In the framework of the topcolor-assisted technicolor $(TC2)$ model, we study production of the neutral top-pion $π_{t}^{0}$ in association with a high-$p_{T}$ jet at the $LHC$, which proceeds via the partonic processes $gg\longrightarrow π_{t}^{0}g$, $gq\longrightarrow π_{t}^{0}q$, $q\bar{q}\longrightarrow π_{t}^{0}g$, $gb(\bar{b})\longrightarrow π_{t}^{0}b(\bar{b})$, and $b\bar{b}\longrightarrow π_{t}^{0}g$. We find that it is very challenging to detect the neutral top-pion $π_{t}^{0}$ via the process $pp\longrightarrow π_{t}^{0}+jet+X\to t\bar{t}+jet+X$, while the possible signatures of $π_{t}^{0}$ might be detected via the process $pp\longrightarrow π_{t}^{0}+jet+X\to(\bar{t}c+t\bar{c})+jet+X$ at the $LHC$.
Charmonium production in association with a forward or backward pion in nucleon-antinucleon annihilation is one of the most promising reaction to access nucleon-to-pion transition distribution amplitudes (TDAs) at PANDA. We briefly review the description of this reaction in terms of πN TDAs within the collinear factorization approach and present the first results of dedicated feasibility studies for the PANDA experimental setup.
We calculate techni-pion masses of the walking technicolor (WTC), by explicitly evaluating nontrivial contributions from various possible chiral breaking sources in a concrete WTC setting of the one-family model. Our explicit computation of the mass and the coupling in this concrete model setting reveals that the techni-pions are on the order of several hundred GeV in the region to be discovered at LHC.
We review the potential of the LHC to detect a very light CP-odd Higgs boson of the NMSSM, $a_1$, through its direct production in association with a bottom-quark pair at large tan$β$. We also review the LHC discovery potential of the two lightest CP-even Higgs states, decaying into two lighter Higgs states or into the lightest CP-odd Higgs state and the $Z$ gauge boson.
To settle the question whether the growth with energy is universal for different hadronic total cross-sections, we present results from theoretical models for pion-proton, proton-proton and proton-antiproton total cross-sections. We show that present and planned experiments at LHC can differentiate between different models, all of which are consistent with presently available (lower energy) data. This study is also relevant for the analysis of those very high energy cosmic ray data which require reliable pion-proton total cross-sections as seeds. A preliminary study of the total pion-pion cros…
The production of charm quark jets in association with electroweak gauge bosons at the LHC can be used as a tool to constrain quark parton distribution functions. Motivated by recent measurements at the LHC, we calculate cross sections for W/Z +c, comparing these to W/Z+jet, for various PDF sets. The cross-section differences can be understood in terms of the different underlying PDFs, with the strange quark distribution being particularly important for W +c production. We discuss appropriately defined ratios and comment on how the measurements at the LHC can be used to extract information on …
The dominant contribution to the Higgs production in association with bottom quark pair at the LHC is gluon-gluon fusion parton subprocess. We present a complete calculation of the next-to-leading order (NLO) electroweak (EW) corrections to this channel. The other small contributions with quarks in the initial state are calculated at tree level. We find that the NLO EW corrections can suppress the leading order (LO) contributions significantly.
The production of charm quark jets in association with electroweak gauge bosons at the LHC can be used as a tool to constrain quark parton distribution functions (PDFs). Motivated by recent measurements at the Tevatron and LHC, we calculate cross sections for $W/Z+c$, comparing these to $W/Z+\textrm{jet}$, for various PDF sets. The cross-section differences can be understood in terms of the different underlying PDFs, with the strange quark distribution being particularly important for $W+c$ production. We suggest measurements of appropriately defined ratios and comment on how these measurement…
The top-pions($π_{t}^{0,\pm}$) predicted by extra dimensional descriptions of the topcolor scenario have similar feature with those in four dimensional topcolor scenario, which have large Yukawa couplings to the third generation quarks. In the context of the higgsless--top-Higgs(HTH) model, we discuss the production of these new particles at the CERN Large Hadron Collider(LHC) via various suitable mechanisms (gluon-gluon fusion, bottom-bottom fusion, gluon-bottom fusion, and the usual Drell-Yan processes) and estimate their production rates. We find that, as long as the top-pions are not too h…
The single vector-like top partner hadroproduction in association with top quark in the five and the six-flavour schemes at the LHC is investigated. The inclusive cross section and the differential distributions are evaluated for many benchmark scenarios at leading and next-to-leading orders, both for fixed-order and fixed-order matched to parton shower. The associated Higgs production with a top quark pair, where the final state arises from the decay of the vector-like top partner into a Higgs boson and a top quark, is examined.
