The Upsilon production cross section in proton-proton collisions at sqrt(s) = 7 TeV is measured using a data sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 3.1 +/- 0.3 inverse picobarns. Integrated over the rapidity range |y|<2, we find the product of the Upsilon(1S) production cross section and branching fraction to dimuons to be sigma(pp to Upsilon(1S) X) B(Upsilon(1S) to mu+ mu-) = 7.37 +/- 0.13^{+0.61}_{-0.42}\pm 0.81 nb, where the first uncertainty is statistical, the second is systematic, and the third is associated with the estimation of the integrated luminosity of the data sample. This cross section is obtained assuming unpolarized Upsilon(1S) production. If the Upsilon(1S) production polarization is fully transverse or fully longitudinal the cross section changes by about 20%. We also report the measurement of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) differential cross sections as a function of transverse momentum and rapidity.
Using the Belle detector operating at the KEKB e+e- storage ring, we have measured the mean multiplicity and the momentum spectrum of neutral pions from the decays of the Upsilon(4S) resonance. We measure a mean of 4.70 +/- 0.04 +/- 0.22 neutral pions per Upsilon(4S) decay.
We present measurements of the inclusive production cross sections of the Upsilon(1S) bottomonium state in ppbar collisions at sqrt(s) = 1.96 TeV. Using the Upsilon(1S) to mu+mu- decay mode for a data sample of 159 +- 10 pb^-1 collected by the D0 detector at the Fermilab Tevatron collider, we determine the differential cross sections as a function of the Upsilon(1S) transverse momentum for three ranges of the Upsilon(1S) rapidity: 0 < |y| < 0.6, 0.6 < |y| < 1.2, and 1.2 < |y| < 1.8.
We have searched for the bottomonium eta_b(1S) via the hindered magnetic dipole (M1) photon transition Upsilon(3S) -> gamma eta_b(1S). No evidence for such a transition is found in the data sample of 4.7 x 10^6 Upsilon(3S)'s collected with the CLEO-III detector. We set upper limits on the branching ratio from 9.30 to 9.43 GeV/c^2 of eta_b(1S) masses. These upper limits rule out many previously published phenomenological estimates of the rate for this transition.
Using the CLEO II detector at CESR, we measure the eta' - gluon - gluon form-factor in Y(1S) decays. This form-factor especially at large eta' energies may provide an explanation of the large rate for B -> Xs eta'. Our data do not support a large anomalous coupling at higher q^2 and thus the large eta' rate remains a mystery, possibly requiring a non-Standard Model explanation.
We describe a new analysis of Upsilon(nS) to mu+mu- decays collected in proton anti-proton collisions with the CDF II detector at the Fermilab Tevatron. This analysis measures the angular distributions of the final state muons in the Upsilon rest frame, providing new information about Upsilon production polarization. We find the angular distributions to be nearly isotropic up to Upsilon transverse momentum of 40 GeV/c, consistent with previous measurements by CDF, but inconsistent with results obtained by the D0 experiment. The results are compared with recent NLO calculations based on color-s…
Differential cross sections as a function of transverse momentum pt are presented for the production of Y(nS) (n = 1, 2, 3) states decaying into a pair of muons. Data corresponding to an integrated luminosity of 4.9 inverse femtobarns in pp collisions at sqrt(s) = 7 TeV were collected with the CMS detector at the LHC. The analysis selects events with dimuon rapidity abs(y) < 1.2 and dimuon transverse momentum in the range 10 < pt < 100 GeV. The measurements show a transition from an exponential to a power-law behavior at pt ~ 20 GeV for the three Y states. Above that transition, the Y spectrum…
Pair production of Upsilon(1S) mesons is observed at the LHC in proton-proton collisions at sqrt(s) = 8 TeV by the CMS experiment in a data sample corresponding to an integrated luminosity of 20.7 inverse femtobarns. Both Upsilon(1S) candidates are fully reconstructed via their decays to mu+ mu-. The fiducial acceptance region is defined by an absolute Upsilon(1S) rapidity smaller than 2.0. The fiducial cross section for the production of Upsilon(1S) pairs, assuming that both mesons decay isotropically, is measured to be 68.8 +/- 12.7 (stat) +/- 7.4 (syst) +/- 2.8 (B) pb, where the third uncer…
The Upsilon(1S), Upsilon(2S), and Upsilon(3S) production cross sections are measured using a data sample corresponding to an integrated luminosity of 35.8 +/-1.4 inverse picobarns of proton-proton collisions at sqrt(s) = 7 TeV, collected with the CMS detector at the LHC. The Upsilon resonances are identified through their decays to dimuons. Integrated over the Upsilon transverse momentum range pt[Upsilon] < 50 GeV and rapidity range abs(y[Upsilon]) < 2.4, and assuming unpolarized Upsilon production, the products of the Upsilon production cross sections and dimuon branching fractions are sigma(…
We discuss in detail the photon spectrum of radiative Upsilon 1S decays taking into account a number of results that have recently appeared in the literature. In particular, we show how to consistently combine expressions which are valid in the upper end-point region, where NRQCD factorization breaks down, with those of the central region, where NRQCD factorization holds. An excellent description of data is achieved, but theoretical errors are large.
