Universal Extra Dimension (UED) is a well-motivated and well-studied scenario. One of the main motivations is the presence of a dark matter (DM) candidate namely, the lightest level-1 Kaluza-Klein (KK) particle (LKP), in the particle spectrum of UED. The minimal version of UED (mUED) scenario is highly predictive with only two parameters namely, the radius of compactification and cut-off scale, to determine the phenomenology. Therefore, stringent constraint results from the WMAP/PLANCK measurement of DM relic density (RD) of the universe. The production and decays of level-1 quarks and gluons in UED scenarios give rise to multijet final states at the Large Hadron Collider (LHC) experiment. We study the ATLAS search for multijet plus missing transverse energy signatures at the LHC with 13 TeV center of mass energy and 139 inverse femtobarn integrated luminosity. In view of the fact that the DM RD allowed part of mUED parameter-space has already been ruled out by the ATLAS multijet search, we move on to a less restricted version of UED namely, the non-minimal UED (nmUED), with non-vanishing boundary-localized terms (BLTs). The presence of BLTs significantly alters the dark matter as well as the collider phenomenology of nmUED. We obtain stringent bounds on the BLT parameters from the ATLAS multijet plus missing transverse energy search.
A review of the current experimental results on searches for Higgs bosons in models beyond the Standard Model is presented. Searches from ATLAS, CMS and LHCb use datasets from Run 1 of the LHC, including 7 and 8 TeV proton-proton collisions. Searches from CDF and D0 use the full or partial 1.96 TeV proton-anti-proton collision datasets from the Tevatron.
We consider effective Higgs boson couplings, including both the CP-even and CP-odd couplings, that affect Higgs boson pair production in this study. Through the partial wave analysis, we find that the process $gg\to hh$ is dominated by the $s$-wave component even at a 100~TeV $pp$-collider. Making use of the $s$-wave kinematics, we propose a cut efficiency function to mimic the collider simulation and obtain the potential of measuring Higgs effective couplings at the 14~TeV LHC with an integrated luminosity of $3000~{\rm fb}^{-1}$ and at a 100 TeV $pp$-collider. Analytical expressions of the $…
We study high energy $\small{\rm{pp}}$ and $\small{\rm{\bar {p}p}}$ elastic scattering in the TeV region based on an effective field theory model of the proton. We phenomenologically investigate the main processes underlying elastic scattering and quantitatively describe the measured elastic d$\smallσ$/dt at energies 7.0 TeV (LHC $\small{\rm{pp}}$), 1.96 TeV (Tevatron $\small{\rm{\bar {p}p}}$), and 0.630 TeV (SPS $\small{\rm{\bar {p}p}}$). Finally, we give our prediction for $\small{\rm{pp}}$ elastic d$\smallσ$/dt at 14 TeV that will be measured by the TOTEM Collaboration.
We study the prospects for long-lived charged particle (LLCP) searches at current and future LHC runs and at a 100 TeV pp collider, using Drell-Yan slepton pair production as an example. Because momentum measurements become more challenging for very energetic particles, we carefully treat the expected momentum resolution. At the same time, a novel feature of 100 TeV collisions is the significant energy loss of energetic muons in detectors. We use this to help discriminate between muons and LLCPs. We find that the 14 TeV LHC with an integrated luminosity of 3 ab$^{-1}$ can probe LLCP slepton ma…
Motivated by the null results of LHC searches, which together with the Higgs mass, severely constrain minimal supersymmetric extensions of the standard model, we adopt a model-independent approach to study charged slepton flavor. We examine a number of simplified models, with different subsets of sleptons, electroweak gauginos, and Higgsinos, and derive the allowed slepton flavor dependence in the region probed by current LHC searches, and in the region relevant for the 14 TeV LHC. We then study the impact of the allowed flavor dependence on lepton plus missing energy searches. In some cases, …
Intense and collimated neutrino beams are produced by charm and beauty particle decays from proton-proton collisions at the LHC. A neutrino experiment would be run parasitically without interrupting the LHC physics program during the collider run. We estimate the neutrino fluxes from proton-proton collisions at $\sqrt{s}=14$ TeV of the LHC with the designed luminosity, $10^{34} \lumi$. By mounting about 200 tons of fiducial volume of a neutrino detector at 300 $\m$ away from the interaction point, about 150,000 of charged current neutrino events per year can be observable.
