We present a search for associated production of the standard model (SM) Higgs boson and a $Z$ boson where the $Z$ boson decays to two leptons and the Higgs decays to a pair of $b$ quarks in $p\bar{p}$ collisions at the Fermilab Tevatron. We use event probabilities based on SM matrix elements to construct a likelihood function of the Higgs content of the data sample. In a CDF data sample corresponding to an integrated luminosity of 2.7 fb$^{-1}$ we see no evidence of a Higgs boson with a mass between 100 GeV$/c^2$ and 150 GeV$/c^2$. We set 95% confidence level (C.L.) upper limits on the cross-section for $ZH$ production as a function of the Higgs boson mass $m_H$; the limit is 8.2 times the SM prediction at $m_H = 115$ GeV$/c^2$.
We present the results of searches for the standard model Higgs boson at CDF in final states with bottom quarks. Results are derived from the complete Tevatron Run II dataset, with a measured integrated luminosity of 9.5 fb$^{-1}$ of proton-antiproton data. The searches are performed for assumed Higgs masses between 90 and 150 GeV, for Higgs bosons produced in association with W or Z bosons. Employing several improved techniques, these are currently the most sensitive searches in the world for these processes, surpassing previous CDF results by 30% beyond what would be expected from the additi…
A search is presented for the standard model Higgs boson produced in association with top quarks using the full Run II proton-antiproton collision data set, corresponding to 9.45 inverse fb, collected by the Collider Detector at Fermilab. No significant excess over the expected background is observed, and 95% credibility-level upper bounds are placed on the cross section sigma(t\bar{t}H --> lepton + missing transverse energy + jets). For a Higgs boson mass of 125 GeV, we expect to set a limit of 12.6, and observe a limit of 20.5 times the standard model rate. This represents the most sensitive…
We present a search for standard model Higgs boson production in association with a W boson in proton-antiproton collisions ($p\bar{p}\to W^\pm H \to \ellνb\bar{b}$) at a center of mass energy of 1.96 TeV. The search employs data collected with the CDF II detector which correspond to an integrated luminosity of approximately 1 fb-1. We select events consistent with a signature of a single lepton ($e^\pm/μ^\pm$), missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with a secondary vertex tagging method and a neural network filter technique. The observed n…
We report on a study of the dijet invariant-mass distribution in events with one identified lepton, a significant imbalance in the total event transverse momentum, and two jets. This distribution is sensitive to the possible production of a new particle in association with a $W$ boson, where the boson decays leptonically. We use the full data set of proton-antiproton collisions at 1.96 TeV center-of-mass energy collected by the Collider Detector at the Fermilab Tevatron and corresponding to an integrated luminosity of 8.9 fb$^{-1}$. The data are found to be consistent with standard-model expec…
We present a search for anomalous semileptonic decays of heavy flavor hadrons produced in association with a $W$ boson, in proton-antiproton collisions at sqrt{s}=1.96 TeV. We use 162 pb-1 of data collected with the CDF II detector at the Fermilab Tevatron Collider. We select events with one W boson and at least one jet with an identified secondary vertex. In the jets with a secondary vertex we look for a semileptonic decay to a muon. We compare the number of jets with both a secondary vertex and a semileptonic decay, and the kinematic properties of these jets, with the standard model expectat…
We present a search for technicolor particles decaying into $b\bar b$, $b\bar c$ or $b\bar u$ and produced in association with $W$ bosons in $p\bar p$ collisions at $\sqrt{s}= 1.96 \mathrm{TeV}$. The search uses approximately $1.9 \mathrm{fb}^{-1}$ of the dataset accumulated in the CDF II detector at the Fermilab Tevatron. We select events matching the $W$ + 2-jets signature and require at least one jets to be identified as $b$-quark jets. In the case of exactly one vertex $b$-tagged events, we apply a neural network flavor separator to reject contamination from charm and light quark jets. The…
Production of the Upsilon(1S) meson in association with a vector boson is a rare process in the standard model with a cross section predicted to be below the sensitivity of the Tevatron. Observation of this process could signify contributions not described by the standard model or reveal limitations with the current non-relativistic quantum-chromodynamic models used to calculate the cross section. We perform a search for this process using the full Run II data set collected by the CDF II detector corresponding to an integrated luminosity of 9.4/fb. The search considers the Upsilon(1S) to di-mu…
We present a search for the technicolor particles $ρ_{T}$ and $π_{T}$ in the process $p\bar{p} \to ρ_{T} \to Wπ_{T}$ at a center of mass energy of $\sqrt{s}=1.96 \mathrm{TeV}$. The search uses a data sample corresponding to approximately $1.9 \mathrm{fb}^{-1}$ of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is $W\to \ellν$ and $π_{T} \to b\bar{b}, b\bar{c}$ or $b\bar{u}$ depending on the $π_{T}$ charge. We select events with a single high-$p_T$ electron or muon, large missing transverse energy, and two jets. Jets correspondi…
Direct (prompt) photon production is a field of very high interest in hadron colliders. It provides probes to search for new phenomena and to test QCD predictions. In this article, two recent cross-section results for direct photon production using the full CDF Run II data set are presented: diphoton production and photon production in association with a heavy quark.