Using data corresponding to an integrated luminosity of 1.3 fb^-1, we observe a narrow mass state decaying into Upsilon(1S)+gamma, where the Upsilon(1S) meson is detected by its decay into a pair of oppositely charged muons, and the photon is identified through its conversion into an electron-positron pair. The significance of this observation is 5.6 standard deviations. The mass of the state is centered at 10.551 \pm 0.014 (stat.) \pm 0.017 (syst.) GeV/c^2, which is consistent with that of the state recently observed by the ATLAS Collaboration.
The results of a search for the bottomonium counterpart, denoted as Xb, of the exotic charmonium state X(3872) is presented. The analysis is based on a sample of pp collisions at sqrt(s) = 8 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 20.7 inverse femtobarns. The search looks for the exclusive decay channel Xb to Upsilon(1S) pi+ pi- followed by Upsilon(1S) to mu+ mu-. No evidence for an Xb signal is observed. Upper limits are set at the 95% confidence level on the ratio of the inclusive production cross sections times the branching fractions to …
Using 1.8 fb-1 of pp collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the Large Hadron Collider, we present measurements of the production cross sections of Upsilon(1S,2S,3S) mesons. Upsilon mesons are reconstructed using the di-muon decay mode. Total production cross sections for p_T<70 GeV and in the rapidity interval |Upsilon|<2.25 are measured to be 8.01+-0.02+-0.36+-0.31 nb, 2.05+-0.01+-0.12+-0.08 nb, 0.92+-0.01+-0.07+-0.04 nb respectively, with uncertainties separated into statistical, systematic, and luminosity measurement effects. In addition, differenti…
BaBar experiment scan around the Upsilon(4S) resonance and measure its mass and full width. They also measure Br(Upsilon(4S) -> B0 B0b) = 0.486 +/- 0.010 +/- 0.009 from 81.7 fb-1 Upsilon(4S) data. CLEO collaboration took about 0.42 fb-1 Upsilon(5S) data. They search for B_s in both inclusive and exclusive modes and find evidence for B_s production at the Υ(5S) and Br(Upsilon(5S) -> B_s^(*) B_s^(*)b) = (21 +/- 3 +/- 9)%.
