Modeling missing transverse energy in V+jets at CERN LHC

I discuss a method to model the instrumental response of the CMS and ATLAS detectors at high transverse missing energies to dominant standard model V+jets backgrounds, where V is a Z, gamma or W, using multi-jet QCD events. The method is developed for new physics searches in early data at the Large Hadron Collider (LHC) with minimal recourse to simulation.Comment: Replaced with the published versio

Study of LHC Searches for a Lepton and Many Jets

Searches for new physics in high-multiplicity events with little or no missing energy are an important component of the LHC program, complementary to analyses that rely on missing energy. We consider the potential reach of searches for events with a lepton and six or more jets, and show they can provide increased sensitivity to many supersymmetric and exotic models that would not be detected through standard missing-energy analyses. Among these are supersymmetric models with gauge mediation, R-parity violation, and light hidden sectors. Moreover, ATLAS and CMS measurements suggest the primary background in this channel is from t-tbar, rather than W+jets or QCD, which reduces the complexity of background modeling necessary for such a search. We also comment on related searches where the lepton is replaced with another visible object, such as a Z boson.Comment: 23 pages, 12 figures, 1 tabl

Radiative Decays of the Upsilon(1S) to a Pair of Charged Hadrons

Using data obtained with the CLEO~III detector, running at the Cornell Electron Storage Ring (CESR), we report on a new study of exclusive radiative Upsilon(1S) decays into the final states gamma pi^+ pi^-, gamma K^+ K^-, and gamma p pbar.. We present branching ratio measurements for the decay modes Upsilon(1S) to gamma f_2(1270), Upsilon(1S) to gamma f_2'(1525), and Upsilon(1S) to gamma K^+K^-; helicity production ratios for f_2(1270) and f_2'(1525); upper limits for the decay Upsilon(1S) to gamma f_J(2200), with f_J(2220) to pi^+ pi^-, K^+ K^-, p pbar; and an upper limit for the decay Upsilon(1S) to gamma X(1860), with X(1860) to gamma p pbar.Comment: 17 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2005/, Submitted to PR

Improved Measurement of the Form Factors in the Decay Lambda_c^+ --> Lambda e^+ nu_e

Using the CLEO detector at the Cornell Electron Storage Ring, we have studied the distribution of kinematic variables in the decay Lambda_c^+ -> Lambda e^+ nu_e. By performing a four-dimensional maximum likelihood fit, we determine the form factor ratio, R = f_2/f_1 = -0.31 +/- 0.05(stat) +/- 0.04(syst), the pole mass, M_{pole} = (2.21 +/- 0.08(stat) +/- 0.14(syst)) GeV/c^2, and the decay asymmetry parameter of the Lambda_c, alpha_{Lambda_c} = -0.86 +/- 0.03(stat) +/- 0.02(syst), for = 0.67 (GeV/c^2)^2. We compare the angular distributions of the Lambda_c^+ and Lambda_c^- and find no evidence for CP-violation: A_{Lambda_c} = (alpha_{Lambda_c^+} + alpha_{Lambda_c^-})/ (alpha_{Lambda_c^+} - alpha_{Lambda_c^-}) = 0.00 +/- 0.03(stat) +/- 0.01(syst) +/- 0.02, where the third error is from the uncertainty in the world average of the CP-violating parameter, A_{Lambda}, for Lambda -> p pi^-.Comment: 8 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PR

Observation of the Hadronic Transitions Chi_{b 1,2}(2P) -> omega Upsilon(1S)

The CLEO Collaboration has observed the first hadronic transition among bottomonium (b bbar) states other than the dipion transitions among vector states, Upsilon(nS) -> pi pi Upsilon(mS). In our study of Upsilon(3S) decays, we find a significant signal for Upsilon(3S) -> gamma omega Upsilon(1S) that is consistent with radiative decays Upsilon(3S) -> gamma chi_{b 1,2}(2P), followed by chi_{b 1,2} -> omega Upsilon(1S). The branching ratios we obtain are Br(chi_{b1} -> omega Upsilon(1S) = 1.63 (+0.35 -0.31) (+0.16 -0.15) % and Br(chi_{b2} -> omega Upsilon(1S) = 1.10 (+0.32 -0.28) (+0.11 - 0.10)%, in which the first error is statistical and the second is systematic.Comment: submitted to XXI Intern'l Symp on Lepton and Photon Interact'ns at High Energies, August 2003, Fermila

Observation of psi(3770)--> pi pi J/psi and Measurement of Gamma_{ee}[psi(2S)]

We observe signals for the decays psi(3770)--> X J/psi from data acquired with the CLEO detector operating at the CESR e^+e^- collider with sqrt{s}=3773 MeV. We measure the following branching fractions B(psi(3770)--> XJ/psi) and significances: (189 +- 20 +- 20) x 10^-5 (11.6sigma) for X=pi^+pi^-, (80 +- 25 +- 16) x 10^-5 (3.4sigma) for X=pi^0pi^0, and (87 +- 33 +- 22) x 10^-5 (3.5sigma) for X=eta, where the errors are statistical and systematic, respectively. The radiative return process e^+e^- -->gamma psi(2S) populates the same event sample and is used to measure Gamma_{ee}[psi(2S)]=(2.54 +- 0.03 +- 0.11) keV.Comment: 13 ages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2005/, Submitted to PR

Measurement of \cal{B}(D^+ --> mu^+ nu) and the Pseudoscalar Decay Constant fD+f_{D^+}

In 60 pb-1 of data taken on the psi(3770) resonance with the CLEO-c detector, we find 8 D+ to mu+ nu event candidates that are mostly signal, containing only 1 estimated background. Using this statistically compelling sample, we measure preliminary values of B(D+ to mu+ nu) = (3.5 +- 1.4 +- 0.6)*10^{-4}, and determine f_{D+} =(201+- 41+- 17) MeV.Comment: 17 pages postscript, also available through http://www.lns.cornell.edu/public/CONF/2004/, Presented at ICHEP Aug 16-22,2004, Beijing, Chin