We propose an experimental test to verify the unexpected excess at Mjj=150GeV presented by the CDF collaboration in the invariant mass distribution of jet pairs produced in association with a W boson. We propose a formation experiment in which the energy range of the Mjj excess is scanned with proton-antiproton interactions at the Tevatron.
We present a search for the Standard Model Higgs boson produced in association with a Z or a W boson, using data collected with the CDF II detector at the Tevatron accelerator. A scenario where the Z decays into neutrinos or leptons originating from the W-decay escape detection and the Higgs decays into a $b\overline{b}$ pair is considered. Therefore the expected signature is large missing transverse energy ($\etmiss$), no isolated leptons, and two b-jets. We present the preliminary results in this search using 2.1$fb^{-1}$ of data collected by CDF.
We report the latest result for the search for the standard model higgs produced in association with a W and a Z boson at CDF. The results include about 1 to 1.7 fb-1 of data collected by CDF in run II of the Tevatron. Novel analysis techniques have been developed to enhance the sensitivity of these searches.
We present a search for the standard model Higgs boson produced in association with a $W^{\pm}$ boson. This search uses data corresponding to an integrated luminosity of 7.5 fb$^{-1}$ collected by the CDF detector at the Tevatron. We select $WH \to \ellνb \bar{b}$ candidate events with two jets, large missing transverse energy, and exactly one charged lepton. We further require that at least one jet be identified to originate from a bottom quark. Discrimination between the signal and the large background is achieved through the use of a Bayesian artificial neural network. The number of tagged …
We present a search for the Standard Model Higgs boson produced in association with a Z or a W boson, using data collected with the CDF II detector at the Tevatron accelerator. A scenario where the Z decays into neutrinos or charged leptons originating from the W-decay escape detection and the Higgs decays into a $b\overline{b}$ pair is considered. Therefore the expected signature is large missing transverse energy ($\etmiss$), no isolated leptons, and two $b$-jets. We present the preliminary results in this search using 1.7$fb^{-1}$ of data collected by CDF and the work on future improvements…
We report a measurement of the top quark mass $M_t$ in the dilepton decay channel $t\bar{t}\to b\ell'^{+}ν'_\ell\bar{b}\ell^{-}\barν_{\ell}$. Events are selected with a neural network which has been directly optimized for statistical precision in top quark mass using neuroevolution, a technique modeled on biological evolution. The top quark mass is extracted from per-event probability densities that are formed by the convolution of leading order matrix elements and detector resolution functions. The joint probability is the product of the probability densities from 344 candidate events in 2.0 …
We report a measurement of the top quark mass, M_t, in the dilepton decay channel of $t\bar{t}\to b\ell'^{+}ν_{\ell'}\bar{b}\ell^{-}\barν_{\ell}$ using an integrated luminosity of 1.0 fb^{-1} of p\bar{p} collisions collected with the CDF II detector. We apply a method that convolutes a leading-order matrix element with detector resolution functions to form event-by-event likelihoods; we have enhanced the leading-order description to describe the effects of initial-state radiation. The joint likelihood is the product of the likelihoods from 78 candidate events in this sample, which yields a mea…
The latest D0 and CDF measurements of the important $W+{\rm jets}$ and $Z/γ^{*}+{\rm jets}$ processes are described, along with a discussion of the comparisons that have been made to LO and NLO perturbative QCD predictions.