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…
A measurement of the cross-section for Upsilon(1S) -> mu+mu- production in proton-proton collisions at centre of mass energy of 7 TeV is presented. The cross-section is measured as a function of the Upsilon(1S) transverse momentum in two bins of rapidity, |y(Upsilon1S)| < 1.2 and 1.2 < |y(Upsilon1S)| < 2.4. The measurement requires that both muons have transverse momentum pT(mu) > 4 GeV and pseudorapidity |eta(mu)| < 2.5 in order to reduce theoretical uncertainties on the acceptance, which depend on the poorly known polarization. The results are based on an integrated luminosity of 1.13 pb-1, …
Motivated by concerns regarding possible two-body contributions to the recently-measured inclusive Upsilon(nS)->gamma+X (n=1, 2, 3) direct photon spectra, we report on a new study of exclusive radiative decays of these narrow Upsilon(nS) resonances into two-body final states R+gamma, with R a narrow resonant hadronic state decaying into four or more charged particles. Such two-body processes are not explicitly addressed in the extant theoretical frameworks used to calculate the inclusive direct photon spectra, and must also be explicitly inserted into Monte Carlo simulations. Using data collec…
The NLO QCD corrections to Upsilon production via S-wave color-octet states Upsilon(^1S_0^8,^3S_1^8) at the Tevatron and LHC is calculated. The K factors of total cross section (ratio of NLO to LO) are 1.313 and 1.379 for Upsilon(^1S_0^8) and Upsilon(^3S_1^8) at the Tevatron, while at the LHC they are 1.044 and 1.182, respectively. By fitting the experimental data from the D0, the matrix elements for S-wave color-octet states are obtained. And new predictions for Upsilon production are presented. The prediction for the polarization of inclusive Upsilon contains large uncertainty rising from th…
A preliminary result on the study of the inclusive electron spectrum in B -> X_u e nu decays above the kinematic limit for the dominant B -> X_c e nu transitions is presented. This study is performed at the PEP-II asymmetric B Factory, where B meson pairs are produced in the decay of the Upsilon(4S) resonance. For the electron momentum range of 2.3 - 2.6 GeV/c in the Upsilon(4S) rest frame, the partial branching ratio is measured to be Delta B(B -> X_u e nu)=(0.152+-0.014+-0.014) 10^{-3}.
We report a precise determination of the B0-B0bar mixing parameter Delta-m_d based on the time evolution of same-sign and opposite-sign dilepton yields in Upsilon(4S) decays. Data were collected with the Belle detector at KEKB. Using data samples of 29.4 1/fb recorded at the Upsilon(4S) resonance and 3.0 1/fb recorded at an energy 60MeV below the resonance, we measure Delta m_d = (0.503 +- 0.008(stat) +- 0.010(sys)) 1/ps. From the same analysis, we also measure the ratio of charged and neutral B meson production at the Upsilon(4S), f+/f0 = 1.01 +- 0.03(stat) +- 0.09(sys), and CPT violation par…
A measurement of the production cross section ratio sigma(chi[b2](1P)) / sigma( chi[b1](1P)) is presented. The chi[b1](1P) and chi[b2](1P) bottomonium states, promptly produced in pp collisions at sqrt(s) = 8 TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays chi[b1,2](1P) to Upsilon(1S) + gamma. The emitted photons are measured through their conversion to electron-positron pairs, whose reconstruction allows the two states to be resolved. The Upsilon(1S) is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of …
We use data collected by the CLEO III detector at CESR on the Upsilon(5S) resonance to measure the inclusive yield of Ds mesons. Comparing with data taken on the Upsilon(4S), which decays into lighter B mesons, we make a model dependent estimate of the ratio of Bs(*)anti-Bs(*) to the total b anti-b quark pair production at the Upsilon(5S) energy of (16.0+/-2.6+/-5.8)%.
The exclusive photoproduction of $Υ$(1S), $Υ$(2S) and $Υ$(3S) mesons is studied in their leptonic ($μ^{+}μ^{-}$) decay modes, in ultraperipheral pPb collisions at $\sqrt{s_{NN}} = 5.02$ TeV. The data was recorded by the CMS experiment corresponding to an integrated luminosity of $32.6$ nb$^{-1}$. The differential cross-section for $Υ$(n) states (n=1,2,3), has been measured as a function of transverse momentum squared $p_{T}^{2}$, and rapidity $y$. The $Υ$(1S) photoproduction cross-section is extracted in the region $|y|<2.2$ as a function of the photon-proton centre-of-mass energies $W_{γp}$, …
Based on nonrelativistic QCD factorization scheme, we present the first complete next-to-leading order study on the yield and polarization of Upsilon(1S,2S,3S) hadroproduction. By using the color-octet long-distance matrix elements obtained from fits of the experimental measurements on Upsilon yield and polarization at the Tevatron and LHC, our results can explain the measurements on the yield very well, and for the polarizations of Upsilon(1S,2S,3S), they are in (good, good, bad) agreement with recent CMS measurement, but still have some distance from the CDF measurement.
