Estia J. Eichten, Kenneth Lane, Adam Martin
We propose that the 3.2 sigma excess at ~150 GeV in the dijet mass spectrum of W + jets reported by CDF is the technipion $π_T$ of low-scale technicolor. Its relatively large cross section is due to production of a narrow $Wjj$ resonance, the technirho, which decays to W + $π_T$. We discuss ways to enhance and strengthen the technicolor hypothesis and suggest companion searches at the Tevatron and LHC.
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Under the assumption that the dijet excess seen by the CDF Collaboration near 150 Gev in Wjj production is due to the lightest technipion of the low-scale technicolor process $ρ_T \rightarrow W π_T$, we study its observability in LHC detectors with 1-5 fb^{-1} of data. We find that cuts similar to those employed by CDF are unlikely to confirm its signal. We propose cuts tailored to the LSTC hypothesis and its backgrounds at the LHC that can reveal $π_T \rightarrow jj$. We also stress the importance at the LHC of the isospin-related channel $ρ^{\pm}_T \rightarrow Zπ^{\pm}_T \rightarrow \ell\ell…
We study the constraints on models of topcolor-assisted technicolor arising from measurements of high-$E_T$ jets and high-mass lepton pairs at the Tevatron collider. Existing data can eliminate models that have appeared in the literature.
Under the assumption that the dijet excess seen by the CDF Collaboration near 150 Gev in Wjj production is due to the lightest technipion of the low-scale technicolor process $ρ_T \rightarrow W π_T$, we study its observability in LHC detectors with 1--20 inverse femtobarns of data. We describe interesting new kinematic tests that can provide independent confirmation of this LSTC hypothesis. We find that cuts similar to those employed by CDF, and recently by ATLAS, cannot confirm the dijet signal. We propose cuts tailored to the LSTC hypothesis and its backgrounds at the LHC that may reveal $ρ_…
CDF and D0 each have more than 1 inverse femtobarn of data on tape, and their stores are increasing. This should be sufficient to carry out significant searches for low-scale technicolor in rho_T --> W pi_T and omega_T, rho_T --> gamma pi_T, processes whose cross sections may be as large as several picobarns. In this note we motivate and describe the Technicolor Straw Man framework for these processes and we urge that they be sought soon in the Run 2 data. (This paper is a contribution to the TeV4LHC Landscapes project.)
The Tevatron experiments CDF and DO are close to making definitive statements about the technicolor discovery mode rho_T -> W pi_T for M(rho_T) <~ 230 GeV and M(pi_T) <~ 125 GeV. We propose new incisive tests for this mode and searches for others that may be feasible at the Tevatron and certainly are at the LHC. The other searches include two long discussed, namely, omega_T -> gamma pi_T and l+l-, and a new one -- for the I^G J^{PC} = 1^- 1^{++} partner, a_T, of the rho_T. Adopting the argument that the technicolor contribution to S is reduced if M(a_T) is near M(rho_T), we enumerate important…
Under the assumption that the dijet excess seen by the CDF Collaboration near 150 Gev in Wjj production is due to the lightest technipion of the low-scale technicolor process $ρ_T \rightarrow W π_T$, we study its observability in LHC detectors for 8 TeV collisions and 20 inverse femtobarns of integrated luminosity. We describe interesting new kinematic tests that can provide independent confirmation of this LSTC hypothesis. We show that cuts similar to those employed by CDF, and recently by ATLAS, cannot confirm the dijet signal. We propose cuts tailored to the LSTC hypothesis and its backgrou…
We briefly review the basic structure of modern--day technicolor theories. We then discuss the signatures for technicolor as they were in its early days, the searches that have been recently performed at the Tevatron and LEP colliders, and the prospects for testing technicolor in Tevatron Run II and at the LHC.