Higgs production in association with three jets via gluon fusion (GF) is an important channel for the measurement of the CP-properties of the Higgs particle at the LHC. In this letter, we go beyond the heavy top effective theory approximation and include at LO the full mass dependence of the top- and bottom-quark contributions. We consider the dominant sub-channel gg -> H ggg which involves the manipulation of massive rank-5 hexagon integrals. Furthermore, we present results for several differential distributions and show deviations from the effective theory as large as 100% at high pT for lig…
Considering the experimental constraints given by CMS collaboration at $\sqrt{s} = 8$ TeV on the strength of top quark flavour-changing neutral-current (FCNC) couplings $tqγ$ and $tqg$, we investigate the production of top quark in association with a photon and carry out a full simulation for the signals $\ellνbγ$ and $jjbγ$ at 14 TeV LHC. In our numerical analysis, the contributions of single top production with a photon radiation off the top decay products are also included. The discovery potential for anomalous couplings $tqγ$ and $tqg$ with an integrated luminosity of 100 fb$^{-1}$ are exa…
The direct observation of the Yukawa interaction related to Standard Model Higgs and the bottom quark is obtained from the $h\to b\bar{b}$ process recently. The b-tagging becomes an important tool to search for new heavy resonance production at LHC. We use the b-tagging method to investigate the neutral Higgs production in association with a bottom quark pair, and perform the detector simulation for the signal process with the Higgs decaying into $b\bar{b}$ or $τ^+τ^-$ together with the dominant backgrounds. Our results show that $b\bar{b}b\bar{b}$ and $b\bar{b}τ^+τ^-$ processes will play an i…
We study the jets plus missing energy signature at the LHC in a scenario where the gravitino is very light and the gluino is the next-to-lightest supersymmetric particle and promptly decays into a gluon and a gravitino. We consider both associated gravitino production with a gluino and gluino pair production. By merging matrix elements with parton showers, we generate inclusive signal and background samples and show how information on the gluino and gravitino masses can be obtained by simple final state observables.
The topcolor-assisted technicolor (TC2) model predicts the existence of the charged top-pions ($π_t^\pm$), whose large couplings with the third generation fermions will induce the charged top-pion production associated with the bottom and anti-bottom quark pair at the CERN Large Hadron Collider (LHC) through the parton processes $c\bar b \to π_t^+ b \bar b$ and $u\bar d(c\bar s) \to π_t^+ b \bar b$. In this paper we examine these productions and find that, due to the small Standard Model backgrounds, their production rates can exceed the $3σ$ sensitivity of the LHC in a large part of parameter…
We report on the calculation of the next-to-leading order QCD corrections to the production of top--antitop-quark pairs in association with a hard jet at the Tevatron and at the LHC. Results for integrated and differential cross sections are presented. We find a significant reduction of the scale dependence. In most cases the corrections are below 20% indicating that the perturbative expansion is well under control. Moreover, the forward--backward charge asymmetry of the top-quark, which is analyzed at the Tevatron, is studied at next-to-leading order. We find large corrections suggesting that…
In this talk, we present NLO pQCD predictions for inclusive pion and direct photon nuclear modifications in p+Pb collisions at mid- and forward rapidities at the LHC. In addition to the minimum bias predictions, we also address the centrality dependence with spatially dependent nuclear PDFs. To understand which regions of the nuclear momentum fraction $x_2$ these observables predominantly probe, we present also the underlying $x_2$ distributions at different rapidities. We are led to conclude that the isolated photons at forward rapidities are more sensitive to the small-$x_2$ dynamics than th…
