Discovery potential for supersymmetry at a high luminosity upgrade of LHC14

After completion of the LHC8 run in 2012, the plan is to upgrade the LHC for operation close to its design energy root 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 supersymmetry in the mSUGRA/CMSSM model with an anticipated high luminosity upgrade. We find that LHC14 with 300 (3000) fb(-1) has a reach for supersymmetry via gluino/squark searches of m((g) over tilde) similar to 3.2 TeV (3.6 TeV) for m((q) over tilde) similar to m((g) over tilde), and a reach of m((g) over tilde) similar to 1.8 TeV (2.3 TeV) for m((q) over tilde) >> m((g) over tilde). In the case where m((q) over tilde) >> m((g) over tilde), then the LHC14 reach for chargino-neutralino production with decay into the Wh + 6 is not an element of(T) final state reaches to m((g) over tilde) similar to 2.6 TeV for 3000 fb(-1).

Wh plus missing-E-T signature from gaugino pair production at the LHC

In SUSY models with heavy squarks and gaugino mass unification, the gaugino pair production reaction pp -> (W) over tilde (+/-)(1)(Z) over tilde (2) dominates gluino pair production for m (g) over tilde less than or similar to 1 TeV at LHC with root s = 14 TeV (LHC14). For this mass range, the two-body decays (W) over tilde (1) -> W (Z) over tilde (1) and (Z) over tilde (2) -> h (Z) over tilde (1) are expected to dominate the chargino and neutralino branching fractions. By searching for lb (b) over tilde + is not an element of(T) events from (W) over tilde (+/-)(1)Z(2) production, we show that LHC14 with 100 fb(-1) of integrated luminosity becomes sensitive to chargino masses in the range m((W) over tilde1) similar to 450-550 GeV corresponding to m (g) over tilde similar to 1.5-2 TeV in models with gaugino mass unification. For 10(3) fb(-1), LHC14 is sensitive to the Wh channel for m((W) over tilde1) similar to 300-800 GeV, corresponding to m (g) over tilde similar to 1-2.8 TeV, which is comparable to the reach for gluino pair production followed by cascade decays. The Wh + is not an element of(T) search channel opens up a new complementary avenue for SUSY searches at LHC, and serves to point to SUSYas the origin of any new physics discovered via multijet and multilepton + is not an element of(T) channels.

W Z plus missing-E-T signal from gaugino pair production at LHC7

LHC searches for supersymmetry currently focus on strongly produced sparticles, which are copiously produced if gluinos and squarks have masses of a few hundred GeV. However, in supersymmetric models with heavy scalars, as favored by the decoupling solution to the SUSY flavor and CP problems, and m((g) over tilde) greater than or similar to 500 GeV as indicated by recent LHC results, chargino-neutralino ((W) over tilde (+/-)(1)(Z) over tilde (2)) production is the dominant cross section for m((W) over tilde1) similar to m((Z) over tilde2) < m(<(g)over tilde>)/3 at LHC with root s = 7 TeV (LHC7). Furthermore, if m((Z) over tilde1) + (m (Z) over tilde) less than or similar to m((Z) over tilde2) less than or similar to m((Z) over tilde1) + m(h), then (Z) over tilde (2) dominantly decays via (Z) over tilde (2) -> (Z) over tilde (1)Z, while (W) over tilde (1) decays via (W) over tilde (1) -> (Z) over tilde W-1. We investigate the LHC7 reach in the W Z + (sic)T channel (for both leptonic and hadronic decays of the W boson) in models with and without the assumption of gaugino mass universality. In the case of the mSUGRA/CMSSM model with heavy squark masses, the LHC7 discovery reach in the W Z+ (sic)T channel becomes competetive with the reach in the canonical (sic)T + jets channel for integrated luminosities similar to 30 fb(-1). We also present the LHC7 reach for a simplified model with arbitrary m((Z) over tilde1) and m((W) over tilde1) similar to m((Z) over tilde2). Here, we find a reach of up to m((W) over tilde1) similar to 200 (250) GeV for 10 (30) fb(-1).