We describe a measurement of the top quark mass using events with two charged leptons collected by the CDF II detector from $p\bar{p}$ collisions with $\sqrt s = 1.96$ TeV at the Fermilab Tevatron. The likelihood in top mass is calculated for each event by convoluting the leading order matrix element describing $q\bar{q} \to t\bar{t} \to b\ellν_{\ell}\bar{b}\ell'ν_{\ell'}$ with detector resolution functions. The presence of background events in the data sample is modeled using similar calculations involving the matrix elements for major background processes. In a data sample with integrated lu…
The recently updated measurement of the $W$-boson mass by the CDF collaboration exhibits a $7σ$ deviation from the SM expectation, which may imply a sign of new physics beyond the SM. The observed discrepancy could be explained by new fermions that carry the electroweak gauge charges and affect the vacuum polarization of gauge bosons. Notably, if the new fermions also have the same quantum numbers as of the SM quarks, they can mix with the latter and thus modify the penguin diagrams governing the $b \to s \ell^+ \ell^-$ transitions. Therefore, the $W$-boson mass shift could be related to the $…
The CDF collaboration reported an excess in the production of two jets in association with a $W$. We discuss constraints on possible new particle state interpretations of this excess. The fact of no statistically significant deviation from the SM expectation for {$Z$+dijet} events in CDF data disfavors the new particle explanation. We show that the nucleon intrinsic strange quarks provide an important contribution to the $W$ boson production in association with a single top quark production. Such {$W$+t} single top quark production can contribute to the CDF {$W$+dijet} excess, thus the nucleon…
We report on two spectroscopy results from CDF. First, we observe the orbitally excited $B^{**}$ mesons in $B \to \ell D^{(*)}X$ events. We find $28 \pm 6 \pm 3$% of light $B$ mesons produced are $B^{**}$ states. A collective mass fit results in a $B_1$ mass of $5.71 \pm 0.02$ GeV/$c^2$. Secondly, we observe $20.4^{+6.2}_{-5.5}$ decays of $B^+_c \to J/ψ\ell^+X$, with a $ 6.40 \pm 0.39 \pm 0.13 {\rm GeV}/c^2$ mass and $ 0.46 ^{+0.18}_{-0.16} \pm 0.03 $ps lifetime. The production rate is in reasonable accordance with expectations.
The cross section for the inclusive production of W bosons in association with jets in ppbar collisions at sqrt(s)=1.96 TeV using the Collider Detector at Fermilab (CDF II) is presented. The measurement is based on an integrated luminosity of 320pb^-1, and includes events with up to 4 or more jets. In each jet multiplicity sample the differential and cumulative cross sections with respect to the transverse energy of the i^th-jet are measured. For W+>=2 jets the differential cross section with respect to the 2-leading jets invariant mass m_j1j2 and angular separation Delta R_j1j2 is also report…
We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H -> bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a limit of 7.1 (3.9) times the standard model value.
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 combine the results of searches for the standard model Higgs boson based on the full CDF Run II data set obtained from sqrt(s) = 1.96 TeV p-pbar collisions at the Fermilab Tevatron corresponding to an integrated luminosity of 9.45/fb. The searches are conducted for Higgs bosons that are produced in association with a W or Z boson, have masses in the range 90-150 GeV/c^2, and decay into bb pairs. An excess of data is present that is inconsistent with the background prediction at the level of 2.5 standard deviations (the most significant local excess is 2.7 standard deviations).
We report a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3 fb^-1. The observed distribution has an excess in the 120-160 GeV/c^2 mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In this letter we report studies of the properties of this excess.
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…
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_…
We present a search for the standard model Higgs boson produced in association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45 fb-1. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H->bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) t…
We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at $\sqrt{s} = 1.96$ TeV recorded by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45 fb$^{-1}$. We consider events having no identified charged lepton, a transverse energy imbalance, and two or three jets, of which at least one is consistent with originating from the decay of a $b$ quark. We place 95% credibility level upper limits on the production cross section times standard model branching fraction f…
Recently, the CDF collaboration reports an anomaly in dijet mass distribution in association with a lepton and missing energy. We discuss a possibility that the origin of the lepton and missing energy comes not from a W boson but a new boson particle, which is also responsible for the dijet mass peak. We show that such a situation can be realized in the framework of the minimal supersymmetric standard model and the dijet anomaly can be explained.