We discuss production of charm and bottom quarks at forward rapidity in pp collisions at the LHC, updating the QCD predictions for the run at \sqrt{S}=13 TeV. We show that, while the absolute rates suffer from large theoretical systematics, dominated by scale uncertainties, the increase relative to the rates precisely measured at 7 TeV can be predicted with an accuracy of a few percent, sufficient to highlight the sensitivity to the gluon distribution function.
We argue that already the first year run at the LHC with 3.5 TeV proton beams will provide a quick and effective way to test the dynamics of the color dipole-gluon interactions and the small x behavior of the gluon density in proton from study of the vector meson photoproduction in ultraperipheral proton-proton collisions.
We investigate the prospects of supersymmetry searches at the LHC with 7 TeV energy. A new set of selection cuts is proposed based on event shapes to control backgrounds. Our preliminary studies show that it is possible to minimize backgrounds to a significantly low level and conservative estimate suggests that the mass reach can be extended to $\sim$ 1.1 TeV for luminosity 1/fb with a reasonable signal-to-background ratio.
The $p_{\perp}$-distributions for the dimuon production at the LHC are calculated in the Randall-Sundrum scenario with a small curvature $κ$. The $pp$ collisions at 7 TeV and 14 TeV are considered. The widths of massive graviton excitations are taken into account. It is found that the LHC discovery limit on 5-dimensional gravity scale $M_5$ is equal to 5.5 TeV for $\sqrt{s} = 7$ TeV and integrated luminositiy 5 fb$^{-1}$. For $\sqrt{s} = 14$ TeV and integrated luminosities 30 fb$^{-1}$ and 100 fb$^{-1}$, the search limits in the dimuon events are 12.0 TeV and 14.6 TeV, respectively. Contrary t…
The CDF PYTHIA 6.2 Tune DW predictions for the behavior of the LHC underlying event (UE) data at 900 GeV and 7 TeV are examined in detail. The behavior of the UE at the LHC is roughly what we expected. The LHC PYTHIA 6.4 Tune Z1 does an excellent job describing the UE data at 900 GeV and 7 TeV. Both Tune DW and Tune Z1 describe fairly well the Drell-Yan UE data at 1.96 TeV and 7 TeV. No model describes all the features of "min-bias" (MB) collisions at 900 GeV and 7 TeV.
We propose TeV-scale Dirac fermions producing Majorana masses of the known neutrinos via tree-level seesaw, different from standard type I and III seesaw. The employed weak five-plet with nonzero hypercharge leads to new seesaw formula m_ν~ v^6/M^5 and to empirical masses m_ν~ 10^{-1} eV for M ~ TeV new states. For a limited range of the parameter space, where M < a few 100 GeV, the proposed mechanism is testable at the LHC via characteristic decays of Dirac type heavy leptons, produced by a Drell-Yan fusion.
We present a renormalizable theory that includes a $W'$ boson of mass in the 1.8-2 TeV range, which may explain the excess events reported by the ATLAS Collaboration in a $WZ$ final state, and by the CMS Collaboration in $e^+\!e^- jj$, $Wh^0$ and $jj$ final states. The $W'$ boson couples to right-handed quarks and leptons, including Dirac neutrinos with TeV-scale masses. This theory predicts a $Z'$ boson of mass in the 3.4-4.5 TeV range. The cross section times branching fractions for the narrow $Z'$ dijet and dilepton peaks at the 13 TeV LHC are 10 fb and 0.6 fb, respectively, for $M_{Z'}= 3.…
We study the precision with which the t-channel single top quark production cross section is expected to be measured in future LHC runs at 14 TeV. The single top final state has a lepton and neutrino from the top quark decay plus two jets, one of which is required to be b-tagged. This measurement is done in the context of the Snowmass 2013 study for the low-luminosity 14 TeV and the high-luminosity 14 TeV LHC as well as for high-luminosity 33 TeV LHC.