LHC discovery potential for supersymmetry with root s=7 TeV and 5-30 fb(-1)

We extend our earlier results delineating the supersymmetry reach of the CERN Large Hadron Collider operating at a center-of-mass energy root s = 7 TeV to integrated luminosities in the range 5-30 fb(-1). Our results are presented within the paradigm minimal supergravity model or constrained minimal supersymmetric standard model. Using a six-dimensional grid of cuts for the optimization of signal to background ratio-including missing E-T-we find for m((g) over tilde) similar to m((q) over tilde) an LHC 5 sigma supersymmetry discovery reach of m((g) over tilde) similar to 1:3, 1.4, 1.5, and 1.6 TeV for 5, 10, 20, and 30 fb(-1), respectively. For m((q) over tilde) >> m((g) over tilde), the corresponding reach is instead m((g) over tilde) similar to 0: 8, 0.9, 1.0, and 1.05 TeV, for the same integrated luminosities.

First Observation of Vector Boson Pairs in a Hadronic Final State at the Tevatron Collider

We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V=W, Z) where one boson decays to a dijet final state. The data correspond to 3.5  fb-1 of integrated luminosity of pp̅ collisions at √s=1.96  TeV collected by the CDF II detector at the Fermilab Tevatron. We observe 1516±239(stat)±144(syst) diboson candidate events and measure a cross section σ(pp̅ →VV+X) of 18.0±2.8(stat)±2.4(syst)±1.1(lumi)  pb, in agreement with the expectations of the standard model.

First Observation of Vector Boson Pairs in a Hadronic Final State at the Tevatron Collider

We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V=W,Z) where one boson decays to a dijet final state . The data correspond to 3.5 inverse femtobarns of integrated luminosity of ppbar collisions at sqrt(s)=1.96 TeV collected by the CDFII detector at the Fermilab Tevatron. We observe 1516+/-239(stat)+/-144(syst) diboson candidate events and measure a cross section sigma(ppbar->VV+X) of 18.0+/-2.8(stat)+/-2.4(syst)+/-1.1(lumi) pb, in agreement with the expectations of the standard model.

Wgamma production and limits on anomalous WWgamma couplings in ppbar collisions

We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W -> lnu+gamma production in egamma and mugamma final states. Using data corresponding to an integrated luminosity of 4.2 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider, the cross section multiplied by the branching fraction for the process ppbar -> Wgamma+X -> lnugamma+X, measured to be 15.8 +/- 0.8 (stat.) +/- 1.2 (syst.) pb, and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WWgamma couplings for data from hadron colliders: -0.4 < Delta kappa_gamma < 0.4 and -0.08 < lambda_gamma < 0.07 at the 95% C.L.

Working group report: Dictionary of Large Hadron Collider signatures

We report on a plan to establish a `Dictionary of LHC Signatures', an initiative that started at the WHEPP-X workshop in Chennai, January 2008. This study aims at the strategy of distinguishing 3 classes of dark matter motivated scenarios such as R-parity conserved supersymmetry, little Higgs models with T-parity conservation and universal extra dimensions with KK-parity for generic cases of their realization in a wide range of the model space. Discriminating signatures are tabulated and will need a further detailed analysis.

Use of transverse beam polarization to probe anomalous V V H interactions at a Linear Collider

We investigate use of transverse beam polarization in probing anomalous coupling of a Higgs boson to a pair of vector bosons, at the International Linear Collider (ILC). We consider the most general form of V V H (V = W/Z) vertex consistent with Lorentz invariance and investigate its effects on the process e(+)e(-) -> f (f) over barH, f being a light fermion. Constructing observables with definite C P and naive time reversal ((T) over tilde) transformation properties, we find that transverse beam polarization helps us to improve on the sensitivity of one part of the anomalous Z Z H Coupling that is odd under C P. Even more importantly it provides the possibility of discriminating from each other, two terms in the general Z Z H vertex, both of which are even under C P and (T) over bar. Use of transversebeam polarization when combined with information from unpolarized and linearly polarized beams therefore, allows one to have completely independent probes of all the different parts of a general ZZH vertex.

Production of psi(2S) Mesons in ppbar Collisions at 1.96 TeV

We have measured the differential cross section for the inclusive production of psi(2S) mesons decaying to mu^{+} mu^{-1} that were produced in prompt or B-decay processes from ppbar collisions at 1.96 TeV. These measurements have been made using a data set from an integrated luminosity of 1.1 fb^{-1} collected by the CDF II detector at Fermilab. For events with transverse momentum p_{T} (psi(2S)) > 2 GeV/c and rapidity |y(psi(2S))| psi(2S)X) Br(psi(2S) -> mu^{+} mu^{-}) to be 3.29 +- 0.04(stat.) +- 0.32(syst.) nb.