CDF has obtained new results on quarkonium production in p\bar{p} collisions at \sqrt{s} = 1.8 TeV. We report on measurements of Upsilon meson production, Upsilon(1S) production from Chi_b feeddown, and the production polarization of Upsilon(1S), J/Psi and Psi(2S) mesons.
We present recent results on heavy flavour production at Tevatron Run II for typically ~1/fb of analysed proton-antiproton data at a c.m. energy of 1.96 TeV. This includes results on single and correlated open charm and bottom cross sections, charm pair production kinematics, J/psi, psi(2S) and chi cross sections and polarisation measurements in J/psi, psi(2S), Upsilon(1S), and Upsilon(2S).
We present measurements of the total production rates and momentum distributions of the charmed baryon $Λ_c^+$ in $e^+e^- \to$ hadrons at a center-of-mass energy of 10.54 GeV and in $Υ(4S)$ decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in $e^+e^- \to c\bar{c}$ events, allowing direct studies of $c$-quark fragmentation. We measure a momentum distribution for $Λ_c^+$ baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely.…
We study inclusive di-pion decays using a sample of 108 x 10^6 Upsilon(3S) events recorded with the BABAR detector. We search for the decay mode Upsilon(3S) --> pi+ pi- h_b(1P) and find no evidence for the bottomonium spin-singlet state h_b(1P) in the invariant mass distribution recoiling against the pi+ pi- system. Assuming the h_b(1P) mass to be 9.900 GeV/c^2, we measure the upper limit on the branching fraction B[Upsilon(3S) --> pi+ pi- h_b(1P)] < 1.2 x 10^{-4}, at 90% confidence level. We also investigate the chi_{bJ}(2P) --> pi+ pi- chi_{bJ}(1P), Upsilon(3S) --> pi+ pi- Upsilon(2S), and U…
We revisit inclusive J/psi and Upsilon photoproduction at lepton-hadron colliders, namely in the limit when the exchanged photon is quasi real. Our computation includes the next-to-leading-order (NLO) alpha_s corrections to the leading-order contributions in v. Similarly to the case of NLO charmonium-hadroproduction processes, the resulting cross sections obtained in the MS-bar factorisation scheme are sometimes found to be negative. We show that the scale-fixing criteria which we derived in a previous study of eta(c) production successfully solves this problem from the EicC all the way up to …
Heavy quark production probes QCD at the interface of the perturbative and non-perturbative regimes. Studying the production of heavy quarks is an important test of models in both regimes. In this article, recent results on beauty and charm production from the CDF and D0 experiments at the Tevatron are reported. These include measurements of correlated b-bbar production, the psi(2S) production cross section, and Upsilon(1S) and Upsilon(2S) polarization.
