We propose to utilize the polarization information of the $Z$ bosons in $ZZ$ production, via the gluon-gluon fusion process $gg\to ZZ$, to probe the $Zt\bar{t}$ gauge coupling. The contribution of longitudinally polarized $Z$ bosons is sensitive to the axial-vector component ($a_t$) of the $Zt\bar{t}$ coupling. We demonstrate that the angular distribution of the charged lepton from $Z$ boson decays serves well for measuring the polarization of $Z$ bosons and the determination of $a_t$. We show that $ZZ$ production via the $gg\to ZZ$ process complement to $Zt\bar{t}$ and $tZj$ productions in measuring the $Zt\bar{t}$ coupling at hadron colliders.
We describe different possibilities to probe the BFKL dynamics at hadronic colliders, namely Mueller-Navelet jet, and jet gap jet events. We also discuss briefly the jet veto measurement as performed by the ATLAS collaboration at the LHC.
Potential of the LHeC for probing small x(g) region via c\bar{c} and b\bar{b} production have been investigated. Obtained results clearly show the advantage of gamma-p collider option. Measurement of x(g) down to 3\times10^{-6} seems to be reachable which is two order smaller than HERA coverage.
A feasibility study of a 500-GeV linear collider is presented for mSUGRA models in co-annihilation region. We find an active mask is critical to suppress $e^+ e^- \to e^+ e^- τ^+ τ^-$ events to probe the models.
We propose a novel idea for probing the Higgs boson couplings through the measurement of hadronic event shape distributions in the decay of the Higgs boson at lepton colliders. The method provides a unique test of the Higgs boson couplings and of QCD effects in the decay of the Higgs boson. It can be used to probe the Yukawa couplings of the light quarks and to further test the mechanism of electroweak symmetry breaking. From a case study for the proposed Circular Electron-Positron Collider, assuming a hypothesis of SM-like theory, light-quark couplings with a strength greater than 9% of the b…
Several new physics scenarios, motivated e.g. by dark matter, feature new electroweakly charged states where the lightest particle in the multiplet is stable and neutral. In such cases direct searches at LHC are notoriously difficult, while electroweak precision tests both at hadron and lepton colliders offer the possibility to indirectly probe those states. In this work, we assess the sensitivity of the high-luminosity phase of the LHC on new electroweak multiplets via the modification of neutral and charged Drell-Yan processes, and compare the reach of future hadron and lepton colliders pres…
Identification of charmonium states at hadron colliders has mostly been limited to leptonic decays of the J/ψ. In this paper we present and algorithm to identify hadronic decays of charmonium states (J/ψ, ψ(2S), χ_{c0,1,2}) which make up the large majority of all decays. The algorithm is able to identify hadronic $J/ψ$ decays with an efficiency of 36\% while suppressing a background of quark and gluon jets by a factor 100.
We explore the ability of current and future dark matter and collider experiments in probing anomalous magnetic moment of the muon, $(g-2)_μ$, within the Minimal Supersymmetric Standard Model (MSSM). We find that the latest PandaX-II/LUX-2016 data gives a strong constraint on parameter space that accommodates the $(g-2)_μ$ within $2σ$ range, which will be further excluded by the upcoming XENON-1T (2017) experiment. We also find that a 100 TeV $pp$ collider can cover most of our surviving samples that satisfy DM relic density within $3σ$ range through $Z$ or $h$ resonant effect by searching for…
We propose a method to probe the coupling of the Higgs to strange quarks by tagging strange jets at future lepton colliders. For this purpose we describe a jet-flavor observable, $J_F$, that is correlated with the flavor of the quark associated with the hard part of the jet. Using this variable, we set up a strangeness tagger aimed at studying the decay $h\to s\bar{s}$. We determine the sensitivity of our method to the strange Yukawa coupling, and find it to be of the order of the standard-model expectation.
Rare B hadron decays provide an excellent test bench for the Standard Model and can probe new physics models. We review the experimental progress of the searches for rare leptonic B decays ($b\rightarrow \ell^+ \ell^-$ and $b\rightarrow s \ell^+ \ell^-$) at LHC and Tevatron experiments.
The description of the QCD dynamics in the kinematical range which will be probed in the future electron - hadron colliders is still an open question. Although phenomenological studies indicate that the gluon number fluctuations, which are related to discreteness in the QCD evolution, are negligible at HERA, the magnitude of these effects for the next generation of colliders still should be estimated. In this paper we investigate inclusive and diffractive $ep$ observables considering a model for the physical scattering amplitude which describes the HERA data. Moreover, we estimate, for the fir…
Recent experimental and theoretical results presented in the working group "Parton densities from DIS and hadron colliders to LHC" at the DIS2010 workshop are summarized in this contribution.