We study the photoproduction of the charged top-pion predicted by the top triangle moose ($TTM$) model (a deconstructed version of the topcolor-assisted technicolor $TC2$ model) via the processes $pp\rightarrow p γp \rightarrow π^\pm_t t +X$ at the 14 $TeV$ Large Hadron Collider ($LHC$) including next-to-leading order ($NLO$) $QCD$ corrections. Our results show that the production cross sections and distributions are sensitive to the free parameters $\sinω$ and $M_{π_t}$. Typical $QCD$ correction value is $7\% \sim 11\%$ and does not depend much on $\sinω$ as well as the forward detector accep…
In the context of the little Higgs models, we discuss single production of the new charged gauge bosons in association with top quark at the $CERN$ Large Hadron Collider$(LHC)$. We find that the new charged gauge bosons $W_{H}^{-}$ and $X^{-}$, which are predicted by the littlest Higgs model and the SU(3) simple model, respectively, can be abundantly produced at the $LHC$. However, since the main backgrounds coming from the processes $pp\to t\bar{t}+X$ and $pp\to tW^{-}+X$ are very large, the values of the ratios $N_{W}$ and $N_{X}$ are very small in most of the parameter space. It is only pos…
We calculate the next-to-leading order (NLO) QCD corrections to the $J/ψ+W$ production at the LHC, and provide the theoretical distribution of the $J/ψ$ transverse momentum. Our results show that the differential cross section $\frac{dσ}{dp_T^{J/ψ}}$ at the LO is significantly enhanced by the NLO QCD corrections. We believe that the comparison between the theoretical predictions for the $J/ψ+W$ production and the experimental data at the LHC can provide a verification for the colour-octet mechanism of non-relativistic QCD in the description of the processes involving heavy quarkonium.
We evaluate differential distributions for the four-body $p p \to p p π^+ π^-$ reaction which constitutes a irreducible background to three-body processes $p p \to p p M$, where $M$ are a broad resonances in the $π^+ π^-$ channel, e.g. $M=σ, ρ^{0}, f_{0}(980), f_{2}(1275), f_{0}(1500)$. We include both double-diffractive contribution (both pomeron and reggeon exchanges) as well as the pion-pion rescattering contribution. The first process dominates at higher energies and small pion-pion invariant masses while the second becomes important at lower energies and higher pion-pion invariant masses.…
We present a detailed study of Higgs boson production in association with a single top quark at the LHC, at next-to-leading order accuracy in QCD. We consider total and differential cross sections, at the parton level as well as by matching short distance events to parton showers, for both t-channel and s-channel production. We provide predictions relevant for the LHC at 13 TeV together with a thorough evaluation of the residual uncertainties coming from scale variation, parton distributions, strong coupling constant and heavy quark masses. In addition, for t-channel production, we compare res…
The rates for diffractive quarkonium plus prompt-photon associated production at the LHC are estimated. The theoretical framework considered in the J/Psi (or Upsilon) production associated with a direct photon at the hadron collider is the non-relativistic QCD (NRQCD) factorization formalism. The corresponding single diffractive cross section is computed based on the hard diffractive scattering factorization supplemented by absorptive corrections. Such processes are sensitive to the gluon content of the Pomeron at small Bjorken-x and they may also be a good place to test the different availabl…