If all the supersymmetry particles (sparticles) except a light Higgs boson are too heavy to be directly produced at the Large Hadron Collider (LHC) and Tevatron, a possible way to reveal evidence for supersymmetry is through their virtual effects in other processes. We examine such supersymmetric QCD effects in bottom pair production associated with a light Higgs boson at the LHC and Tevatron. We find that if the relevant sparticles (gluinos and squarks) are well above the TeV scale, too heavy to be directly produced, they can still have sizable virtual effects in this process. For large $\tan…
The measurement of Higgs self-coupling is one of the most crucial physics goals at the future colliders. At the LHC, the di-Higgs production is a main way to measure the Higgs trilinear coupling. As a complementary to the di-Higgs production, $t \bar{t} hh$ process may open a new avenue to measure di-Higgs physics at the LHC and a future 100 TeV $pp$ collider or a high energy $e^+e^-$ collider since the extra $t\bar t$ in the final states may efficiently suppress the backgrounds. However, such a kind of process is also controlled by the top-Higgs coupling. In this work, we investigate the impa…
We present a systematic comparison of jet predictions at the LHC and the Tevatron, with accuracy up to next-to-next-to-leading order (NNLO). The exact computation at NNLO is completed for the gluons-only channel, so we compare the exact predictions for this channel with an approximate prediction based on threshold resummation, in order to determine the regions where this approximation is reliable at NNLO. The kinematic regions used in this study are identical to the experimental setup used by recently published jet data from the ATLAS and CMS experiments at the LHC, and CDF and D0 experiments …
The recent Tevatron measurement of the forward-backward asymmetry of the top quark shows an intriguing discrepancy with Standard Model expectations, particularly at large $\ttbar$ invariant masses. Measurements of this quantity are subtle at the LHC, due to its $pp$ initial state, however, one can define a forward-central-charge asymmetry which captures the physics. We study the capability of the LHC to measure this asymmetry and find that within the SM a measurement at the $5σ$ level is possible with roughly 60 fb$^{-1}$ at $\sqrt{s} = 14$ TeV. If nature realizes a model which enhances the as…
In this work, we derive lower mass bounds on the Z' gauge boson based on the dilepton data from LHC with 13 TeV of center-of-mass energy, and forecast the sensitivity of the High-Luminosity-LHC with $L=3000 fb^{-1}$, the High-Energy LHC with $\sqrt{s}=27$ TeV, and also at the Future Circular Collider with $\sqrt{s}=100$ TeV. We take into account the presence of exotic and invisible decays of the Z' gauge boson to find a more conservative and robust limit, different from previous studies. We investigate the impact of these new decays channels for several benchmark models in the scope of two dif…
The discovery of the Higgs boson at $\sim 125$ GeV indicates that the scale of weak scale supersymmetry is higher than what was perceived in the pre-Higgs boson discovery era and lies in the several TeV region. This makes the discovery of supersymmetry more challenging and argues for hadron colliders beyond LHC at $\sqrt s=14$ TeV. The Future Circular Collider (FCC) study at CERN is considering a 100 TeV collider to be installed in a 100 km tunnel in the Lake Geneva basin. Another 100 km collider being considered in China is the Super proton-proton Collider (SppC). A third possibility recently…
We exploit all LHC available Run 2 data at center-of-mass energies of 8 and 13 TeV for searches for physics beyond the Standard Model. We scrutinize the allowed parameter space of Little Higgs models with the concrete symmetry of T-parity by providing comprehensive analyses of all relevant production channels of heavy vectors, top partners, heavy quarks and heavy leptons and all phenomenologically relevant decay channels. Constraints on the model will be derived from the signatures of jets and missing energy or leptons and missing energy. Besides the symmetric case, we also study the case of T…
If extra dimensions are found in the second run of LHC in the $pp$ collisions at $\sqrt{s}$ = 14 TeV then the string scale can be $\sim$ TeV, and we should produce string balls at LHC. In this paper we study supersymmetry (squark and gluino) production from string balls at LHC in $pp$ collisions at $\sqrt{s}$ = 14 TeV and compare that with the parton fusion results using pQCD. We find significant squark and gluino production from string balls at LHC which is comparable to parton fusion pQCD results. Hence, in the absence of black hole production at LHC, an enhancement in supersymmetry producti…
The LHC is well on track toward the discovery or exclusion of a light Standard Model (SM)-like Higgs boson. Such a Higgs has a very small SM width and can easily have large branching fractions to physics beyond the SM, making Higgs decays an excellent opportunity to observe new physics. Decays into collider-invisible particles are particularly interesting as they are theoretically well motivated and relatively clean experimentally. In this work we estimate the potential of the 7 and 8 TeV LHC to observe an invisible Higgs branching fraction. We analyze three channels that can be used to direct…
