6,401 research outputs found

    AFBA_{FB} as a discovery tool for ZZ^\prime bosons at the LHC

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    The Forward-Backward Asymmetry (AFB) in ZZ^\prime physics is commonly only perceived as the observable which possibly allows one to interpret a ZZ^\prime signal by distinguishing different models of such (heavy) spin-1 bosons. In this article, we examine the potential of AFB in setting bounds on or even discovering a ZZ^\prime at the Large Hadron Collider (LHC) and show that it might be a powerful tool for this purpose. We analyze two different scenarios: ZZ^\primes with a narrow and wide width, respectively. We find that in both cases AFB can complement the cross section in accessing ZZ^\prime signals.Comment: arXiv admin note: substantial text overlap with arXiv:1503.0267

    Phenomenology of the minimal B-L extension of the Standard Model

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    We present the Large Hadron Collider (LHC) discovery potential in the ZZ' and heavy neutrino sectors of a U(1)BLU(1)_{B-L} enlarged Standard Model also encompassing three heavy Majorana neutrinos. This model exhibits novel signatures at the LHC, the most interesting arising from a ZZ' decay chain involving heavy neutrinos, eventually decaying into leptons and jets. In particular, this signature allows one to measure the ZZ' and heavy neutrino masses involved. In addition, over a large region of parameter space, the heavy neutrinos are rather long-lived particles producing distinctive displaced vertices that can be seen in the detectors. Lastly, the simultaneous measurement of both the heavy neutrino mass and decay length enables an estimate of the absolute mass of the parent light neutrino. For completeness, we will also compare the LHC and a future Linear Collider (LC) discovery potentials.Comment: 4 pages, no figures. LaTeX. Talk given at "The 2009 Europhysics Conference on High Energy Physics", Krakow, Poland, July 16-22, 200

    A smoking gun signature of the 3HDM

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    We analyse new signals of a 3-Higgs Doublet Model (3HDM) at the Large Hadron Collider (LHC) where only one doublet acquires a Vacuum Expectation Value (VEV), preserving a Z2Z_2 parity. The other two doublets are \textit{inert} and do not develop a VEV, leading to a \textit{dark scalar sector} controlled by Z2Z_2, with the lightest CP-even dark scalar H1H_1 being the Dark Matter (DM) candidate. This leads to the loop induced decay of the next-to-lightest scalar, H2H1ˉH_2 \to H_1 \ell \bar \ell (=e,μ\ell =e,\mu), mediated by both dark CP-odd neutral and charged scalars. This is a smoking-gun signal of the 3HDM since it is not allowed in the 2-Higgs Doublet Model (2HDM) with one inert doublet and is expected to be important when H2H_2 and H1H_1 are close in mass. In practice, this signature can be observed in the cascade decay of the SM-like Higgs boson, hH1H2H1H1ˉh\to H_1 H_2\to H_1 H_1 \ell \bar \ell into two DM particles and di-leptons or hH2H2H1H1ˉˉh\to H_2 H_2\to H_1 H_1 \ell \bar \ell \ell \bar \ell into two DM particles and four-leptons, where hh is produced from gluon-gluon Fusion. In order to test the feasibility of these channels at the LHC, we devise some benchmarks, compliant with collider, DM and cosmological data, for which the interplay between these production and decay modes is discussed. In particular, we show that the resulting detector signatures, \Et \ell \bar \ell or \Et \ell \bar \ell \ell \bar \ell, with the invariant mass of ˉ \ell \bar \ell pairs much smaller than mZm_Z, can potentially be extracted already from Run 3 data and at the High-Luminosity phase of the LHC.Comment: 27 pages, 13 figures. arXiv admin note: text overlap with arXiv:1712.0959

    Exploring Sensitivity to NMSSM Signatures with Low Missing Transverse Energy at the LHC

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    We examine scenarios in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), where pair-produced squarks and gluinos decay via two cascades, each ending in a stable neutralino as Lightest Supersymmetric Particle (LSP) and a Standard Model (SM)-like Higgs boson, with mass spectra such that the missing transverse energy, ETmissE_{T}^{\text{miss}}, is very small. Performing two-dimensional parameter scans and focusing on the hadronic HbbˉH\rightarrow b\bar{b} decay giving a bbˉbbˉ+ETmissb\bar{b}b\bar{b} + E_{T}^{\text{miss}} final state we explore the sensitivity of a current LHC general-purpose jets+ETmissE_{T}^{\text{miss}} analysis to such scenarios.Comment: 17 pages, 17 figures, 6 table