In multiscale models of walking technicolor, relatively light color-singlet technipions are produced in $q \ol q$ annihilation in association with longitudinal $W$ and $Z$ bosons and with each other. The technipions decay as $\tpiz \ra b \ol b$ and $\tpip \ra c \ol b$. Their production rates are resonantly enhanced by isovector technirho vector mesons with mass $M_W + M_{\tpi} \simle M_{\tro} \simle 2 M_{\tpi}$. At the Tevatron, these associated production rates are 1--10 picobarns for $M_{\tpi} \simeq 100\,\gev$. Such a low mass technipion requires topcolor-assisted technicolor to suppress th…
We study the process p bar{p} --> gamma gamma gamma as a signal for associated photon-technipion production at the Tevatron. This is a clean signature with relatively low background. Resonant and non-resonant contributions are included and we show that technicolor models can be effectively probed in this mode.
n this letter we investigate the various processes that can contribute to a final state consisting of a lepton, missing transverse momentum and two jets at Next to Leading Order (NLO) at the Tevatron. In particular we consider the production of W/Z + 2 jets, diboson pairs, single top and the tt process with both fully leptonic and semi-leptonic decays. We present distributions for the invariant mass of the dijet system and normalisations of the various processes, accurate to NLO.
Results from a phenomenological analysis of dijet and W hard diffractive hadroproduction at Fermilab Tevatron energies are reported. The theoretical framework employed here is a modified version of the Ingelman-Schlein approach which includes DGLAP-evolved structure functions. Different from what has been achieved by the DESY ep HERA reactions, a reasonable overall description of such diffractive hadron processes is obtained only when a complex, quark-rich Pomeron structure function is employed in the calculation.
We perform a detailed study of the process of single color octet isoscalar $η_T$ production at the Tevatron with $η_T \to γ+ g$ decay signature, including a complete simulation of signal and background processes. We determined a set of optimal cuts from an analysis of the various kinematical distributions for the signal and backgrounds. As a result we show the exclusion and discovery limits on the $η_T$ mass which could be established at the Tevatron for some technicolor models.
We present the first NLO QCD analysis of single-diffractive dijet production in proton-antiproton collisions. By comparing the ratio of single- and non-diffractive cross sections to data from the Tevatron, the rapidity-gap survival probability is determined as a function of the momentum fraction of the parton in the antiproton. Assuming Regge factorization, this probability can be interpreted as a suppression factor for the diffractive structure function measured in deep-inelastic scattering at HERA. In contrast to the observations for photoproduction, the suppression factor in proton-antiprot…
We perform a NLO QCD analysis of single-diffractive dijet production in proton-antiproton collisions. By comparing the ratio of single- and non-diffractive cross sections to data from the Tevatron, the rapidity-gap survival probability is determined as a function of the momentum fraction of the parton in the antiproton. Assuming Regge factorization, this probability can be interpreted as a suppression factor for the diffractive structure function measured in deep-inelastic scattering at HERA. In contrast to the observations for photoproduction, the suppression factor in proton-antiproton colli…
Recent new results on the determination of the rapidity dependence of the differential inclusive jet cross section, $<d^{2}σ/d\et dη>$, as a function of jet $E_{T}$ in \ppbar collisions at $\sqrt{s}=1800$ GeV, measured by the D0 detector at the Tevatron, are presented along with the comparisons to theoretical next-to-leading order (NLO) perturbative QCD predictions. Triple differential dijet cross sections, $<d^{3}σ/d\et dη_{1} dη_{2}>$, at $\sqrt{s}=1800$ GeV, as well as the new results on jet structure at $\sqrt{s}=1800$ and 630 GeV, as measured by the CDF and D0 detectors, are also discusse…
Hadronic processes in which hard diffractive production takes place have been observed and analyzed in collider experiments for several years. The experimental rates of diffractive W's and dijets measured at the Tevatron and the cross sections of diffractively produced dijets recently obtained at the HERA experiment are the object of this analysis. We use the Pomeron structure function obtained from the HERA data by two different approaches to calculate the rates and cross sections for these processes. The comparison of theoretical predictions with the measured values reveals some discrepancie…
In multiscale and topcolor-assisted models of walking technicolor, relatively light spin-one technihadrons $ρ_T$ and $ω_T$ exist and are expected to decay as $ρ_T \to W π_T, Z π_T$ and $ω_T \to γπ_T$. For $M_{ρ_T} \simeq 200 GeV$ and $M_{π_T} \simeq 100 GeV$, these processes have cross sections in the picobarn range in $\bar p p$ colisions at the Tevatron and about 10 times larger at the Large Hadron Collider. We demonstrate their detectability with simulations appropriate to Run II conditions at the Tevatron.
