Constraints on Higgs effective couplings in HννˉH\nu \bar{\nu} production of CLIC at 380 GeV

The potential of the $e^+e^-\to\nu \bar{\nu} H$ process in the first stage of CLIC considering center of mass energy of 380 GeV and assuming the baseline integrated luminosity of 500 fb$^{-1}$ is examined to probe CP conserving dimension-six operators in a model-independent Standard Model effective field theory framework. In the analysis, a detailed fast simulation on $e^+e^-\to\nu \bar{\nu} H$ signal processes and dominant backgrounds are performed including parton showering with PYTHIA and detector simulation based on ILD type detector with DELPHES in MadGraph. The obtained best limits on the $\bar{c}_{HB}$, $\bar{c}_{W}=- \bar{c}_{B}$ and $\bar{c}_{HW}$ are $[-4.82;1.53]\times10^{-2}$, $[-5.11;4.13]\times10^{-3}$ and $[-6.58;5.55]\times10^{-3}$, respectively.Comment: 13 pages, 6 figures, published versio

Electron muon identification by atmospheric shower and electron beam in a new concept of an EAS detector

We present results demonstrating the time resolution and $\mu$/e separation capabilities with a new concept of an EAS detector capable for measurements of cosmic rays arriving with large zenith angles. This kind of detector has been designed to be a part of a large area (several square kilometers) surface array designed to measure Ultra High Energy (10-200 PeV) $\tau$ neutrinos using the Earth-skimming technique. A criteria to identify electron-gammas is also shown and the particle identification capability is tested by measurements in coincidence with the KASKADE-GRANDE experiment in Karlsruhe, Germany.Comment: accepted by Astrophysical Journal on January 12 2015, 16 pages 3 Figure

Top quark FCNC couplings at future circular hadron electron colliders

A study of single top quark production via flavor changing neutral current interactions at $tq\gamma$ vertices is performed at future circular hadron electron collider. The signal cross sections for the processes $e^{-}p\to e^{-}W^{\pm}q+X$ and $e^{-}p\to e^{-}W^{\pm}bq+X$ in the collision of electron beam with energy $E_e=$ 60 GeV and proton beam with energy $E_p=$ 50 TeV are calculated. In the analysis, the invariant mass distributions of three jets reconstructing top quark mass, requiring one b-tagged jet and other two jets reconstructing the $W$ mass are used to count signal and background events after all selection cuts. The upper limits on the anomalous flavor changing neutral current $tq\gamma$ couplings are found to be $\lambda_q <$ 0.01 at future circular hadron electron collider for $L_{int}=100$ fb$^{-1}$ with the fast simulation of detector effects. Signal significance depending on the couplings $\lambda_q$ is analyzed and an enhanced sensitivity is found to the branching ratio BR($t\to q\gamma$) at the future circular hadron electron collider when compared to the current experimental results.Comment: 11 pages, 4 Figures, 4 Tables, to appear in Phys. Rev.

Probing the electromagnetic properties of the neutrinos at future lepton colliders

In this study, we explore the non-standard $\nu\bar{\nu}\gamma \gamma$ couplings parametrized by dimension-seven operators via $e^{+}e^{-} \to \nu\bar{\nu}\gamma$ process at the FCC-ee/CEPC and $\mu^{+}\mu^{-}\to\nu\bar{\nu}\gamma$ process at the Muon Colliders. For the detailed Monte Carlo simulation, all signal and relevant background events are produced within the framework of Madgraph where non-standard $\nu\bar{\nu}\gamma \gamma$ couplings are implemented. After passing through Pythia for parton showering and hadronization, detector effects are included via tuned corresponding detector cards for each collider in Delphes. Projected sensitivities on $\nu\bar{\nu}\gamma \gamma$ couplings are obtained at a 5$\sigma$ confidence level without and with $5\%$ systematic uncertainties for the FCC-ee/CEPC and the Muon Colliders, showcasing the complementarity between lepton colliders. Our best limit on the anomalous $\nu\bar{\nu}\gamma \gamma$ couplings even with 5\% systematic uncertainties for muon collider with $\sqrt{s}=10$ TeV and $L_{int}=3$ ab$^{-1}$ are found to be thirteen orders of magnitude stronger than the upper bound obtained from rare decay $Z\to\gamma\gamma\nu\bar{\nu}$ analysis using LEP data.Comment: 17 pages, 9 figure