We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of $\sqrt{s}=1.96$ TeV proton-antiproton collisions corresponding to 9.1 fb$^{-1}$ of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering photon transverse momentum between 30 and 300 GeV, photon rapidities $|y^γ|<1.0$, heavy-quark-jet transverse momentum $p_{T}^{jet}>20$ GeV, and jet rapidities $|y^{jet}|<1.5$. The results are compared with sev…
We propose to add high precision track detectors 55m downstream on both (E&W) sides of CDF, to measure high Feynman-x protons and antiprotons in association with central states. A primary motivation is to search for the Higgs boson, and if it is seen to measure its mass precisely. The track detectors will be silicon strip telescopes backed up by high resolution time-of-flight counters. The addition of these small detectors effectively converts the Tevatron into a gluon-gluon collider with sqrt{s} from 0 to ~ 200 GeV. This experiment will also measure millions/year clean high-|t| elastic scatte…
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.
Recent results of searches for new physics in top events at the Tevatron are presented. In case of CDF three searches are discussed using 6.0 to 8.7 fb^{-1} of data, with the latter being the final CDF data sample available for this kind of analysis. CDF carried out a search for Top + jet resonance production, dark matter production in association with single top and boosted tops. No signs of new physics are observed and instead upper limits are derived. DØ used 5.3 fb^{-1} of data and searched for a narrow resonance in ttbar production and a time dependent ttbar cross section, which would rev…
We present a search for the standard model Higgs boson produced with a Z boson in 4.1 fb^-1 of data collected with the CDF II detector at the Tevatron. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electrons or muons, we set 95% credibility level upper limits on the ZH production cross section times the H -> b bbar branching ratio. Improved analysis methods enhance signal sensitivity by 20% relative to previous searches beyond the gain due to the larger data sample. At a Higgs boson mass of 115 GeV/c^2 we set a limit of 5.9 times the standard …
We report a new search for dark matter in a data sample of an integrated luminosity of 7.7 fb$^{-1}$ of Tevatron $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV, collected by the CDF II detector. We search for production of a dark matter candidate, $D$, in association with a single top quark. We consider the hadronic decay mode of the top quark exclusively, yielding a final state of three jets with missing transverse energy. The data are consistent with the standard model; we thus set 95% confidence level upper limits on the cross section of the process $p\bar{p}\rightarrow t+D$ as a function o…
We present a method for improving the $b$-jet energy resolution in order to improve the signal sensitivity in searches for particles decaying to a $b$ quark and anti-$b$ quark. A correction function is computed for individual jets, which combines information from the secondary vertex tagger, the offline tracking and standard calorimeter-based jet-energy reconstruction algorithm in order to provide a more accurate measurement of the true $b$-quark energy. We apply the correction to Monte-Carlo-simulated jets in the process $WH \rightarrow \ell νb\bar b$ and find an improvement in both the mean …
Vector boson production in association with jets is an important process to test perturbative quantum chromodynamics and also a background process in top quark analyses. Measurements on vector boson production in association with light and heavy flavour jets are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at LHC. Techniques applied in top quark analyses to estimate the vector boson+jets background are also discussed.
We present the first measurement of the production cross section of a W boson with a single charm quark (c) in p-pbar collisions at sqrt(s)=1.96 TeV, using soft muon tagging of c jets. In a data sample of ~1.8 fb-1, recorded with the CDF II detector at the Fermilab Tevatron, we select events with W+1 or 2 jets. We use the charge correlation between the W and the muon from the semileptonic decay of a charm hadron to extract the Wc signal. We measure sigma_{Wc}(p_{Tc}>20 GeV/c, |η_c|<1.5)\times BR(W->\ellν) = 9.8+/-3.2 pb, in agreement with theoretical expectations.
Latest results are presented in the search for low mass standard model Higgs production in association with a $W$ boson, based on large luminosity data samples collected at the CDF and D0 Experiments at the Fermilab Tevatron $p\bar{p}$ collider. The selection of event samples containing an isolated lepton, an imbalance in transverse energy in the events, and either one or two reconstructed jets consistent with having evolved from a $b$-quark, provides statistically independent data samples to search for $q\bar{q}\rightarrow WH$ candidates. Expected and observed upper limits are derived for the…
A search for particles with the same mass and couplings as those of the standard model Higgs boson but different spin and parity quantum numbers is presented. We test two specific non-standard Higgs boson hypotheses: a pseudoscalar Higgs boson with spin-parity $J^P$ = $0^-$ and a graviton-like Higgs boson with $J^P$ = $2^+$, assuming for both a mass of 125 GeV/$c^2$. We search for these exotic states produced in association with a vector boson and decaying into a bottom-antibottom quark pair. The vector boson is reconstructed through its decay into an electron or muon pair, or an electron or m…
The cross section of the $t\bar{t}Z$~and $t\bar{t}W$~processes are measured in a simultaneous fit using 36.1 $\text{fb}^{-1}$ of of proton--proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV recorded by the ATLAS experiment at the LHC. In addition, a fit is performed in the 4$\ell$ channel only, resulting in a cross section of $σ_{t\bar{t}Z} = 1.07 \pm 0.26 \,\text{pb}$. This result is consistent with the combined fit and agrees with the prediction by the Standard Model.