Events with one lepton, one photon and missing energy are the subject of recent searches at the Fermilab Tevatron. We compute possible contributions to these type of events from the process p pbar --> photon l nu_l nu_tau nubar_tau, where l=e,mu in the context of a Low Scale Technicolor Model. We find that with somewhat tighter cuts than the ones used in the CDF search, it could be possible to either confirm or exclude this model in a small region of its parameter space.
In this contribution we examine the transverse momentum distributions in dijet production at large rapidity intervals at the Tevatron, using the BFKL resummation.
In this talk we examine the azimuthal angle decorrelation in dijet production at large rapidity intervals at the Tevatron as a possible signature of the BFKL evolution.
I discuss production and detection at the Tevatron $\pbarp$ collider of pairs of light ($\mpi = 100$--$200\,\gev$) color--singlet technipions that are expected in all nonminimal models of technicolor. Gluon fusion production rates can be as large as $\CO(1\,\pb)$. Topcolor--assisted technicolor is required to prevent top quarks from decaying as $t \ra \tpip b$. An intriguing consequence of this is that the decays $\tpip \ra τ^+ ν_τ$, $c \ol s$ and $\tpiz \ra b \ol b$ may also be suppressed so that $\tpip \ra W^+ γ$ and $\tpiz \ra γγ$ are significant. These modes have spectactular signatures at…
In this paper, we discuss the observation of exclusive events using the dijet mass fraction as measured by the CDF collaboration at the Tevatron. We compare the data to pomeron exchange inspired models as well as Soft color interaction ones. We also provide the prediction on dijet mass fraction at the LHC using both exclusive and inclusive diffractive events.
New results from the CDF Collaboration on the invariant mass distribution of dijet events observed at the Tevatron are used to constrain the masses and couplings of new gauge bosons ($W'$ and $Z'$) as well as fundamental diquarks which can occur in some extended electroweak models. In the case of new gauge bosons, these new bounds are then compared to existing limits which arise from searches for the leptonic decay modes of these particles at the Tevatron.
We study the contributions of the neutral pseudo Goldstone bosons (technipions and top-pions) to the t anti-t production cross sections at the Tevatron and the LHC in topcolor-assisted multiscale technicolor (TOPCMTC) models via the gluon-gluon fusion process from the loop-level couplings between the pseudo Goldstone bosons and the gluons. The MRS set A' parton distributions are used in the calculation. It is shown that the new CDF datum on the t anti-t production cross section gives constraints on the parameters in the TOPCMTC models. With reasonable values of the parameters in TOPCMTC models…
Central production cross-sections of hard dijets with 2,1 or 0 rapidity gap at Tevatron are analyzed in terms of diffractive (``a la Good-Walker'') and non diffractive fluctuations of the incident particles. The observed large factorization breaking and the unexpected high value of the 2 to 1 gap cross-section ratio are explained in terms of scattering with and between the incident particles.
The effects of light, long-lived gluinos on $2\to 2$ processes at hadron colliders are examined. Such particles can mediate single squark resonant production via $q\glu\to\sq\to q\glu$ which would significantly modify the dijet data sample. We find that squark masses in the range $130<m_{\tilde q}< 694, 595, 573$ GeV are excluded for gluino masses of $0.4, 1.3, 5.0$ GeV from existing UA2 and Tevatron data on dijet bump searches and angular distributions. Run II of the Tevatron has the capability of excluding this scenario for squark masses up to $\sim 1$ TeV.