Possible anomalous top-quark couplings induced by SU(2) x U(1) gauge-invariant dimension-6 effective operators were studied in the process of t t-bar productions and decays at polarized gamma gamma colliders. Two CP-violating asymmetries, a linear-polarization asymmetry and a circular-polarization asymmetry, were computed including both non-standard [t t-bar gamma] and [gamma gamma H] couplings. An optimal-observable analysis for the process gamma gamma --> t t-bar --> l^{+-} ... was performed in order to estimate the precision for determination of all relevant non-standard couplings, includin…
In this contribution we review the status of inclusive jet cross sections at hadron colliders in perturbative QCD, studying in particular the renormalisation and factorisation scale dependence of the one-jet inclusive cross section at NNLO.
We review the methods which have been proposed for measuring masses of new particles at the Large Hadron Collider paying particular attention to the kinematical techniques suitable for extracting mass information when invisible particles are expected.
Two-particle azimuthal angle correlations have been proposed to be one of the most direct and sensitive probes to access the underlying gluon dynamics involved in hard scatterings. In anticipation of an Electron-Ion Collider (EIC), detailed studies of dihadron correlation measurements in electron-proton and electron-ion collisions at an EIC have been performed. The impact of such measurements on the understanding of the different gluon distribution functions, as a clean signature for gluon saturation and to constrain saturation models further, has been explored. It is shown that dihadron corre…
The Monte Carlo integrator HAWK provides precision predictions for Higgs production at hadron colliders in vector-boson fusion and Higgs strahlung, i.e. in production processes where the Higgs boson is Attached to WeaK bosons. The fully differential predictions include the full QCD and electroweak next-to-leading-order corrections. Results are computed as integrated cross sections and as binned distributions for important hadron-collider observables.
We define a CP-asymmetric observable that is sensitive to CP-violating interactions in the gauge-boson sector. We illustrate the utility of this observable by studying how well the LHC can measure the coefficient of a particular dimension-six WWZ operator. We find that sensitivity at the 10^{-3} level is possible at the LHC with 100 fb^{-1} of integrated luminosity, which would greatly exceed the sensitivity achieved at LEP, and would rival or may even better the indirect sensitivities inferred from related operators constrained by electric dipole moment experiments.
I discuss strategies for probing CP properties in the top quark system at $e^-e^+$ and hadron Colliders. The magnitudes of CP violation effects predicted by various models are reviewed. I also discuss the potential of various current and future colliders in measuring the CP asymmetry associated with the productions and/or decays of the top quarks.
We present pseudorapidity and transverse momentum distributions for the cross section for the production of the lightest neutral Higgs boson in association with a high-p_T hadronic jet, calculated in the framework of the minimal supersymmetric standard model (MSSM). We discuss the theoretical predictions for the differential cross sections at the Large Hadron Collider and the Tevatron for the most common benchmark scenarios.
Current absolute branching fractions of $Λ_c^+$ and $D_s^+$ mesons are limiting the determination of important measurements. They have only been measured at $e^+e^-$ colliders. Here techniques for measuring them at hadron colliders are discussed. The precision determination of $Λ_c^+\to p K^-π^+$ seems possible with current data, however the corresponding determination of $D_s^+\to K^+K^-π^+$ will require more integrated luminosity.
We assess the sensitivity of the LHC, its high energy upgrade, and a prospective 100 TeV hadronic collider to the Dirac Yukawa coupling of the heavy neutrinos in left-right symmetric models (LRSMs). We focus specifically on the trilepton final state in regions of parameter space yielding prompt decays of the right-handed gauge bosons ($W_R$) and neutrinos ($N_R$). In the minimal LRSM, the Dirac Yukawa couplings are completely fixed in terms of the mass matrices for the heavy and light neutrinos. In this case, the trilepton signal provides a direct probe of the Dirac mass term for a fixed $W_R$…
The next-generation high-energy facilities, the CERN Large Hadron Collider (LHC) and the prospective $e^+e^-$ International Linear Collider (ILC), are expected to unravel new structures of matter and forces from the electroweak scale to the TeV scale. In this report we review the complementary role of LHC and ILC in drawing a comprehensive and high-precision picture of the mechanism breaking the electroweak symmetries and generating mass, and the unification of forces in the frame of supersymmetry.