Search for exclusive Z boson production and observation of high mass ppbar->gammagamma->p+ll+pbar events in ppbar collisions at sqrt(s) = 1.96 TeV

We present a search for exclusive Z boson production in proton-antiproton collisions at sqrt(s) = 1.96 TeV, using the CDF II detector at Fermilab. We observe no exclusive Z->ll candidates and place the first upper limit on the exclusive Z cross section in hadron collisions, sigma(exclu) gammagamma->p+ll+pbar, and measure the cross section for M(ll) > 40 GeV/c2 and |eta(l)|

Search for new physics in the μμ+e/μ+E̸T channel with a low-pT lepton threshold at the Collider Detector at Fermilab

A search for new physics using three-lepton (trilepton) data collected with the CDF II detector and corresponding to an integrated luminosity of 976 pb-1 is presented. The standard model predicts a low rate of trilepton events, which makes some supersymmetric processes, such as chargino-neutralino production, measurable in this channel. The mu+mu+l signature is investigated, where l is an electron or a muon, with the additional requirement of large missing transverse energy. In this analysis, the lepton transverse momenta with respect to the beam direction (pT) are as low as 5 GeV/c, a selection that improves the sensitivity to particles which are light as well as to ones which result in leptonically decaying tau leptons. At the same time, this low-p_T selection presents additional challenges due to the non-negligible heavy-quark background at low lepton momenta. This background is measured with an innovative technique using experimental data. Several dimuon and trilepton control regions are investigated, and good agreement between experimental results and standard-model predictions is observed. In the signal region, we observe one three-muon event and expect 0.4+/-0.1 mu+mu+l events

Measurement of the top quark mass and pp̅ →tt̅ cross section in the all-hadronic mode with the CDF II detector

We present a measurement of the top quark mass and of the top-antitop pair production cross section using p-pbar data collected with the CDFII detector at the Tevatron Collider at the Fermi National Accelerator Laboratory and corresponding to an integrated luminosity of 2.9 fb-1. We select events with six or more jets satisfying a number of kinematical requirements imposed by means of a neural network algorithm. At least one of these jets must originate from a b quark, as identified by the reconstruction of a secondary vertex inside the jet. The mass measurement is based on a likelihood fit incorporating reconstructed mass distributions representative of signal and background, where the absolute jet energy scale (JES) is measured simultaneously with the top quark mass. The measurement yields a value of 174.8 +- 2.4(stat+JES) ^{+1.2}_{-1.0}(syst) GeV/c^2, where the uncertainty from the absolute jet energy scale is evaluated together with the statistical uncertainty. The procedure measures also the amount of signal from which we derive a cross section, sigma_{ttbar} = 7.2 +- 0.5(stat) +- 1.0 (syst) +- 0.4 (lum) pb, for the measured values of top quark mass and JES.

Observation of single top quark production and measurement of |Vtb| with CDF

We report the observation of electroweak single top quark production in 3.2  fb-1 of pp̅ collision data collected by the Collider Detector at Fermilab at √s=1.96  TeV. Candidate events in the W+jets topology with a leptonically decaying W boson are classified as signal-like by four parallel analyses based on likelihood functions, matrix elements, neural networks, and boosted decision trees. These results are combined using a super discriminant analysis based on genetically evolved neural networks in order to improve the sensitivity. This combined result is further combined with that of a search for a single top quark signal in an orthogonal sample of events with missing transverse energy plus jets and no charged lepton. We observe a signal consistent with the standard model prediction but inconsistent with the background-only model by 5.0 standard deviations, with a median expected sensitivity in excess of 5.9 standard deviations. We measure a production cross section of 2.3-0.5+0.6(stat+sys)  pb, extract the value of the Cabibbo-Kobayashi-Maskawa matrix element |Vtb|=0.91-0.11+0.11(stat+sys)±0.07  (theory), and set a lower limit |Vtb|>0.71 at the 95% C.L., assuming mt=175  GeV/c2.