Dijet production at the Tevatron including effects of virtual exchanges of spin-2 Kaluza-Klein modes in theories with large extra dimensions is considered. The experimental dijet mass and angular distribution are exploited to obtain stringent limits ($\sim 1.2$ TeV) on the effective string scale $M_S$.
Exclusive dijet production at the Tevatron can be used as a benchmark to establish predictions on exclusive diffractive Higgs production, a process with a much smaller cross section. Exclusive dijet production in Double Pomeron Exchange processes, including diffractive Higgs production with measurements at the Tevatron and predictions for the Large Hadron Collider are presented. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Upper limits on the exclusive dijet production cross section …
Experimental results in diffractive processes are summarized and a few notable characteristics described in terms of Quantum Chromodynamics. Exclusive dijet production is used to establish a benchmark for future experiments in the quest for diffractive Higgs production at the Large Hadron Collider. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Stringent upper limits on the exclusive dijet production cross section are presented. The quark/gluon composition of dijet final states is used…
We explore the sensitivity of Tevatron data to heavy new physics effects in differential dijet production rates using the SMEFT in light of the fact that consistent and conservative constraints from the LHC cannot cover relatively low cutoff scales in the EFT. In contrast to the results quoted by the experimental collaborations and other groups, we find that, once consistency of the perturbation expansion is enforced and reasonable estimates of theoretical errors induced by the SMEFT series in $\frac{E}Λ$ are included, there is no potential to constrain four-quark contact interactions using Te…
We consider single squark production in $p\overline{p}$ collisions at $\sqrt{s}=1800$ Gev in the light gluino scenario, where production is dominated by the parton subprocess $qg\rightarrow \tilde{q}\tilde{g}\rightarrow q\tilde{g}\tilde{g}$. Computed are the total production cross-sections as well as the contribution of such production to the dijet mass distribution. We compare our cross-sections to the experimental data from the CDF collaboration with integrated luminosity of $19 pb^{-1}$.
Recently has been shown that the physical (mass eigenstate) color-octet technirho does not couple to two gluons. In this letter we study how this result affects the presently accepted limits for the color-octet technirho mass obtained from the study of dijets production at the Tevatron. First we show that data from Tevatron Run 1b can not exclude any mass range. Finally, we obtain limits for the Tevatron Run II.
Resonant production of a light, narrow techni-rho, followed by the decay $ρ_T \rightarrow W+π_T(jj)$ has been proposed as an explanation of the Wjj excess observed by CDF. If the $π_T$ decays to $τ+ν/τ^+ τ^-$ rather than to jets, subsequent leptonic $τ$ decay leads to $\ell^+\ell^- νν\barν\barν$, a final state that will be picked up by standard model $WW^{(*)} \rightarrow \ell^+\ell^-$ + MET Higgs searches. We point out that, for the same range of technicolor parameters required to fit the CDF Wjj excess, the correlated $\ell^+\ell^-$ + MET technicolor signal can have strength comparable to th…
Pair-production of heavy top quarks at the Tevatron Collider is significantly enhanced by the color--octet technipion, $η_T$, occurring in multiscale models of walking technicolor. We discuss $\bar tt$ rates for $m_t = 170$ GeV and $M_{η_T} = 400-500$ GeV. Multiscale models also have color--octet technirho states in the mass range 200-600 GeV that appear as resonances in dijet production and technipion pair--production.
Strategies are presented for discovering light, color-singlet technipions (pi_T) produced in association with a vector boson through s-channel technirho production, at the Tevatron and LHC. Signal and W+jets background were simulated including detector effects. Tagging of b-quarks from the pi_T -> bb decay is found to be important to reduce the W+jets background. Kinematic properties of signal and background events are significantly different and simple cuts can be used to further improve the signal to background ratio.