We study neutral and charged Higgs boson production in association with stop and sbottom squarks at the Large Hadron Collider (LHC), within the so-called M-SUGRA scenario, i.e., the Supergravity (SUGRA) inspired Minimal Supersymmetric Standard Model (MSSM). For low values of \tanβonly the cases \tilde{t}_1\tilde{t}_1^* H, \tilde{t}_1\tilde{t}_1^* h and \tilde{t}_1\tilde{t}_2^* h give detectable rates while for \tanβgreater than 30 a variety of signals involving all Higgs bosons can be accessed, at high collider luminosity. The dependence of these reactions on the M-SUGRA parameters might furth…
We present results for the production of a Z boson in association with single top at next-to-leading order (NLO), including the decay of the top quark and the Z boson. This electroweak process gives rise to the trilepton signature l+l-l'+- + jets + missing energy. We present results for this signature and show that the rate is competitive with the contribution of the mixed strong and electroweak production process, ttZ. As such it should be observable in the full data sample from LHC running at $\sqrt{s}=8$ TeV. The single top + Z process is a hitherto unconsidered irreducible background in se…
We study the possibility to observe sterile neutrinos with masses in the range between 5 GeV and 20 GeV at the LHC, using the exclusive semileptonic modes involving pions, namely W to lepton + N to n pions + lepton+lepton (n = 1, 2, 3). The two pion and three pion modes require extrapolations of form factors to large time-like $q^2$, which we do using vector dominance models as well as light front holographic QCD, with remarkable agreement. This mass region is difficult to explore with inclusive dilepton+dijet modes or trilepton modes and impossible to explore in rare meson decays. While parti…
Possibility of observing associated production of charged Higgs and W boson in the framework of MSSM at LHC is studied. Both leptonic and hadronic decays of W boson are studied while the charged Higgs boson is considered to decay to a $τ$ lepton and a neutrino. Therefore two search categories are defined based on the leptonic and hadronic final states, i.e. $\ell τ+E^{miss}_{T}$ and $jj τ+E^{miss}_{T}$ where $\ell=e$ or $μ$ and $j$ is a light jet from $W$ decay. The discovery chance of the two categories is evaluated at an integrated luminosity of 300 \invfb at LHC. It is shown that both lepto…
Higgs boson production in association with a hard central photon and two forward tagging jets is expected to provide valuable information on Higgs boson couplings in a range where it is difficult to disentangle weak-boson fusion processes from large QCD backgrounds. We present next-to-leading order QCD corrections to Higgs production in association with a photon via weak-boson fusion at a hadron collider in the form of a flexible parton-level Monte Carlo program. The QCD corrections to integrated cross sections are found to be small for experimentally relevant selection cuts, while the shape o…
We discuss charm quark/antiquark and charmed meson production in association with one extra jet (gluon, quark, antiquark) at the LHC. The calculations are performed both in collinear and $k_T$-factorization approaches. Different unintegrated gluon distribution functions are used in the $k_T$-factorization approach. Several predictions for the LHC are presented. We show distributions in rapidity and transverse momenta of $c$/$\bar c$ (or charmed mesons) and the associated jet as well as some two-dimensional observables. Interesting correlation effects are predicted, \textit{e.g.} in azimuthal a…
The precise knowledge of photon pair production rates at the LHC is crucial to estimate the sensitivity to a Higgs boson in the intermediate mass range. This background consists not only of prompt photons but also of fake photons stemming from pion decay. We present next to leading order predictions for the invariant mass distributions of pion photon and pion pairs.