In this work we study the collider phenomenology of a compressed supersymmetric model with gluino and the lightest neutralino. All other sparticles are assumed to be heavy. We consider gluino pair production at the 14 TeV LHC and present the mass reach of gluino as a function of mass splitting between gluino and the the lightest neutralino. We find that the gluino mass below 1 TeV can be excluded at 95% CL with integrated luminosity of 100 fb$^{-1}$ for extreme degenerate case where mass separation between gluino and the lightest neutralino is about 20 GeV. On the other hand, the lower bound o…
We present strategies to search for heavy neutral Higgs bosons decaying to top quark pairs, as often occurs at low $\tan β$ in type II two Higgs doublet models such as the Higgs sector of the MSSM. The resonant production channel is unsatisfactory due to interference with the SM background. We instead propose to utilize same-sign dilepton signatures arising from the production of heavy Higgs bosons in association with one or two top quarks and subsequent decay to a top pair. We find that for heavier neutral Higgs bosons the production in association with one top quark provides greater sensitiv…
Multiplicity dependencies of midrapidity transverse momentum distributions of identified charged particles in inelastic proton-proton collisions at center-of-mass energy of 7 TeV at the Large Hadron Collider (LHC), measured by ALICE Collaboration, have been analyzed. The full abstract with important results on the established effective temperature versus energy density dependence, estimated critical energy densities for probable deconfinement phase transition in proton-proton collisions at center-of-mass energy of 7 and 13 TeV and other results is given in the manuscript file.
We present the inclusive Higgs boson cross-section at the LHC with collision energy of 8 TeV. Our predictions are obtained using our publicly available program iHixs which incorporates NNLO QCD corrections and electroweak corrections. We review the convergence of the QCD perturbative expansion at this new energy and examine the impact of finite Higgs width effects. We also study the impact of different parton distribution functions on the cross-section. We present tables with the cross-section values and estimates for their uncertainty due to uncalculated higher orders in the perturbative expa…
We have revisited the prospects of Supersymmetry(SUSY) searches at the LHC with 7 TeV energy along with the prediction of the discovery potential at 8 TeV energy assuming an integrated luminosity 5 $fb ^{-1}$ and 20 $\invfb$ with mSUGRA/CMSSM as a model framework. We discuss further optimization of our selection strategy which is based on the hadronic event shape variables. Evaluating the standard model backgrounds and signal rates in detail we predict the discovery reach in the $m_0 - m_{1/2}$ plane for 7 TeV with 5$\invfb$ luminosity. We also present the discovery reach for 8 TeV energy with…
We describe recent developments of the public computer code HiggsBounds. In particular, these include the incorporation of LHC Higgs search results from Run 2 at a center-of-mass energy of 13 TeV, and an updated and extended framework for the theoretical input that accounts for improved Higgs cross section and branching ratio predictions and new search channels. We furthermore discuss an improved method used in HiggsBounds to approximately reconstruct the exclusion likelihood for LHC searches for non-standard Higgs bosons decaying to $ττ$ final states. We describe in detail the new and updated…
Since the precise study of Higgs gauge couplings is important to test the Standard Model (SM), we calculate the complete next-to-leading order QCD(NLO QCD) correction to the $pp \to HZW^{\pm}$ production in the SM at 14 TeV LHC. Our results show that the NLO QCD correction can enhance the leading-order cross section of $pp \to HZW^{\pm}$ by 45%, when $ m_H $ = 125.3 GeV. We also study the dependence of the LO and NLO corrected cross sections on the renormalization and factorization scale $μ$. Besides, due to the unbalance of parton distribution functions, we investigate the charge asymmetry of…
The ttbar asymmetry measured at the Tevatron continues to disagree with Standard Model predictions at the 3 sigma level. We update the status of the phenomenological light axigluon model in explaining the asymmetry data, taking into account constraints from the charge asymmetry at the LHC and the ttbar cross section at both Tevatron and LHC. We find that an axigluon with a mass between 100 and 400 GeV provides an excellent fit to the data. Recent searches by ATLAS and CMS for pair production of heavy resonances which decay to dijets rule out axigluons with large branching fractions to dijets. …
In the framework Randall-Sundrum-like scenario with the small curvature kappa (RSSC model), p_t-distributions for the dielectron production at the LHC are calculated. For the summary statistics taken at 7 TeV (L = 5 fb-1) and 8 TeV (L = 20 fb-1), the exclusion limit on the 5-dimensional gravity scale M_5 is found to be 6.35 TeV at 95% C.L. For sqrt(s) = 13 TeV and integrated luminosity 30 fb-1, the LHC search limit is estimated to be 8.95 TeV. These limits on M_5 are independent of kappa, provided the relation kappa << M_5 is satisfied.