We describe new QCD fits to diffractive proton structure functions measured at HERA, and we use these parton densities to predict the shape of the dijet mass fraction at the Tevatron and look for the existence of exclusive events in the dijet channel.
We describe new QCD fits to diffractive cross sections measured at HERA and we use the parton densities derived from these fits to predict the shape of the dijet mass fraction in double Pomeron exchange at the Tevatron. We discuss the existence of exclusive events in this dijet channel and some prospects are given for the LHC.
We study in detail the model by Isidori and Kamenik that is claimed to explain the top quark forward-backward asymmetry at Tevatron, provide GeV-scale dark matter (DM), and possibly improve the agreement between data and theory in Tevatron W+jj events. We compute the DM thermal relic density, the spin-independent DM-nucleon scattering cross section, and the cosmic microwave background constraints on both Dirac and Majorana neutralino DM in the parameter space that explains the top asymmetry. A stable light neutralino is not allowed unless the local DM density is 3-4 times smaller than expected…
The recent observation by the CDF Collaboration of an excess in $W$ plus dijet events, where the dijet invariant mass shows a 3.2$σ$ peak around $144 \pm 5$ GeV, is shown to be consistent with the production of a radion $Φ$ of mass in this range, in association with a $W$ boson. It is shown that the $Φ$, which is known to be similar to the Higgs boson in many aspects, differs from it in having a much larger cross-section for $q\bar q \to WΦ$ and in decaying principally to gluons, rather than $b\bar b$ pairs. These appear to be the precise features demanded by the new particle interpretation of…
In multiscale and topcolor-assisted models of walking technicolor, light, spin-one technihadrons can exist with masses of a few hundred GeV; they are expected to decay as rho_T -> W pi_T. For technirho masses ~200 GeV and technipion masses ~100 GeV, the process pbar p -> rho_T -> W pi_T has a cross section of about a picobarn at the Tevatron. We demonstrate the detectability of this process with simulations appropriate to Run II conditions, for the challenging case where the technipion decays dominantly into two gluons.
We discuss the recent excess seen by the CDF Collaboration in the dijet invariant mass distribution produced in association with a $W$ boson. We analyze the possibility of such a signal within the context of a $U(1)_X$ Stueckelberg extension of the Standard Model where the new gauge boson couples only to quarks. In addition to the analysis of the $Wjj$ anomaly we also discuss the production of $Zjj$ and $γjj$ at the Tevatron. The analysis is then extended to the Large Hadron Collider with $\sqrt{s}=7 {\rm TeV}$ and predictions for the dijet signals are made.
The CDF collaboration has reported a 4.1σ excess in their lepton, missing energy, and dijets channel. This excess, which takes the form of an approximately Gaussian peak centered at a dijet invariant mass of 147 GeV, has provoked a great deal of experimental and theoretical interest. Although the DØ collaboration has reported that they do not observe a signal consistent with CDF, there is currently no widely accepted explanation for the discrepancy between these two experiments. A resolution of this issue is of great importance---not least because it may teach us lessons relevant for future se…
We present the calculation of the most important electroweak corrections to dijet production at the LHC and the Tevatron, comprising tree-level effects of O(α_sα,α^2) and weak loop corrections of O(α_s^2α). Although negligible for integrated cross sections, these corrections can reach 10-20% in the TeV range for transverse jet momenta k_T. Our detailed discussion of numerical results comprises distributions in the dijet invariant mass and in the transverse momenta of the leading and subleading jets. We find that the weak loop corrections amount to about -12% and -10% for leading jets with k_T~…