We compute the hadronic production of top-antitop pairs in association with a Higgs boson at next-to-leading-order QCD, including the decay of the top and antitop quark into bottom quarks and leptons. Our computation is based on full leading and next-to-leading-order matrix elements for $e^+ ν_e μ^-\barν_μb \bar{b} H(j)$ and includes all non-resonant contributions, off-shell effects and interferences. Numerical results for the integrated cross section and several differential distributions are given for the LHC operating at 13 TeV using a fixed and a dynamical factorization and renormalization…
In order to characterize the transverse momentum spectra of positive pions measured in the ALICE experiment, two thermal approaches are utilized; one is based on degeneracy of non-perfect Bose-Einstein gas and the other imposes an {\it ad-hoc} finite pion-chemical potential. The inclusion of missing haron states and the out-of-chemical equilibrium greatly contribute to the excellent characterization of pion production. The excellent reproduction of the experimental data can be understood as a manifestation of not-yet-regarded anomalous pion-production, which likely contribute to the long-stand…
In the topcolor-assistant technicolor (TC2) model, the typical physical particles, top-pions and top-Higgs, are predicted and the existence of these particles could be regarded as the robust evidence of the model. These particles are accessible at the Tevatron and LHC, and furthermore the flavor-changing(FC) feature of the TC2 model can provide us a unique chance to probe them. In this paper, we study some interesting FC production processes of top-pions and top-Higgs at the Tevatron and LHC, i.e., $cΠ_{t}^{-}$ and $cΠ_{t}^{0}(h_{t}^{0})$ productions. We find that the light charged top-pions a…
We present an implementation of the full electroweak $H+2~\text{jets}$ production process at hadron colliders in the framework of the $\tt{POWHEG~BOX}$, a public tool for the matching of fixed-order perturbative calculations with parton shower generators. Our implementation allows for the simultaneous description of vector-boson fusion and Higgsstrahlung contributions. NLO-QCD and electroweak corrections are taken into account and matched to QCD and QED showers, respectively. The size of the fixed-order QCD and electroweak corrections is found to be moderate, but dependent on the considered se…
The production of the lightest Higgs boson, $h^0$, in association with the lightest stop, $\tilde{t}_{1}$, in the Minimal Supersymmetric Standard Model, is an interesting channel, as its cross section can be higher than Higgs production in association with top quarks. Furthermore, the $\tilde{t}_{1}\tilde{t}^{*}_{1}h^{0}$ production rate is highly dependent on various Supersymmetric parameters. The mass, mixings, couplings and production cross sections relevant to the $\tilde{t}_{1}\tilde{t}^{*}_{1}h^{0}$ channel have been studied in the past. Here, we complement these analyses by performing a…
We propose a measurement of leading neutrons spectra at LHC in order to extract inclusive $π^+ p$ and $π^+π^+$ cross-sections with high $p_T$ jets production. The cross-sections for these processes are simulated with the use of parton distributions in hadrons. In this work we estimate the possibility to extract parton distributions in the pion from the data on these cross-sections and also search for signatures of fundamental differences in the pion and proton structure.
Dilepton production in proton-proton collision through $γγ$-fusion with one proton scattered elastically while the second produces a hadron jet is considered. Semi-analytical formulas describing the cross section of a muon pair production are presented.
We investigate the possibility of detectable 2-Higgs Doublet Model (2HDM) type-II cross-sections at the High-Luminosity phase of the Large Hadron Collider (HL-LHC) for the production of the Standard Model (SM)-like Higgs boson ($h$) in association with a single top (anti)quark over the parameter space region corresponding to the so-called `wrong-sign solution' of the bottom (anti)quark Yukawa coupling. We isolate the latter by using the toolbox Magellan, which performs Markov Chain Monte Carlo (MCMC) scans in the presence of all current theoretical and experimental constraints, which relevance…
We study the processes `gluon gluon -> squark antisquark CP-odd Higgs' within the theoretical framework of the Supergravity (SUGRA) inspired Minimal Supersymmetric Standard Model (MSSM) at the leading order (LO) in perturbative Quantum Chromo-Dynamics (QCD). Other than constituting a novel production mechanism of the neutral, CP-odd Higgs particle, they also allow one to relate the size of the corresponding production rates to the ratio of the vacuum expectation values of the two Higgs fields tan(beta), to the trilinear couplings A_0 and to the sign of the Higgsino mass term sign(mu). This int…
We discuss the production of photon-pion and pion pairs with a large invariant mass at collider energies. We present a study based on a perturbative QCD calculation at full next-to-leading order accuracy, implemented in the computer programme DIPHOX. We give estimations for various observables, which concern the reducible background to the Higgs boson search in the channel H --> gamma gamma, in the mass range 80-140 GeV at the LHC. We critically discuss the reliability of these estimates due to our imperfect knowledge of fragmentation functions at high z and a subtle interplay between higher o…
We calculate the total cross section for single charged slepton production in association with a top quark at hadron colliders in the baryon triality (B$_3$) supersymmetric model. We compute event rates for the Tevatron and LHC. We study the signatures for different supersymmetric scenarios including neutralino and stau LSPs. We perform a detailed analysis with basic cuts for the B$_3$ operator $\lam^\prime_{231}$ using Monte Carlo simulations to show that the signal can be distinguished from the background at the LHC. In particular we employ the resulting lepton charge asymmetry.