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…
The top quark, discovered in 1995 by the CDF and D0 collaborations at the Tevatron collider at Fermilab, is the heaviest known elementary particle today. Due to its high mass and short lifetime, the top quark plays a special role in searching for physics beyond the Standard Model. In this article, recent results of searches for new physics in the top sector, performed by CDF and D0, are presented. In particular, we discuss the search for ttbar resonances, for tj resonances, the search for heavy fourth generation quarks, for dark matter produced in association with single tops, the study of ano…
We present a search for neutral Higgs bosons decaying into b-bbar, produced in association with b quarks in p-pbar collisions. This process could be observable in supersymmetric models with high values of tan(beta). The event sample corresponds to 2.6/fb of integrated luminosity collected with the CDF II detector at the Fermilab Tevatron collider. We search for an enhancement in the mass of the two lead jets in events with three jets identified as coming from b quarks using a displaced vertex algorithm. A data-driven procedure is used to estimate the dijet mass spectrum of the non-resonant mul…
Recent measurements of the top quark mass in the dilepton ($t\bar{t}\to \bar{b}\ell^{-}\bar{ν_{\ell}}b \ell^{'+}ν^{'}_{\ell}$) and alljets ($t\bar{t}\to b\bar{b}q\bar{q}'q'\bar{q}$) decay channels from the CDF and D0 collaborations are presented. These decay channels provide unique challenges from the lepton+jets decay channel. Results utilizing up to 2.8 fb$^{-1}$ of $p\bar{p}$ collider data from the Fermilab Tevatron are discussed.
A measurement of the Higgs boson production cross sections via associated $WH$ and $ZH$ production using $H \rightarrow WW^{\ast} \rightarrow \ellν\ellν$ decays, where $\ell$ stands for either an electron or a muon, is presented. Results for combined $WH$ and $ZH$ production are also presented. The analysis uses events produced in proton-proton collisions collected with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The data correspond to an integrated luminosity of 36.1 fb$ ^{-1}$ recorded at a centre-of-mass energy of 13 TeV. The products of the $H \rightarrow WW^{\ast}$ b…
We present a detailed examination of the heavy flavor content of the $W $ + jet data sample collected with the CDF detector during the 1992-1995 collider run at the Fermilab Tevatron. Jets containing heavy flavor quarks are selected via the identification of secondary vertices or semileptonic decays of $b$ and $c$ quarks. There is generally good agreement between the rates of secondary vertices and soft leptons in the data and in the standard model simulation including single and pair production of top quarks. An exception is the number of events in which a single jet has both a soft lepton an…
We combine searches by the CDF and D0 Collaborations for the associated production of a Higgs boson with a W or Z boson and subsequent decay of the Higgs boson to a bottom-antibottom quark pair. The data, originating from Fermilab Tevatron p-pbar collisions at sqrt{s}=1.96 TeV, correspond to integrated luminosities of up to 9.7 fb^-1. The searches are conducted for a Higgs boson with mass in the range 100-150 GeV/c^2. We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 120 and 135 GeV/c^2. The largest local si…
We present a measurement of the cross section for W-boson production in association with jets in pbar-p collisions at sqrt(s)=1.96 TeV. The analysis uses a data sample corresponding to an integrated luminosity of 320 pb^-1 collected with the CDF II detector. W bosons are identified in their electron decay channel and jets are reconstructed using a cone algorithm. For each W+>= n-jet sample (n= 1 - 4) we measure dsigma(ppbar =>W+>=n-jet)/dE_T^(nth-jet) x BR(W => e nu) with respect to the transverse energy E_T of the n^th-highest E_T jet above 20 GeV, and the total cross section sigma(ppbar =>W+…
Motivated by recent anomalous CDF data on $Wjj$ events, we study a possible explanation within the framework of the two-Higgs doublet model. We find that a charged Higgs boson of mass $\sim$ 140 GeV with appropriate couplings can account for the observed excess. In addition, we consider the flavor-changing neutral current effects induced at loop level by the charged Higgs boson on the $B$ meson system to further constrain the model. Our study shows that the like-sign charge asymmetry $A_{s\ell}^b$ can be of ${\cal O}(10^{-3})$ in this scenario.