In a topcolor-assisted technicolor model (TC2) with large FCNC top quark couplings, we study its correlated contributions to the top quark forward-backward asymmetry ($A_{FB}$) at the Tevatron, the top charge asymmetry ($A_{C}$) and the triple-top production at the LHC. Under current constraints on the top quark from the LHC and Tevatron(such as the total and differential production rates), we scan the parameter space of such a TC2 model. We find that in the allowed parameter space the TC2 model can explain the Tevatron measured $A_{FB}$ at $2σ$ level, but meanwhile significantly enhance $A_{C…
The newly found \cite{CDFnew} dijet peak in the 120 GeV to 160 GeV mass region produced in co-production with W IS actually a Higgs Boson in spite of the expectation of a different decay pattern for most Higgses. Our point, however, is that the bound state of 6t + 6$\bar{t}$, which we have put forward already in several articles \cite{boundfirst}\cite{bound} \cite{dark}\cite{hierarchybound}, easily could be lighter - possibly much lighter - than half the Higgs mass. Higgs would in this case decay dominantly to two of our bound states. If these bound states were indeed very light (say around 10…
In topcolor assisted technicolor, topgluons are massive gluons which couple mainly to top and bottom quarks. We estimate the mass reach for topgluons decaying to t anti-t at the Tevatron as a function of integrated luminosity. The mass reach for topgluons decreases with increasing topgluon width, and is 1.0 - 1.1 TeV for Run II (2 fb^-1) and 1.3-1.4 TeV for TeV33 (30 fb^-1).
In topcolor assisted technicolor, topgluons are massive gluons which couple mainly to top and bottom quarks. We estimate the mass reach for topgluons decaying to b anti-b at the Tevatron as a function of integrated luminosity. The mass reach for topgluons decreases with increasing topgluon width, and is 0.77 - 0.95 TeV for Run II (2 fb^-1) and 1.0-1.2 TeV for TeV33 (30 fb^-1).
Diffractive production of the Higgs boson at hadron colliders is discussed in the light of the observed rate of hard diffractive dijet events at the Tevatron. The Higgs predictions of models successful for dijets are compared. LHC seems promising for a diffractive light Higgs boson and its mass determination. Hard diffractive dijets, diphotons and dileptons at the Tevatron (Run II) will be necessary to remove the remaining large uncertainties on cross-sections and signals.
We explore the diffractive interaction of a proton with an anti-proton which results in centrally produced dijets. This process has been recently studied at the Tevatron. We make predictions within an Ingelman-Schlein approach and compare them to the recent data presented by the CDF collaboration. Earlier calculations resulted in theoretical cross-sections which are much larger than those observed by CDF. We find that, after consideration of hadronisation effects and the parton shower, and using parton density functions extracted from diffractive deep inelastic scattering at HERA, it is possib…
We present and discuss two different topics where Tevatron and HERA data can be compared directly. A method allowing for a direct comparison of data with theoretical predictions is proposed for forward jet production at HERA. An application to the determination of the effective Pomeron intercept in the BFKL-LO parametrization from $dσ/dx$ data at HERA leads to a good fit with a significantly high effective intercept, $α_P= 1.43 \pm 0.025 (stat.) \pm 0.025 (syst.)$. It is less than the value of the pomeron intercept using dijets with large rapidity intervals obtained at Tevatron. In a second pa…
We perform a phenomenological analysis of dijet production in double pomeron exchange at the Tevatron. We find that the CDF Run I results do not rule out the presence of an exclusive dijet component, as predicted by Khoze, Martin and Ryskin (KMR). With the high statistics CDF Run II data, we predict that an exclusive component at the level predicted by KMR may be visible, although the observation will depend on accurate modelling of the inclusive double pomeron exchange process. We also compare to the predictions of the DPEMC Monte Carlo, which contains a non-perturbative model for the central…
We show that the hadroproduction of a pair of jets with large transverse energy in the central region bounded by rapidity gaps is an ideal process to see important double logarithmic QCD suppression effects. We compute the cross sections for both exclusive and inclusive double-diffractive dijet production at Tevatron and LHC energies for a range of rapidity configurations.