This contribution contains a brief review of several scenarios for physics beyond the Standard Model at the energy scales accessible to experiments at the Tevatron and the LHC, focusing on their experimental signatures.
The Large Hadron Collider (LHC) recently started operating at 8 TeV. In this note, we update our earlier LHC forward hadronic scattering predictions \cite{physicsreports,update7, blackdisk}, giving new predictions, including errors, for the $pp$ total and inelastic cross sections, the $ρ$-value, the nuclear slope parameter $B$, $dσ_{\rm el}/dt$, and the large gap survival probability at 8 TeV.
The LHC has successfully run for a long period at half energy, 7 TeV. In this note, we update earlier full-energy Large Hadron Collider (LHC) forward hadronic scattering predictions \cite{physicsreports}, giving new predictions, including errors, for the $pp$ total and inelastic cross sections, the $ρ$-value, the nuclear slope parameter $B$, $dσ_{\rm el}/dt$, and the large gap survival probability at the current 7 TeV energy.
We show that the search for supersymmetry at LHC will be very problematic for the particular case of nonuniversal relations among gaugino masses. Namely, if gluino, first chargino and LSP masses are closed to each other it would be very difficult to discover supersymmetry even if sparticle masses are lighter than 1 TeV.
We discuss expectations for the total and inelastic cross-sections at LHC CM energies $\sqrt{s}\ =\ 7\ TeV$ {and $ 14\ TeV$} obtained in an eikonal minijet model augmented by soft gluon $k_t$-resummation, which we describe in some detail. We present a band of predictions which encompass recent LHC data and suggest that the inelastic cross-section described by two channel eikonal models include only uncorrelated processes. We show that this interpretation of the model is supported by the LHC data.
Analysis of the charged multiplicity in proton-proton inelastic interactions at the LHC energies in the setting of Dual Parton Model is presented. Data from the CMS experiment and the data simulated at different energies in various pseudo-rapidity windows using the event generator PYTHIA8are analysed and compared with the calculations from the model. Each inelastic scattering is assumed to follow the Poisson distribution. The theoretical Koba-Nielsen-Olesen (KNO) scaling of the multiplicity distributions is studied and compared with previously published experimental results at $\sqrt{s}$ = 0.9…
We review the modelling of multiple interactions in the event generator Herwig++ and study implications of recent tuning efforts to Tevatron and LHC data. It is often said that measurements of the effective cross section for double-parton scattering, sigma_effective, are in contradiction with models of the final state of multi-parton interactions, but we show that the Herwig++ model is consistent with both and gives stable predictions for underlying event observables at 14 TeV.
In this work we explore the 7 TeV LHC implication on light top squark (stop) and investigate discovery limits at both 8 and 14 TeV LHC using same-sign dilepton signature. We consider a simplified spectrum with gluino pair production followed by heavy gluino decay into on-shell stop and top quark in pair. The light stop is then assumed to uniquely decay into c\tildeχ_1^0, bW^+\tildeχ_1^0 or t\tildeχ_1^0. The same-sign dilepton search at 7 TeV LHC places a lower bound of about 800 GeV on the gluino mass in this scenario. We find that the 8 TeV LHC with 30 fb^{-1} luminosity can reach 960 (900) G…
Models with essential non-perturbative QCD dynamics and describing Tevatron data on high-$p_\perp$ charmonium are extrapolated to give predictions of prompt J/psi production at the LHC. Differences of up to an order of magnitude occurs. An important point is here the treatment of higher order perturbative QCD effects.