We present spectra of prompt electrons from decays of neutral and charged B mesons. The results are based on 140 /fb of data collected by the Belle detector on the Upsilon(4S) resonance at the KEKB e+e- asymmetric collider. We tag Upsilon(4S) -> B \bar{B} events by reconstructing a B meson in one of several hadronic decay modes; the semileptonic decay of the other B meson is inferred from the presence of an identified electron. We obtain for charged and neutral B mesons the partial rates of semileptonic decay, to electrons with momentum greater than 0.6 GeV/c in the B rest frame, and their rat…
Motivated by concerns regarding possible two-body contributions to the recently-measured inclusive $Υ$(nS)$\toγ+X$ direct photon spectrum, we report on a preliminary new study of exclusive radiative decays of the $Υ$ resonances into two-body final states ${\cal R}γ$, with ${\cal R}$ some resonant hadronic state decaying into four or more charged particles. Such two-body processes are not explicitly addressed in the extant theoretical frameworks used to calculate the inclusive direct photon spectrum. Using data collected from the CLEO III detector at the Cornell Electron Storage Ring, we presen…
The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. Th…
Using data taken with the CLEO III detector at the Cornell Electron Storage Ring, we have investigated the direct photon spectrum in the decays Upsilon(1S) -> gggamma, Upsilon(2S) -> gggamma, Upsilon}(3S) -> gggamma. The latter two of these are first measurements. Our analysis procedures differ from previous ones in the following ways: a) background estimates (primarily from pi^0 decays are based on isospin symmetry rather than a determination of the pi^0 spectrum, which permits measurement of the Upsilon(2S) and Upsilon(3S) direct photon spectra without explicit corrections for pi^0 backgroun…
Based on the nonrelativistic QCD (NRQCD) factorization formalism, we investigate inclusive productions of two spin-triplet S-wave quarkonia pp->2J/psi+X, 2Upsilon+X, and J/psi+Upsilon+X at the CERN Large Hadron Collider. The total production rates integrated over the rapidity (y) and transverse-momentum (p_T) ranges |y|<2.4 and p_T<50 GGeV are predicted to be sigma[pp->2J/psi+X] = 22 (35) nb, sigma[pp->2Upsilon+X] = 24 (49) pb, and sigma[pp->J/psi+Upsilon+X] = 7 (13) pb at the center-of-momentum energy sqrt{s} = 7 (14) TeV. In order to provide predictions that can be useful in both small- and …
We analyze the end-point region of the photon spectrum in semi-inclusive radiative decays of very heavy quarkonium (m alpha_s^2 >> Lambda_QCD). The S- and P-wave octet shape functions are calculated. When they are included in the analysis of the photon spectrum of the Upsilon (1S) system the agreement with data becomes excellent.
We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral B's through a partial reconstruction of B0 --> D*- l+ nu. This spectrum, measured with 2.38 fb**-1 of data collected at the Upsilon(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all Upsilon(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B0 and B+ semileptonic branching fractions, b0 and b+, their ratio, and t…
We have measured the branching fraction of the inclusive radiative B meson decay B --> X(s) gamma to be Br(B->X(s)gamma)=(3.36 +/- 0.53(stat) +/- 0.42(sys) +0.50-0.54(th)) x 10^{-4}. The result is based on a sample of 6.07 x 10^6 BBbar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e^+e^- storage ring.
Measurements of heavy flavor production in pp collisions at sqrt(s) = 7.0 TeV recorded at the CMS experiment are presented. Double differential cross sections with respect to transverse momentum and rapidity are shown for J/Psi and Upsilon(1S), Upsilon(2S), and Upsilon(3S). The inclusive open beauty rate is measured with two different techniques, including a study of the angular correlations between b jets in events with two identified b jets. Lastly, the B+, B0, and B0s production rates are measured from the reconstruction of exclusive final states.
Results are presented for the inclusive jet cross section versus jet transverse energy in proton-antiproton collisions at center of mass energy 1.8 TeV as measured by the CDF and D0 detectors at Fermilab's Tevatron collider. The data are compared to next-to-leading order QCD predictions using different input parton distribution functions. The ratio of inclusive jet cross sections at center of mass energy 0.63 TeV and center of mass energy 1.8 TeV, versus jet x_T, is also presented and compared to QCD predictions.
The systematic uncertainties of the measurements of the Inclusive Jet Cross Section at the Tevatron and their effect on the chi^2 comparisons between data and theoretical predictions are discussed.
A largely model-independent measurement of the inclusive electron momentum spectrum and branching fraction for semileptonic decays of B mesons is presented based on data recorded at the Upsilon(4S) resonance with the BABAR detector. Backgrounds from secondary charm decays are separated from prompt B decays using charge and angular correlations between the electron from one B meson and a high momentum electron tag from the second B meson. The resulting branching fraction is BR(B -> X e nu) = (10.87 +-0.18(stat)+-0.30(syst))%. Based on this measurement we determine the CKM matrix element |V_cb|.