We propose a particularly simple explanation of the W+dijet excess reported by the CDF collaboration. No symmetries beyond those of the standard model are necessary, and the only new particles involved are a spin-zero weak SU(2) doublet with no vacuum expectation value. Possible tests of the model and comparisons to other proposals are discussed.
For an attractive class of dynamical symmetry breaking (technicolor) models, the lightest neutral pseudo-Nambu-Goldstone boson ($\pzero$) contains only down-type techniquarks and charged technileptons. We discuss the prospects for discovering and studying the $\pzero$ of such models at the Tevatron and the LHC and at future $\epem$ and $\mupmum$ colliders. Depending upon the number of technicolors, $\ntc$, discovery of the $\pzero$ at the Tevatron and the LHC in the $gg\to\pzero\to\gam\gam$ mode could be possible over a wide range of mass. For $\ntc=4$, discovery of the $\pzero$ at an $\epem$ …
The latest CDF anomaly, the excess of dijet events in the invariant-mass window 120-160 GeV in associated production with a $W$ boson, can be explained by a baryonic $Z'$ model in which the $Z'$ boson has negligible couplings to leptons. Although this $Z'$ model is hardly subject to the Drell-Yan constraint from Tevatron, it is constrained by the dijet data from UA2 ($\sqrt{s} = 630$ GeV), and the precision measurements at LEP through the mixing with the SM $Z$ boson. We show that under these constraints this model can still explain the excess in the M_{jj} \sim 120 - 160 GeV window, as well a…
The ATLAS collaboration has recently reported an excess of about 2.5 $σ$ global significance at around 2 TeV in the diboson channel with the boson-tagged fat dijets, which may imply a new resonance beyond the standard model. We provide a possible explanation of the excess as the isospin-triplet technivector mesons (technirhos, denoted as $ρ_Π^{\pm,3}$) of the walking technicolor in the case of the one-family model as a benchmark. As the effective theory for the walking technicolor at the scales relevant to the LHC experiment, we take a scale-invariant version of the hidden local symmetry model…
We examine dijet production at large rapidity intervals at Tevatron energies, by using the theory of Lipatov and collaborators which resums the leading powers of the rapidity interval. We analyze the growth of the Mueller-Navelet $K$-factor in this context and find it to be negligible. However, we do find a considerable enhancement of jet production at large transverse momenta. In addition, we show that the correlation in transverse momentum and azimuthal angle of the tagging jets fades away as the rapidity interval is increased.
We consider the production of high invariant mass jet pairs at hadron colliders as a test for TeV scale gravitational effects. We find that this signal can probe effective Planck masses of about 10 TeV at the LHC with center of mass energy of 14 TeV and 1.5 TeV at the Tevatron with center of mass energy of 2 TeV. These results are compared to analogous scattering processes at leptonic colliders.
Hypothetical color-octet particles of spin 0, pair-produced at hadron colliders through their QCD coupling, may lead to final states involving three or four b jets. We analyze kinematic distributions of the 3b final state that differentiate the scalar octets from supersymmetric Higgs bosons. Studying the scalar sector that breaks an SU(3) \times SU(3) gauge symmetry down to the QCD gauge group, we find that the scalar octet is resonantly produced in pairs via a spin-1 octet (coloron). A scalar octet of mass in the 140 - 150 GeV range can explain the nonstandard shape of the b-jet transverse en…
The invariant mass distribution of dijets produced in association with W bosons, recently observed by the CDF Collaboration at Tevatron, reveals an excess in the dijet mass range 120-160 GeV/c^2, 3σbeyond Standard Model expectations. We show that such an excess is a generic feature of low mass string theory, due to the production and decay of a leptophobic Z', a singlet partner of SU(3) gluons coupled primarily to the U(1) baryon number. In this framework, U(1) and SU(3) appear as subgroups of U(3) associated with open strings ending on a stack of 3 D-branes. In addition, a minimal model conta…
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