In view of the annnouncement that in 2012 the LHC will run at 8 TeV, we study the possibility of detecting signals of alternative mechanisms of ElectroWeak Symmetry Breaking, described phenomenologically by unitarized models, at energies lower than 14 TeV. A complete calculation with six fermions in the final state is performed using the PHANTOM event generator. Our results indicate that at 8 TeV some of the scenarios with TeV scale resonances are likely to be identified while models with no resonances or with very heavy ones will be inaccessible, unless the available luminosity will be much h…
Discussions are underway for a high-energy proton-proton collider. Two preliminary ideas are the $\sqrt{s}=33$ TeV HE-LHC and the $\sqrt{s}=100$ TeV VLHC. With Bayesian statistics, we calculate the probabilities that the LHC, HE-LHC and VLHC discover SUSY in the future, assuming that nature is described by the CMSSM and given the experimental data from the LHC, LUX and Planck. We find that the LHC with $300$/fb at $\sqrt{s}=14$ TeV has a $15$-$75%$ probability of discovering SUSY. Should that run fail to discover SUSY, the probability of discovering SUSY with $3000$/fb is merely $1$-$10%$. Wer…
The process of soft diffractive dissociation in hadronic collisions is discussed in the framework of the Miettinen-Pumplin model. A good description of the data in the ISR-Tevatron energy range is found. Predictions for the total, elastic and single diffractive cross sections for the LHC are also presented. The total cross section is expected to be 15% smaller than that given by Donnachie and Landshoff in the model with soft pomeron. The diffractive cross section remains constant in the Tevatron-LHC energy range.
The Higgs boson $H$ has the largest coupling to the top quark $t$ among the standard model (SM) fermions. This is one of the ideal places to investigate new physics beyond SM. In this work, we study the potential of determining Higgs boson $CP$ properties at the LHC and future 33 TeV and 100 TeV $pp$ colliders by analysing various operators formed from final states variables in $t\bar{t}H$ production. The discrimination power from SM coupling is obtained with Higgs boson reconstructed from $ H\to γγ$ and $ H\to b \bar{b}$. We find that $t\bar{t}b\bar{b}$ process can provide more than 3$σ$ disc…
We present updated predictions for the total cross section for Higgs boson production through gluon fusion at hadron colliders. In addition to renormalization-group improvement at next-to-next-to-next-to-leading logarithmic accuracy, we incorporate the two-loop electroweak corrections, which leads to the most precise predictions at present. Numerical results are given for Higgs masses between 115 GeV and 200 GeV at the Tevatron with \sqrt{s}=1.96 TeV and the LHC with \sqrt{s}=7-14 TeV.
After completion of the LHC8 run in 2012, the plan is to upgrade the LHC for operation close to its design energy sqrt{s}=14 TeV, with a goal of collecting hundreds of fb^{-1} of integrated luminosity. The time is propitious to begin thinking of what is gained by even further LHC upgrades. In this report, we compute an LHC14 reach for SUSY in the mSUGRA/CMSSM model with an anticipated high luminosity upgrade. We find that LHC14 with 300 (3000) fb^{-1} has a reach for SUSY via gluino/squark searches of m(gluino)\sim3.2 TeV (3.6 TeV) for m(squark)\sim m)gluino), and a reach of m(gluino)\sim1.8 T…
We analyze the sensitivity of next-generation tonne-scale neutrinoless double $β$-decay ($0νββ$) experiments and searches for same-sign di-electrons plus jets at the Large Hadron Collider to TeV scale lepton number violating interactions. Taking into account previously unaccounted for physics and detector backgrounds at the LHC, renormalization group evolution, and long-range contributions to $0νββ$ nuclear matrix elements, we find that the reach of tonne-scale $0νββ$ generally exceeds that of the LHC. However, for a range of heavy particle masses near the TeV scale, the high luminosity LHC an…
Stringent experimental constraints have raised the lower limit on the masses of squarks to TeV levels, while compatibility with the mass of the Higgs boson provides an upper limit. This two-sided bound has lead to the emergence of Mini-Split theories where gauginos are not far removed from the electroweak scale while scalars are somewhat heavier. This small hierarchy modifies the spectrum of standard anomaly and gauge mediation, leading to Mini-Split deflected anomaly and gauge mediation models. In this paper, we study LHC constraints on these models and their prospects at LHC 14 and a 100 TeV…
We consider a scenario in which TeV-scale particles belonging to weak-isospin multiplets higher than triplets lead to novel seesaw mechanisms different from conventional type I, II and III seesaw models. Besides an appealing testability of these mechanisms at the LHC, the model with Majorana quintuplets with imposed discrete symmetry may provide viable dark matter candidate.