    Tensor analyzing powers for Li7 breakup

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    Differential cross sections and T20 and 20TT analyzing powers have been measured for 70 MeV Li7 breakup into the particle plus triton channel, on a Sn120 target. Measurements were made for both continuum breakup and sequential breakup via the 4.63 MeV state in Li7. The T20 data for the continuum breakup do not agree with a semiclassical Coulomb model, indicating that the breakup at small angles does not proceed solely via a Coulomb force. The data generally show a somewhat better agreement with continuum discretized coupled channels calculations, indicating the importance of the nuclear force and channel coupling in the reaction mechanism. © 1995 The American Physical Society

    Run 2 Upgrades to the CMS Level-1 Calorimeter Trigger

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    The CMS Level-1 calorimeter trigger is being upgraded in two stages to maintain performance as the LHC increases pile-up and instantaneous luminosity in its second run. In the first stage, improved algorithms including event-by-event pile-up corrections are used. New algorithms for heavy ion running have also been developed. In the second stage, higher granularity inputs and a time-multiplexed approach allow for improved position and energy resolution. Data processing in both stages of the upgrade is performed with new, Xilinx Virtex-7 based AMC cards.Comment: 10 pages, 7 figure

    Les Houches 2011: Physics at TeV Colliders New Physics Working Group Report

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    We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our report includes new agreements on formats for interfaces between computational tools, new tool developments, important signatures for searches at the LHC, recommendations for presentation of LHC search results, as well as additional phenomenological studies.Comment: 243 pages, report of the Les Houches 2011 New Physics Group; fix three figure

    New Physics at the LHC. A Les Houches Report: Physics at TeV Colliders 2009 - New Physics Working Group

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    We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. First, are presented various tools developed to measure new particle masses in scenarios where all decays include an unobservable particle. Second, various aspects of supersymmetric models are discussed. Third, some signatures of models of strong electroweak symmetry are discussed. In the fourth part, a special attention is devoted to high mass resonances, as the ones appearing in models with warped extra dimensions. Finally, prospects for models with a hidden sector/valley are presented. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 8-26 June, 2009).Comment: 189 page

    Defining the functional role of NaV1.7 in human nociception

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    Loss-of-function mutations in NaV1.7 cause congenital insensitivity to pain (CIP); this voltage-gated sodium channel is therefore a key target for analgesic drug development. Utilizing a multi-modal approach, we investigated how NaV1.7 mutations lead to human pain insensitivity. Skin biopsy and microneurography revealed an absence of C-fiber nociceptors in CIP patients, reflected in a reduced cortical response to capsaicin on fMRI. Epitope tagging of endogenous NaV1.7 revealed the channel to be localized at the soma membrane, axon, axon terminals, and the nodes of Ranvier of induced pluripotent stem cell (iPSC) nociceptors. CIP patient-derived iPSC nociceptors exhibited an inability to properly respond to depolarizing stimuli, demonstrating that NaV1.7 is a key regulator of excitability. Using this iPSC nociceptor platform, we found that some NaV1.7 blockers undergoing clinical trials lack specificity. CIP, therefore, arises due to a profound loss of functional nociceptors, which is more pronounced than that reported in rodent models, or likely achievable following acute pharmacological blockade

    L1 track finding for a time multiplexed trigger

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    At the HL-LHC, proton bunches will cross each other every 25. ns, producing an average of 140 pp-collisions per bunch crossing. To operate in such an environment, the CMS experiment will need a L1 hardware trigger able to identify interesting events within a latency of 12.5. μs. The future L1 trigger will make use also of data coming from the silicon tracker to control the trigger rate. The architecture that will be used in future to process tracker data is still under discussion. One interesting proposal makes use of the Time Multiplexed Trigger concept, already implemented in the CMS calorimeter trigger for the Phase I trigger upgrade. The proposed track finding algorithm is based on the Hough Transform method. The algorithm has been tested using simulated pp-collision data. Results show a very good tracking efficiency. The algorithm will be demonstrated in hardware in the coming months using the MP7, which is a μTCA board with a powerful FPGA capable of handling data rates approaching 1. Tb/s.This project has received funding from the European Union׳s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 317446
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