Results of exclusive photoproduction of Upsilon states in Ultraperipheral collisions (UPC) of protons and ions with the CMS experiment are presented, which provides a clean probe of the gluon distribution at small values of parton fractional momenta $x \approx 10^{-2} 10^{4}$ at central rapidities (|y| $< 2.5$). The three Upsilon states (1S, 2S, 3S) are measured in the dimuon decay channel along with the photon-photon decaying to dimuon QED continuum at $\sqrt{s_{NN}}=5.02$~TeV for integrated luminosity of $L_{int} = 35$ nb$^{-1}$. The total Upsilon photoproduction cross sections at different …
A measurement is presented of the ratio of the inclusive 3-jet cross section to the inclusive 2-jet cross section as a function of the average transverse momentum, <pT[1,2]>, of the two leading jets in the event. The data sample was collected during 2011 at a proton-proton centre-of-mass energy of 7 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 5.0 inverse femtobarns. The strong coupling constant at the scale of the Z boson mass is determined to be alphaS[MZ] = 0.1148 +/- 0.0014 (exp.) +/- 0.0018 (PDF) +/- 0.0050 (theory), by comparing the ratio in the rang…
Using 420 pb^-1 of data collected on the Upsilon(5S) resonance with the CLEO III detector, we reconstruct B mesons in 25 exclusive decay channels to measure or set upper limits on the decay rate of Upsilon(5S) into B meson final states. We measure the inclusive B cross-section to be sigma(Y(5S)-->BB(X))=(0.176+-0.030+-0.016) nb and make the first measurements of the production rates of sigma(Y(5S)-->B*B*)=(0.131+-0.025+-0.014) nb and sigma(Y(5S)-->BB*)=(0.043+-0.016+-0.006) nb, respectively. We set 90% confidence level limits of sigma(Y(5S)-->B B-bar)<0.038 nb, sigma(Y(5S)-->B(*)B(*)(pi))<0.05…
The latest results of the ATLAS experiment for the production of a top-quark pair in association with a photon using proton-proton collision data from the LHC at a centre-of-mass energy of 13 TeV are summarised here. This includes inclusive and differential cross-sections measurements performed in single-lepton and dilepton final states in a fiducial volume corresponding to the experimental acceptance.
A measurement of the lepton charge asymmetry in inclusive pp to WX production at sqrt(s)= 7 TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. This high precision measurement of the lepton charge asymmetry, performed in both the W to e nu and W to mu nu channels, provides new insights into parton distribution functions.
Measurements performed by the CMS experiment of the cross section for inclusive $b$-quark production in proton-proton collisions at $\sqrt{s}= 7$ TeV are presented. The measurements are based on different methods, such as inclusive jet measurements with secondary vertex tagging or selecting a sample of events containing jets and at least one muon, where the transverse momentum of the muon with respect to the closest jet axis discriminates $b$-events from the background. The results are compared with predictions based on perturbative QCD calculations at leading and next-to-leading order.
We present the methods for an early measurement of the inclusive W->ev production cross section in pp collisions at sqrt(s)= 14 TeV. The methods are studied assuming 10 inverse picobarn integrated luminosity of the data and conditions of the Compact Muon Solenoid (CMS) detector at the early data taking period.
Measurements performed by the CMS experiment of the cross section for inclusive b-quark production in proton-proton collisions at sqrt(s) = 7 TeV are presented. The measurements are based on different methods, such as inclusive jet measurements with secondary vertex tagging or selecting a sample of events containing jets and at least one muon, where the transverse momentum of the muon with respect to the closest jet axis discriminates b events from the background. The results are compared with predictions based on perturbative QCD calculations at leading and next-to-leading order.
The inclusive jet cross-section has been measured in proton-proton collisions at sqrt(s)=2.76 TeV in a dataset corresponding to an integrated luminosity of 0.20pb-1 collected with the ATLAS detector at the Large Hadron Collider in 2011. Jets are identified using the anti-kt algorithm with two radius parameters of 0.4 and 0.6. The inclusive jet double-differential cross-section is presented as a function of the jet transverse momentum pT and jet rapidity y, covering a range of 20 <= pT < 430 GeV and |y| < 4.4. The ratio of the cross-section to the inclusive jet cross-section measurement at sqrt…
We have made a precise measurement of the central inclusive jet cross section at sqrt(s) = 1.8 TeV. The measurement is based on an integrated luminosity of 92 pb-1 collected at the Fermilab Tevatron pbar-p Collider with the D-Zero detector. The cross section, reported as a function of jet transverse energy (ET >= 60 GeV) in the pseudorapidity interval |eta| <= 0.5, is in good agreement with predictions from next-to-leading order quantum chromodynamics.