We sketch some of our recent studies on probing strongly interacting electroweak symmetry breaking mechanism at high energy colliders such as the CERN LHC and the future e(+)e(-) linear collider. The study includes both model-dependent and model-independent probes.
The theoretical structure of the Higgs sector of the Minimal Supersymmetric Standard Model (MSSM) is briefly described. An outline of Higgs phenomenology at future lepton colliders is presented, and some opportunities for probing the physics of the MSSM Higgs sector at an e-e- collider are considered.
In this report, we give the Balitsky Fadin Kuraev Lipton formalism for jet gap jet events at hadronic colliders. We also discuss the case where in addition at least one proton is intact in the final state in diffractive events.
We examine anomalous ZZH and gammaZH interactions in the process e+e- -> HZ followed by Z -> l+l- at a linear collider. We study the effects of beam polarization, both longitudinal and transverse, in probing these anomalous couplings. We study various correlations constructed out of the initial and final state lepton momenta and the spins of electron and positron. We evaluate the sensitivity of these observables to probe anomalous couplings at the linear collider.
Anomalous chromomagnetic and chromoelectric dipole moments of the top quark may arise from various high scale theories. We carry out a model independent study of such interactions focusing on the limits that can be obtained from current Tevatron data and the improvements that may be possible at the LHC or at a future Linear Collider.
In this review we demonstrate physics potential of a photon linear collider by studying the neutral Higgs-boson sector of the MSSM in which interesting CP-violating Higgs mixing could arise via radiative corrections.
We briefly review the recent developments of probing the electroweak symmetry breaking mechanism at high energy colliders such as the CERN LEP2, the Fermilab Tevatron, the CERN LHC and the e(+)e(-) linear colliders. Both weakly interacting and strongly interacting electroweak symmetry breaking mechanisms are concerned.
The International Linear Collider (ILC) will be able to precisely measure the electroweak couplings of the top in e+e- -> tt~. We compare the limits which can be achieved at the ILC with those which can be obtained in tt~gamma$ and tt~Z production at the Large Hadron Collider (LHC).
We describe how to probe new physics through large CP violation effects and non--standard Z-t-t couplings via the scattering process e^-e^+ -> t tbar. [Talk presented at the Workshop on Physics and Experiments with Linear $e^+e^-$ Colliders, Waikoloa, Hawaii, 26-30 April 1993.]
The investigation of lepton-hadron and photon-hadron collisions at TeV scale is crucial both to clarify the strong interaction dynamics from nuclei to quark-parton level and for adequate interpretation of experimental data from future hadron colliders (LHC and VLHC). In this presentation different TeV scale lepton-hadron and photon-hadron collider proposals (such as THERA, LEP-LHC, QCD Explorer etc) are discussed. The advantages of linac-ring type colliders has been shown comparatively.
Chromomagnetic and chromoelectric dipole interactions of the top quark are studied in a model independent framework. Limits are set on the scale of new physics that might lead to such contributions using available Tevatron data. Prospects at the LHC are reviewed.
The SU(3)$_L\otimesU(1)_N$ electroweak model predicts new Higgs bosons beyond the one of the standard model. In this work we investigate the signature and production of doubly charged Higgs bosons in the $e^-e^+$ International Linear Collider and in the CERN Linear Collider. We compute the branching ratios for the doubly charged gauge bosons of the model.
The energy spectra of the lepton(s) in eebar --> ttbar --> l^{+-}X/ l^+l^- X' at next linear colliders (NLC) are analyzed a model-independent way for arbitrary longitudinal beam polarizations as a general test of possible anomalous top-quark couplings.
We develop a precise power counting rule (a generalization of Weinberg's counting method for the nonlinear sigma model) for the electroweak theories formulated by chiral Lagrangians. Then we estimate the contributions of ``all'' next-to-leading order (NLO) bosonic operators to the amplitudes of the relevant scattering processes which can be measured at high energy colliders, such as the LHC and future Linear Colliders. Based upon these results, we globally classify the sensitivities of testing all NLO bosonic operators for probing the electroweak symmetry breaking mechanism at high energy coll…
Results of complete tree level calculations of the single top production reaction $γe \to ν\bar{t} b$ at the Next Linear Collider, including the contribution of anomalous operators to the Wtb coupling are presented. The sensitivity for probing the structure of the Wtb coupling in a model independent way is analyzed and found to be significantly higher than for comparable measurements at the Tevatron.