We present a search for standard model Higgs boson production in association with a W boson in proton-antiproton collisions at a center of mass energy of 1.96 TeV. The search employs data collected with the CDF II detector that correspond to an integrated luminosity of approximately 1.9 inverse fb. We select events consistent with a signature of a single charged lepton, missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with a secondary vertex tagging method, a jet probability tagging method, and a neural network filter. We use kinematic information in …
This Letter reports measurements of differential cross sections for the production of two Z bosons in association with jets in proton-proton collisions at $\sqrt{s} =$ 8 and 13 TeV. The analysis is based on data samples collected at the LHC with the CMS detector, corresponding to integrated luminosities of 19.7 and 35.9 fb$^{-1}$ at 8 and 13 TeV, respectively. The measurements are performed in the leptonic decay modes ZZ $\to\ell^+ \ell^- \ell'^+ \ell'^-$, where $\ell,\ell' =$ e, $μ$. The differential cross sections as a function of the jet multiplicity, the transverse momentum $p_\mathrm{T}$,…
Measurements of production cross sections of WZ and same-sign WW boson pairs in association with two jets in proton-proton collisions at $\sqrt{s} =$ 13 TeV at the LHC are reported. The data sample corresponds to an integrated luminosity of 137 fb$^{-1}$, collected with the CMS detector during 2016-2018. The measurements are performed in the leptonic decay modes W$^\pm$Z $\to$ $\ell^\pmν\ell'^\pm\ell'^\mp$ and WW $\to$ $\ell^\pmν\ell'^\pmν$, where $\ell, \ell' = $ e, $μ$. Differential fiducial cross sections as functions of the invariant masses of the jet and charged lepton pairs, as well as o…
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…
Cross section predictions of W and Z bosons in association with jets (up to 6 jets, $W\to\ell^{\pm}ν$ and $Z\to\ell^{\pm}$ where $\ell^{\pm}$=$e^{\pm}$ or $μ^{\pm}$) in proton-proton collisions at $\sqrt{s}$=14 TeV is performed using Alpgen MC generator with CTEQ6L1 leading order parton distribution function. In addition, W and Z boson cross sections are obtained up to next to next to leading order (NNLO) QCD corrections using MCFM MC generator. To validate the predictions, a detailed comparison of NNLO QCD calculations with 8 TeV CMS results for total cross section is performed and a fiducial…
A search for the standard model Higgs boson produced in association with a top-quark pair is presented using data samples corresponding to an integrated luminosity of 5.0 inverse femtobarns (5.1 inverse femtobarns) collected in pp collisions at the center-of-mass energy of 7 TeV (8 TeV). Events are considered where the top-quark pair decays to either one lepton+jets (t tbar to ell nu q q' b bbar) or dileptons (t tbar to ell(+) nu ell(-) nu b bbar), ell being an electron or a muon. The search is optimized for the decay mode H to b bbar. The largest background to the t tbar H signal is top-quark…
Prompt photon production results by the CDF and D\OCollaborations in the Tevatron Run II at a center of mass energy of $\sqrt{s}$=1.96 TeV are presented. Cross sections for central isolated photons, photon+jet production and photons produced in association with a heavy flavor quark are reported. The measurements are compared to Next-to-Leading order perturbative QCD predictions.
The first observation of the production of a $W$ boson with a single charm quark ($c$) jet in $p\bar{p}$ collisions at $\sqrt{s}=1.96 {\rm TeV}$ is reported. The analysis uses data corresponding to 4.3 fb$^{-1}$, recorded with the CDF II detector at the Fermilab Tevatron. Charm quark candidates are selected through the identification of an electron or muon from charm-hadron semileptonic decay within a hadronic jet, and a $Wc$ signal is observed with a significance of 5.7 standard deviations. The production cross section $σ_{Wc}(p_{Tc}>20 {\rm GeV}/c, |η_c|<1.5)\times B(W\rightarrow \ellν)$ is …
