1,530 research outputs found

    Modeling missing transverse energy in V+jets at CERN LHC

    Full text link
    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

    Full text link
    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

    Механизмы развития лекарственной устойчивости Mycobacterium tuberculosis: есть ли шанс победить?

    Get PDF
    The scientific review provides current information on the current epidemiological status of tuberculosis in our country and the world, genetic adaptability and the evolution of Mycobacterium tuberculosis. The well-known and recently discovered molecular targets of aggression of this microorganism are described, and possible methods of circumventing the resistance of the Office to existing and developed drugs are presented. Objective: to create a scientific analytical review, which allows you to form an idea of the basic principles of development of the mechanisms of drug resistance of M. tuberculosis, as well as ways to overcome them with the possibility of further development of the chosen direction with the involvement of reputable scientific groups and practical implementation. Methods. scientific analysis of international reports, highly indexed scientific articles and clinical protocols. Results. Ihanks to the conducted analytical work, critical biological markers of M. tuberculosis immunity to anti-tuberculosis therapy were identified, which protect it from pharmacological intervention by the person and do not adequately sanitize the centers of inflammation in the patient's body. Methods have been proposed for disintegrating the mechanisms of drug resistance, which will bring the algorithms for treating tuberculosis infection to a new level. Conclusion. The analyzed information will contribute to deepening and expanding the knowledge of specialists involved in the fight against tuberculosis about the importance of implementing a personalized approach in the provision of medical care to TB patients, taking into account the studied molecular indicators of resistance to standardized and developed drugs.В научном аналитическом обзоре представлена актуальная информация о современном эпидемиологическом статусе по туберкулезу в нашей стране и мире, генетической приспосабливаемости и эволюционировании Mycobacterium tuberculosis. Описаны известные и недавно открытые молекулярные мишени агрессии данного микроорганизма, представлены возможные методические приемы обхода невосприимчивости микобактерии туберкулеза (МБТ) к существующим и разрабатываемым препаратам. Целью обзора явилось формирование представления о принципах развития механизмов лекарственной резистентности МБТ, а также способах, позволяющих их преодолеть, с возможностью дальнейшей проработки выбранного направления с привлечением авторитетных научных групп и практической реализацией. Материалы и методы. Научный анализ высокоиндексированных международных докладов, статей и клинических протоколов. Результаты. Выделены критические биологические маркеры невосприимчивости M. tuberculosis к противотуберкулезной терапии, которые защищают от фармакологического вмешательства со стороны человека и не позволяют адекватно санировать очаги воспаления в организме больного. Предложены способы дезинтеграции механизмов лекарственной резистентности, что позволит вывести алгоритмы лечения туберкулезной инфекции на новый уровень. Заключение. С учетом изученных молекулярных индикаторов сопротивляемости к стандартизированным и разрабатываемым лекарственным препаратам полученные результаты анализа информации о важности реализации персонализированного подхода в оказании медицинской помощи фтизиатрическим пациентам позволят углубить и расширить кругозор специалистов, участвующих в борьбе с туберкулезом

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

    Full text link
    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

    Observation of a Narrow Resonance of Mass 2.46 GeV/c^2 Decaying to D_s^*+ pi^0 and Confirmation of the D_sJ^* (2317) State

    Full text link
    Using 13.5 inverse fb of e+e- annihilation data collected with the CLEO II detector we have observed a narrow resonance in the Ds*+pi0 final state, with a mass near 2.46 GeV. The search for such a state was motivated by the recent discovery by the BaBar Collaboration of a narrow state at 2.32 GeV, the DsJ*(2317)+ that decays to Ds+pi0. Reconstructing the Ds+pi0 and Ds*+pi0 final states in CLEO data, we observe peaks in both of the corresponding reconstructed mass difference distributions, dM(Dspi0)=M(Dspi0)-M(Ds) and dM(Ds*pi0)=M(Ds*pi0)-M(Ds*), both of them at values near 350 MeV. We interpret these peaks as signatures of two distinct states, the DsJ*(2317)+ plus a new state, designated as the DsJ(2463)+. Because of the similar dM values, each of these states represents a source of background for the other if photons are lost, ignored or added. A quantitative accounting of these reflections confirms that both states exist. We have measured the mean mass differences = 350.0 +/- 1.2 [stat] +/- 1.0 [syst] MeV for the DsJ*(2317) state, and = 351.2 +/- 1.7 [stat] +/- 1.0 [syst] MeV for the new DsJ(2463)+ state. We have also searched, but find no evidence, for decays of the two states via the channels Ds*+gamma, Ds+gamma, and Ds+pi+pi-. The observations of the two states at 2.32 and 2.46 GeV, in the Ds+pi0 and Ds*+pi0 decay channels respectively, are consistent with their interpretations as (c anti-strange) mesons with orbital angular momentum L=1, and spin-parities of 0+ and 1+.Comment: 16 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, version to be published in Physical Review D; minor modifications and fixes to typographical errors, plus an added section on production properties. The main results are unchanged; they supersede those reported in hep-ex/030501

    Observation of the ^1P_1 State of Charmonium

    Get PDF
    The spin-singlet P-wave state of charmonium, hc(1P1), has been observed in the decay psi(2S) -> pi0 hc followed by hc -> gamma etac. Inclusive and exclusive analyses of the M(hc) spectrum have been performed. Two complementary inclusive analyses select either a range of energies for the photon emitted in hc -> gamma etac or a range of values of M(etac). These analyses, consistent with one another within statistics, yield M(h_c) =[3524.9 +/- 0.7 (stat) +/- 0.4 (sys)]MeV/c^2 and a product of the branching ratios B_psi(psi(2S) -> pi0 hc) x B_h(hc -> gamma etac) = [3.5 +/- 1.0 (stat) +/- 0.7 (sys)] x 10^{-4}. When the etac is reconstructed in seven exclusive decay modes, 17.5 +/- 4.5 hc events are seen with an average mass M(hc) = [3523.6 +/- 0.9 (stat) +/- 0.5 (sys)] MeV/c^2, and B_psi x B_h = [5.3 +/- 1.5 (stat) +/- 1.0 (sys)] x 10^{-4}. Because the inclusive and exclusive data samples are largely independent they are combined to yield an overall mass M(hc) = [3524.4 +/- 0.6 (stat) +/- 0.4 (sys)]MeV/c^2 and product of branching ratios B_psi x B_h = [4.0 +/- 0.8 (stat) +/- 0.7 (sys)] x 10^{-4}. The hc mass implies a P-wave hyperfine splitting Delta M_{HF}(1P) \equiv M(1^3P)-M(1^1P_1) = [1.0 +/- 0.6 (stat) +/- 0.4 (sys)] MeV/c^2.Comment: 38 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2005/, Submitted to PR

    Search for X(3872) in gamma gamma Fusion and ISR at CLEO

    Full text link
    We report on a search for the recently reported X(3872) state using 15.1 fb^{-1} e+ e- data taken in the \sqrt{s} = 9.46-11.30 GeV region. Separate searches for the production of X(3872) in untagged gamma-gamma fusion and e+ e- annihilation following initial state radiation (ISR) are made by taking advantage of the unique correlation of J/psi -> l+ l- in X(3872) decay to pi+ pi- J/psi. No signals are observed in either case, and 90% confidence upper limits are established as (2J+1)\Gamma_{\gamma\gamma}B(X -> pi+ pi- J/psi) < 12.9 eV and \Gamma_{ee}B(X -> pi+ pi- J/psi) < 8.3 eV.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)

    Full text link
    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
    corecore