Using Upsilon(2S) and Upsilon(3S) data collected with the CLEO III detector we have searched for decays of chi_bJ to final states with open charm. We fully reconstruct D0 mesons with p_D0 > 2.5 GeV/c in three decay modes (K-pi+, K-pi+pi0, and K-pi-pi+pi+) in coincidence with radiative transition photons that tag the production of one of the chi_bJ(nP) states. We obtain significant signals for the two J=1 states. Recent NRQCD calculations of chi_{bJ}(nP) --> c cbar X depend on one non-perturbative parameter per chi_bJ triplet. The extrapolation from the observed D0 X rate over a limited momentu…
We present a measurement of the inclusive jet cross section in ppbar interactions at sqrt{s}=1.96 TeV using 385 pb^{-1} of data collected with the CDF II detector at the Fermilab Tevatron. The results are obtained using an improved cone-based jet algorithm (Midpoint). The data cover the jet transverse momentum range from 61 to 620 GeV/c, extending the reach by almost 150 GeV/c compared with previous measurements at the Tevatron. The results are in good agreement with next-to-leading order perturbative QCD predictions using the CTEQ6.1M parton distribution functions.
Using 605/fb of data collected at the Upsilon(4S) resonance we present a measurement of the inclusive radiative B-meson decay channel, B to X_s gamma. For the lower photon energy thresholds of 1.7, 1.8, 1.9 and 2.0GeV, as defined in the rest frame of the B-meson, we measure the partial branching fraction and the mean and variance of the photon energy spectrum. At the 1.7GeV threshold we obtain the partial branching fraction BF(B to X_s gamma) = (3.45 +/- 0.15 +/- 0.40) x 10^-4, where the errors are statistical and systematic.
The inclusive spectrum of π^0 production has been measured in pp collisions at \sqrt{s} = 900 GeV and 7 TeV with the ALICE experiment. The preliminary results of these measurements are presented, and perspectives for π^0 measurements with heavy ions are discussed.
Recent measurements of the inclusive top pair production at the Tevatron and LHC collider in the electron/muon final states are discussed. Measurements at the Tevatron use up to 9.7 /fb of data, and at the LHC up to 4.9 /fb of data at $\sqrt{s}=7$ TeV and up to 20.3 /fb of data at $\sqrt{s}=8$ TeV. For the experiments at both colliders these corresponds to the full data sets at the given center-of-mass energies. Overall results are in agreement between the experiments at the Tevatron and between the experiments at the LHC. All measurements are in agreement with recent theory calculations at NN…
We present an inclusive search for strange pentaquark production in e+e- interactions at a center-of-mass energy of 10.58 GeV using 123 fb-1 of data collected with the BaBar detector. We look for the states that have been reported previously: the Theta+(1540), interpreted as a ududsbar state; and the Xi--(1860) and Xi0(1860), candidate dsdsubar and uss(uubar+ddbar) states, respectively. In addition we search for other members of the antidecuplet and corresponding octet to which these states are thought to belong. We find no evidence for the production of such states and set preliminary limits …
The inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the LHC using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 inverse picobarns. The measurement is made for jet transverse momenta in the range 18-1100 GeV and for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jet pT ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leading-order perturbative QCD predictions.
The central inclusive jet cross section has been measured using a successive-combination algorithm for reconstruction of jets. The measurement uses 87.3 pb^{-1} of data collected with the D0 detector at the Fermilab Tevatron ppbar Collider during 1994-1995. The cross section, reported as a function of transverse momentum (pT>60 GeV) in the central region of pseudorapidity (|η|<0.5), exhibits reasonable agreement with next-to-leading order QCD predictions, except at low pT where the agreement is marginal.