The intriguing possibility of Bose-Einstein condensation of pions at the LHC is examined with the use of higher order moments of the multiplicity distribution. The scaled variance, skewness and kurtosis are calculated for the pion system. The obtained results show that the normalized kurtosis has a significant increase for the case of the pion condensation.
We investigate the associated production of a neutral physical pion with top quarks in the context of topcolor assisted technicolor. We find that single-top associated production does not yield viable rates at either the Tevatron or LHC. tt-associated production at the Tevatron is suppressed relative to Standard Model ttH, but at the LHC is strongly enhanced and would allow for easy observation of the main decay channels to bottom quarks, and possible observation of the decay to gluons.
If Micro Black Holes (MBHs) can be produced at the LHC, they will decay very fast. We study hypothetical MBHs that do not decay; in particular, QCD effects on accretion by MBHs that are produced at rest. We explain why accretion of a nucleon by such MBHs is associated with pion emission. This pion emission results in a kick to the MBHs, such that their velocities are large enough to escape the Earth. Our study provides an extra assurance that MBHs which might be produced at the LHC are not dangerous.
The first computation of Higgs production in association with three jets at NLO in QCD has recently been performed using the effective theory, where the top quark is treated as an infinitely heavy particle and integrated out. This approach is restricted to the regions in phase space where the typical scales are not larger than the top quark mass. Here we investigate this statement at a quantitative level by calculating the leading-order contributions to the production of a Standard Model Higgs boson in association with up to three jets taking full top-quark and bottom-quark mass dependence int…
In this work, we investigate the associated production of prompt heavy quarkonium with a massive (anti)bottom quark to leading order in the NRQCD factorization formalism at the LHC. We present numerical results for the processes involving $J/ψ,χ_{cJ},Υ$ and $χ_{bJ}$. From our work, we find that the production rates of these processes are quite large, and these processes have the potential to be detected at the LHC. When $p_T$ is smaller than about 10 GeV, the $c\bar{c} [ ^1S_0^{(8)} ]$ state give the main contribution to the $p_T$ distribution of prompt $J/ψ$ with a (anti)bottom quark producti…
We study single top quark production in association with a $WZ$ pair at the LHC in the context of the Standard Model (SM) and the Standard Model Effective Field Theory (SMEFT). A significant advantage of $tWZ$ compared to other EW top production processes is its sensitivity to unitarity-violating behaviour induced in its $2\to2$ sub-amplitudes through modified EW interactions. At NLO in QCD, $tWZ$ interferes with $t\bar{t}Z$ and $t\bar{t}$ and a method to meaningfully separate it from these overlapping processes needs to be employed. In order to define $tWZ$ production for total rates and diff…
We look at the new two-particle correlation function that can provide the space-time information about the source of two charged pions. This function clearly reflects the chaotic and incoherent nature of the particle emission source disturbed by external forces (fields). We argue that such an investiga- tion could probe the size and the temperature of the expanded source where two pions are emitted in thermal environment.
The decay of fireballs containing the disoriented chiral condensate (DCC) in A+A collisions has been analyzed. We found that the high phase-space density and probably the large final fireball volume are the favorable factors to extract a DCC signal from the thermal background. Both of these factors are expected to take place at RHIC and LHC energies. A coherent pion component then can be observed in pion spectra, in Bose-Einstein correlations and in distribution of the ratio of neutral to total pions.
We evaluate the cross section for anti-p p -> l+ l- pi0 in the forward direction and for large lepton pair invariant mass. In this kinematical region, the leading-twist amplitude factorises into a short-distance matrix element, long-distance dominated antiproton Distribution Amplitudes and proton to pion Transition Distribution Amplitudes (TDA). Using a modelling inspired from the chiral limit for these TDAs, we obtain a first estimate of this cross section, thus demonstrating that this process can be measured at GSI-FAIR.