Sensitivity of anomalous quartic gauge couplings via tri-photon production at FCC-hh

A direct investigation of the self-couplings of gauge bosons, completely described by the non-Abelian gauge symmetry of the Standard Model, is extremely valuable in understanding the gauge structure of the SM. Any deviation from the SM predictions on gauge boson self-coupling is to give a hint at the existence of a new physics beyond the SM, which is defined with a modification of the self-interactions using an effective field theory approach. In this paper, we present a detailed Monte Carlo study searching for anomalous quartic gauge dimension-8 couplings related to $\gamma\gamma\gamma\gamma$ and $\gamma\gamma\gamma Z$ vertices at the future hadron-hadron collider (FCC-hh) via tri-photon production at a 100 TeV center of mass energy with an integrated luminosity L$_{int}$=30 ab$^{-1}$. Events that have been parton showered and include detector effects are analyzed with a Toolkit for Multivariate Data Analysis (TMVA) using a boosted decision tree to help distinguish between signal and background events to achieve the best sensitivities on anomalous quartic gauge couplings. Our obtained results reveal that the limits on anomalous quartic gauge couplings $f_{T8}/\Lambda^{4}$ and $f_{T9}/\Lambda^{4}$ at 95\% C.L. without systematic errors are about three orders of magnitude stronger compared to the best current experimental limits reported by the ATLAS collaboration at the LHC. Considering a realistic systematic uncertainty such as 10\% from possible experimental sources, our obtained limits of anomalous quartic couplings get worse by about one order of magnitude compared to those without systematic uncertainty but are still two orders of magnitude better than those recently reported by ATLAS.Comment: 18 pages, 7 figures, some typos corrected and reference adde

Search for the electromagnetic properties of the neutrinos at the HL-LHC and the FCC-hh

The $\nu\bar{\nu}\gamma \gamma$ couplings parametrized with the non-standard dimension-seven operators defined by the Effective Field Theory framework are investigated through the process $pp\to \nu\bar{\nu}\gamma$ at the High Luminosity-LHC and the Future Circular proton-proton Collider. The effective Lagrangian of $\nu\bar{\nu}\gamma \gamma$ couplings is implemented into FeynRules to generate a UFO module inserted into Madgraph to generate both background and signal events. These events are then passed through Pythia 8 for parton showering and Delphes to include realistic detector effects. The sensitivities on $\nu\bar{\nu}\gamma \gamma$ couplings are obtained at $95\%$ confidence level. We show that the analysis of the signal emerging from the process $pp\to \nu\bar{\nu}\gamma$ allows to improve constraints on $\nu\bar{\nu}\gamma \gamma$ couplings given by the LEP collaboration.Comment: 14 pages, 6 figures, 2 tables, version accepted for publication in Physics Letters

Q2 dependence of the S11(1535) photocoupling and evidence for a P-wave resonance in η electroproduction

New cross sections for the reaction ep→e′ηp are reported for total center-of-mass energy W=1.5-2.3 GeV and invariant squared momentum transfer Q2=0.13-3.3 GeV2. This large kinematic range allows the extraction of new information about response functions, photocouplings, and ηN coupling strengths of baryon resonances. A sharp structure is seen at W~1.7 GeV. The shape of the differential cross section is indicative of the presence of a P-wave resonance that persists to high Q2. Improved values are derived for the photocoupling amplitude for the S11(1535) resonance. The new data greatly expand the Q2 range covered, and an interpretation of all data with a consistent parametrization is provided