The cosmological phase transition with Q-balls production mechanism can explain the baryogenesis and dark matter simultaneously, where constraints on dark matter masses and reverse dilution are significantly relaxed. We study how to probe this scenario by collider signals at QCD next-to-leading order and gravitational wave signals.
Generalized parton distributions (GPDs) enter QCD factorization theorems for hard exclusive reactions. They encode rich information about hadron partonic structure. We explore a possibility to constrain GPDs in experiments at LHC considering two different exclusive processes: the timelike Compton scattering and the photoproduction of heavy vector mesons.
We review our recent global analysis for probing the electroweak symmetry breaking (EWSB) mechanism by the universal effective Lagrangian description. After summarizing and commenting upon the current bounds for the EWSB parameters, we focus on testing them at the forthcoming high energy colliders such as the CERN LHC and the future linear colliders. We develop a precise electroweak power counting method (a la Weinberg) and formulate the longitudinal-Goldstone boson equivalence as a necessary criterion for sensitively probing the EWSB sector. Armed with these, we systematically estimate and cl…
We discuss possibilities to measure the tt-gamma and ttZ couplings at hadron and lepton colliders. We also briefly describe how these measurements can be used to constrain the parameter space of models of new physics, in particular Little Higgs models.
Extending the sensitivity to New Physics beyond the anticipated reach of the LHC is a prime aim of future colliders. This paper summarises the potential of an e+e- linear collider, at and beyond 1 TeV, using a realistic simulation of the detector response and the accelerator induced background. The possible LC energy-luminosity trade-offs offered in probing multi-TeV scales for new phenomena with electro-weak observables are also discussed.
This article presents prospects for Lorentz-violation searches with $t\bar{t}$ at the LHC and future colliders. After a short presentation of the Standard-Model Extension as a Lorentz-symmetry-breaking effective field theory, we will focus on $t\bar{t}$ production. We study the impact of Lorentz violation as a function of center-of-mass energy and evaluate the sensitivity of collider experiments to this signal.
For some choices of soft SUSY--breaking parameters, the LSP is a stable neutralino, the NLSP is a chargino almost degenerate in mass with the LSP (with mass difference $\sim m_π-$few GeV), and all other sparticles are relatively heavy. We discuss the potential of a $\sqrt{s}\sim 600\gev$ $e^+e^-$ collider for studying such models.
Construction of future electron-positron colliders (or dedicated electron linac) and muon colliders (or dedicated muon ring) tangential to Future Circular Collider (FCC) will give opportunity to utilize highest energy proton and nucleus beams for lepton-hadron and photon-hadron collisions. Luminosity values of FCC based ep, \mup, eA, \muA, \gammap and \gammaA colliders are estimated. Multi-TeV center of mass energy ep colliders based on the FCC and linear colliders (LC) are considered in detail. Parameters of upgraded versions of the FCC proton beam are determined to optimize luminosity of ele…
The CP properties of Higgs bosons can be probed through their s-channel resonance productions via photon-photon collisions by use of circularly and/or linearly polarized backscattered laser photons at a TeV-scale linear e^+ e^- collider. Exploiting this powerful tool, we investigate in detail the Higgs sector of the minimal supersymmetric Standard Model with explicit CP violation.
A detailed analysis of ZZ production at the upgraded Fermilab Tevatron and the CERN Large Hadron Collider is presented for general ZZZ and ZZγcouplings. Deviations from the Standard Model gauge theory structure for each of these can be parameterized in terms of two form factors which are severely restricted by unitarity at high energy. Achievable limits on these couplings are shown to be a dramatic improvement over the limits currently obtained by e^+e^- experiments.
We study the effects of heavy Higgs bosons on the top-pair production process at photon linear colliders. The interference patterns between the resonant Higgs-production amplitudes and the continuum QED amplitudes are examined. The patterns tell us not only the CP nature of the Higgs bosons but also the phase of the $γγ$--Higgs vertex which gives new information about the Higgs couplings to new charged particles.
While it is natural for supersymmetric particles to be well within the mass range of the large hadron collider, it is possible that the sparticle masses could be very heavy. Signatures are examined at a very high energy hadron collider and an very high luminosity option for the Large Hadron Collider in such scenarios.
Using the facts that in Gauge-Mediated Supersymmetry Breaking schemes, masses of the right and the left sfermions can differ widely, and the gravitino is the Lightest Supersymmetric Particle, we show that it is possible to obtain unambiguous signatures of such schemes in a high energy $e^+e^-$ collider if one looks at the asymmetries in the cross-sections for certain final states with left-and right-polarized beams.