If a heavy Dirac monopole exists, the light to light scattering below the monopole production threshold is enhanced due to the strong coupling of monopoles to photons. This effect could be observable in the collision of virtual photons at proton colliders. At the Tevatron it will be seen as pair production of photons with energies 200--400 GeV and roughly compensated transverse momenta 100--400 GeV/c. This effect could be seen at monopole masses about 1--2.5 TeV at the upgraded Tevatron and 7.4--19 TeV at LHC depending on monopole spin.
We study extensions of the Minimal Supersymmetric Standard Model (MSSM) with new degrees of freedom that couple sizably to the MSSM Higgs sector and lie in the TeV range. After integrating out the physics at the TeV scale, the resulting Higgs spectrum can significantly differ from typical supersymmetric scenarios, thereby providing a window Beyond the MSSM (BMSSM). Taking into account current LEP and Tevatron constraints, we perform an in-depth analysis of the Higgs collider phenomenology and explore distinctive characteristics of our scenario with respect to both the Standard Model and the MS…
We analyse the multiplicity distributions of charged particles at Tevatron (p\bar p) and LHC (pp) energies in the framework of the independent pair parton interactions (IPPI) model. It is shown that the number of soft pair parton interactions (and therefore the density of the partonic medium) is large and increases with energy. The mean multiplicity at each parton interaction grows also with energy. This growth depends on the width of the rapidity window. The similar conclusions are obtained in the multiladder exchange model (QGSM).
We show that the LHC will be able to differentiate between a four-dimensional model with quantum gravity at ~1 TeV where the (massless) graviton becomes strongly coupled to standard model particles at 1 TeV and brane world type models with a large extra-dimensional volume and massive Kaluza-Klein gravitons. We estimate that the 14 TeV LHC could put a limit of the order of ~5 TeV on the four dimensional Planck mass in a model independent way.
The aim of this work is to explore the possibility to discover a fermionic field with mass dimension one, the Elko field, in the 14 TeV Large Hadron Collider (LHC), in processes with missing energy and one jet. We explore the possibility of a triple coupling with the Higgs field, generating also a contribution to the Elko mass term, and suggest some possibilities for future studies in this field.
We investigate the implications for supersymmetry from an assumed absence of any signal in the first period of LHC data taking at 7 TeV center-of-mass energy and with 1 to 7 fb^(-1) of integrated luminosity. We consider the zero-lepton plus four jets and missing transverse energy signature, and perform a combined fit of low-energy measurements, the dark matter relic density constraint and potential LHC exclusions within a minimal supergravity model. A non-observation of supersymmetry in the first period of LHC data taking would still allow for an acceptable description of low-energy data and t…
We explore the possibility of observing elliptic flow in low multiplicity events in central pp collisions at LHC energy, $\sqrt{s}$=14 TeV. It is assumed that the initial interactions produces a number of hot spots. Hydrodynamical evolution of two or more hot spots can generate sufficiently large elliptic flow to be accessible experimentally in 4-th order cumulant analysis.
Heavy quarkonium production in the framework of the non-relativistic quantum chromodynamics and leading order of the parton Reggeization approach at the Tevatron and LHC is discussed. In this note, we compare our predictions for the bottomonium production at the LHC due to the color-singlet approximation of the non-relativistic quantum chromodynamics with CMS and LHCb data. It is found, that in the production of Upsilon(1S) states, the color-singlet mechanism is dominating, whereas to describe the data for the inclusive Upsilon(2S) and Upsilon(3S) production, the color- octet contributions sho…