We study the photoproduction of exclusive $2π^+2π^-$ mesons in ultra-peripheral heavy-ion collisions at RHIC and LHC energies. Predictions in photon-nucleus interactions are calculated for various resonances at central and forward rapidities. The recent H1 preliminary data are utilized to improve the description of the poorly known $γp \to 4π^\pm p$ process. We present the comparisons of our results to the available STAR data at RHIC, and made predictions for LHC energies.
The centrality dependencies of the inclusive neutral pion and prompt photon nuclear modification factors for p+Pb collisions at the LHC are studied using a spatially dependent set of nuclear PDFs, EPS09s. The calculations are performed at mid- and forward rapidities searching for an observable which would optimally probe the spatial dependence of the nuclear PDFs. In addition, we discuss to which $x$ values of the nucleus the different observables are sensitive.
We discuss the processes where a KK-graviton ($G$) of the extra-dimensional models is produced in association with a color singlet boson via gluon fusion at the LHC. In particular, we consider the processes $gg \to h G$, $γG$, $Z G$. These processes occur at one-loop through box and triangle diagrams. The cross-section for the process $gg \to γG$ vanishes at the one-loop level. It can be understood by introducing the charge conjugation transformations of the KK-graviton. The processes $gg \to h G$, $Z G$ can be observed at the LHC if the KK-graviton and the Higgs boson exist with appropriate p…
Large Hadron Collider (LHC) had produced a vast amount of high precision data for high energy heavy ion collision. We attempt here to study (i) transverse momenta spectra, (ii) $K/π$, $p/π$ ratio behaviours, (iii)rapidity distribution, and (iv) the nuclear modification factors of the pion, kaon and antiproton produced in $p+p$ and $Pb+Pb$ collisions at energy $\sqrt{s_{NN}}$ = 2.76 TeV, on the basis of Sequential Chain Model (SCM). Comparisons of the model-based results with the measured data on these observables are generally found to be modestly satisfactory.
The sensitivity of the LHC experiments to the associated production of dark matter with a single top is studied in the framework of an extension of the standard model featuring two Higgs doublets and an additional pseudoscalar mediator. It is found that the experimental sensitivity is dominated by the on-shell production of a charged Higgs boson, when this assumes a mass below 1 TeV. Dedicated selections considering one and two lepton final states are developed to assess the coverage in parameter space for this signature at a centre-of-mass energy of 14 TeV assuming an integrated luminosity of…
We compute the two-loop QCD helicity amplitudes for the production of a Higgs boson in association with a bottom-quark pair at a hadron collider. We take the approximations of leading colour and work in the five flavour scheme, where the bottom quarks are massless while the Yukawa coupling is non-zero. We extract analytic expressions from multiple numerical evaluations over finite fields and present the results in terms of an independent set of special functions that can be reliably evaluated over the full phase space.
The expected rate for Multiple Parton Interactions (MPI) at the LHC is large. This requires an estimate of their impact on all measurement foreseen at the LHC. Conversely it provides new means of studying MPI at the LHC. In this paper we examine the role of MPI at the LHC, with the design energy of 14 TeV, in - Z production in association with four jets, - W\pm W\pm in association with zero or two jets. -W+ W- in association with two jets. In all cases the vector bosons are assumed to decay leptonically. The MPI contribution to Z+4j is dominated by events with two jets with balancing transvers…
The $W$-pair production in association with a massive (anti)bottom jet is not only an important background to a number of interesting processes, such as the single top production associated with a W boson, but also a potential background to new physics searches. We present the calculations of the total and differential cross sections for the $W^+W^-+ b(\bar{b})$ jet productions at the LHC up to the QCD next-to-leading order (NLO). Our results by adopting the QCD NLO contribution collection scheme-I show that the K factors can be 1.66 and 1.21 with the inclusive and exclusive two-jet event sele…
