered. This is the first combined search for WW, WZ, WH, and ZH resonances and yields lower limits on masses at 95% confidence level for W′ and Z′ singlets at 2.3 TeV, and for a triplet at 2.4 TeV. The limits on the production cross section of a narrow bulk graviton resonance with the curvature scale of the warped extra dimension $\tilde{k}=0.5$, in the mass range of 0.6 to 4.0 TeV, are the most stringent published to date

Search for third-generation scalar leptoquarks and heavy right-handed neutrinos in final states with two tau leptons and two jets in proton-proton collisions at s=13\sqrt{s} = 13 TeV

A search is performed for third-generation scalar leptoquarks and heavy right-handed neutrinos in events containing one electron or muon, one hadronically decaying τ lepton, and at least two jets, using a $\sqrt{s} = 13$ TeV pp collision data sample corresponding to an integrated luminosity of 12.9 $fb^{-1}$ collected with the CMS detector at the LHC in 2016. The number of observed events is found to be in agreement with the standard model prediction. A limit is set at 95% confidence level on the product of the leptoquark pair production cross section and $β^2$, where β is the branching fraction of leptoquark decay to a τ lepton and a bottom quark. Assuming β = 1, third-generation leptoquarks with masses below 850 GeV are excluded at 95% confidence level. An additional search based on the same event topology involves heavy right-handed neutrinos, $N_R$, and right-handed W bosons, $W_R$, arising in a left-right symmetric extension of the standard model. In this search, $W_R$ bosons are assumed to decay to a tau lepton and $N_R$ followed by the decay of the $N_R$ to a tau lepton and an off-shell $W_R$ boson. Assuming the mass of the right-handed neutrino to be half of the mass of the right-handed W boson, $W_R$ boson masses below 2.9 TeV are excluded at 95% confidence level. These results improve on the limits from previous searches for third-generation leptoquarks and heavy right-handed neutrinos with τ leptons in the final state

Search for supersymmetry in pp collisions at s\sqrt{s} = 13 tev in the single-lepton final state using the sum of masses of large-radius jets

Results are reported from a search for supersymmetric particles in proton-proton collisions in the final state with a single lepton, multiple jets, including at least one b-tagged jet, and large missing transverse momentum. The search uses a sample of proton-proton collision data at $\sqrt{s}$ = 13 TeV recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9  $fb^{−1}$. The observed event yields in the signal regions are consistent with those expected from standard model backgrounds. The results are interpreted in the context of simplified models of supersymmetry involving gluino pair production, with gluino decay into either on- or off-mass-shell top squarks. Assuming that the top squarks decay into a top quark plus a stable, weakly interacting neutralino, scenarios with gluino masses up to about 1.9 TeV are excluded at 95% confidence level for neutralino masses up to about 1 TeV

Search for dark matter produced in association with heavy-flavor quark pairs in proton-proton collisions at s\sqrt{s} = 13 TeV

A search is presented for an excess of events with heavy-flavor quark pairs ($t\overline{t}$ and $b\overline{b}$) and a large imbalance in transverse momentum in data from proton–proton collisions at a center-of-mass energy of 13TeV. The data correspond to an integrated luminosity of 2.2 $fb^{−1}$ collected with the CMS detector at the CERN LHC. No deviations are observed with respect to standard model predictions. The results are used in the first interpretation of dark matter production in $t\overline{t}$ and $b\overline{b}$ final states in a simplified model. This analysis is also the first to perform a statistical combination of searches for dark matter produced with different heavy-flavor final states. The combination provides exclusions that are stronger than those achieved with individual heavy-flavor final states

Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis

Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al

Search for dark matter produced with an energetic jet or a hadronically decaying W or Z boson at s=13\sqrt{s}=13 TeV

A search for dark matter particles is performed using events with large missing transverse momentum, at least one energetic jet, and no leptons, in proton-proton collisions at $\sqrt{s}=13$ TeV collected with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 12.9 $fb^{−1}$. The search includes events with jets from the hadronic decays of a W or Z boson. The data are found to be in agreement with the predicted background contributions from standard model processes. The results are presented in terms of simplified models in which dark matter particles are produced through interactions involving a vector, axial-vector, scalar, or pseudoscalar mediator. Vector and axial-vector mediator particles with masses up to 1.95 TeV, and scalar and pseudoscalar mediator particles with masses up to 100 and 430 GeV respectively, are excluded at 95% confidence level. The results are also interpreted in terms of the invisible decays of the Higgs boson, yielding an observed (expected) 95% confidence level upper limit of 0.44 (0.56) on the corresponding branching fraction. The results of this search provide the strongest constraints on the dark matter pair production cross section through vector and axial-vector mediators at a particle collider. When compared to the direct detection experiments, the limits obtained from this search provide stronger constraints for dark matter masses less than 5, 9, and 550 GeV, assuming vector, scalar, and axial-vector mediators, respectively. The search yields stronger constraints for dark matter masses less than 200 GeV, assuming a pseudoscalar mediator, when compared to the indirect detection results from Fermi-LAT