Charmonium Spectroscopy Below Open Flavor Threshold
Latest experimental results in the charmonium spectroscopy below D-barD breakup threshold are reviewed.
hep-ex↗
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Impact of slepton generation mixing on the search for sneutrinos - Lepton flavour violation in sneutrino production and decays in the general MSSM
We perform a systematic study of sneutrino production and decays in the Minimal Supersymmetric Standard Model (MSSM) with slepton generation mixing. We study bosonic decays like sneutrino \to slepton^- + W^+/H^+ as well as fermionic ones. We show that the effect of slepton generation mixing on the sneutrino production and decays can be quite large in a significant part of the MSSM parameter space despite the very strong experimental limits on lepton flavour violating processes. This could have an important impact on the search for sneutrinos and the determination of the MSSM parameters at future colliders, such as LHC, ILC, CLIC and muon collider.
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R-Hadron and long lived particle searches at the LHC
If long lived charged particles exist, and produced at the LHC, they may travel with velocity significantly slower than the speed of light. This unique signature was not considered during the design of the LHC experiments, ATLAS and CMS. As a result, hardware and trigger capabilities need to be evaluated. Model independent approaches for finding long lived particles with the LHC experiments are introduced. They are tested using two bench marks, one in GMSB and one in Split SUSY. The focus is on hardware and trigger issues, as well as reconstruction methods developed by ATLAS and CMS. Both experiments suggest time of flight (TOF) based methods. However, the implementation is different. In ATLAS a first beta estimation is done already at the trigger level. CMS also uses dE/dx to estimate beta.
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Searches for Extra Dimensions and for Heavy Resonances in Dilepton, Diphoton, Electron + Photon and Electron + Missing ET Final States with the D0 Detector
The high mass spectrum of lepton and photon pairs is sensitive to a broad array of new physics. Examples include searches for extra dimensions in the dielectron and diphoton channels. A direct search for electron compositeness is possible in the production of excited electrons decaying into an electron and a photon. In addition, the electron plus missing transverse energy data sample can be searched for a W' boson. Latest results in searches in the high mass dielectron, diphoton, electron plus photon, and electron plus missing transverse energy channels obtained by the D0 experiment at the Tevatron are reported, using a data set corresponding to an integrated luminosity of about 1 inverse femtobarn. Since no significant excess is observed in the data in all cases, limits are set which improve on previous searches.
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Study of $ψ(2S)$ decays into $γK^+K^-$ and $γπ^+π^-$
Radiative charmonium decays from the BESII sample of 14$\times10^{6}$ $ψ(2S)$-events into two different final states, $γK^+K^-$ and $γπ^+π^-$, are analyzed. Product branching fractions for $ψ(2S)\toγX\to γπ^+π^-$, $γK^+K^-$ are given, where $X=f_2(1270)$, $f_0(1500)$, and $f_0(1710)$ in $π^+π^-$ and $f_2(1270)$, $f_2'(1525)$, and $f_0(1700)$ in $K^+K^-$. An angular analysis gives the ratios of the helicity projections for the $f_2(1270)$ in $ψ(2S)\toγf_2(1270)\toγπ^+π^-$.
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Prospects to Measure the Higgs Boson Mass and Cross Section in ee-->ZH Using the Recoil Mass Spectrum
The process ee-->ZH allows to measure the Higgs boson in the recoil mass spectrum against the Z boson without any assumptions on the Higgs boson decay. We performed a full simulation and reconstruction of ee-->ZH using the MOKKA and MARLIN packages describing the LDC detector. The Z is reconstructed from its decays into electrons and muons. The mass of the Higgs boson is set to 120 GeV. Assuming a centre-of-mass energy of 250 GeV and an integrated luminosity of 50/fb the Higgs boson mass and the Higgs-strahlung cross section can be measured with a precision of 120 MeV and 9%, respectively.
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Extracting the Gluon Piece of the Spin Puzzle: New Inclusive Jet Results from STAR
This contribution presents the most recent mid-rapidity inclusive jet results from 3 pb^-1 of data collected from longitudinally polarized proton collisions at sqrt(s)=200 GeV during the 2005 RHIC run. The inclusive jet asymmetry, a_LL, with it's increased transverse momentum range and precision, provides strong constraints on the gluon helicity distribution when compared with existing next-to-leading order perturbative QCD evaluations.
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On a possible origin of a resonance-like structure in the two-photon invariant mass spectrum of the reaction pp->ppgg
We show that the resonance-like structure found by the \emph{CELSIUS-WASA Collaboration} in the two-photon invariant mass spectrum of the reaction $pp \to pp γγ$ is rather a signature of the $NN$-decoupled dibaryon resonance $d^\star_1$(1956) that is produced in the radiative process $pp \to γd^\star_1$ and then undergoes radiative decay into two protons $d^\star_1 \to pp γ$. It is found that a contribution of the dibaryon mechanism $pp \to γd^\star_1 \to pp γγ$ of the reaction $pp \to pp γγ$ to the invariant mass spectrum of its photon pairs can reasonably well reproduce the experimentally observed spectrum in the vicinity of the resonance-like structure.
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The physics case of DAFNE-2
We present the physics case of DAFNE-2, an $e^+e^-$ collider expected to deliver 20-50 fb$^{-1}$ at the $ϕ(1020)$ peak, and $\sim$ 5 fb$^{-1}$ in the energy region between 1 and 2.5 GeV.
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Strategy for early SUSY searches at ATLAS
The CERN Large Hadron Collider (LHC) is scheduled to commence operation in 2008 and inclusive searches for supersymmetry (SUSY) will be one of our primary tasks in the first days of LHC operation. It is certain that the final state of multijets + missing transverse energy will provide a superior performance in SUSY searches. Strategies to understand the instrumental background and to understand the Standard Model (SM) background are still under development and are urgent issues for the coming data. We describe the strategy for early SUSY searches at the ATLAS experiment using the fist data corresponding to an integrated luminosity up to 1fb^-1, which comprises much progress in the data-driven technique for the SM background estimations.
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Search for Supersymmetry in Trilepton Final States with the DO Detector
Data taken by the DO experiment at the proton-antiproton collider at Tevatron has been analyzed to search for signatures consistent with decay of charginos and neutralinos. The search is performed in final states with three leptons and missing transverse energy. No excess above the standard model expectation is observed and limits on the production cross section times branching fraction are set.
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New developments in PHOKHARA Monte Carlo generator
The present status of the physics program, which led to the development of the Monte Carlo event generator PHOKHARA is described. The possibility of using the radiative return method in various aspects of hadronic physics, from the measurement of the hadronic cross section, to detailed investigations of the hadronic dynamics is emphasized. New results are presented showing how to measure baryon form factors using the knowledge of their spin in baryon-antibaryon production with subsequent decay.
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Searches for Higgs and BSM at the Tevatron
This paper presents an overview of recent experimental direct searches for Higgs-boson and beyond-the-standard-model (BSM) physics shown in the plenary session at the SUSY07 conference. The results reported correspond to an integrated luminosity of up to 2 fb-1 of Run II data from $p\bar{p}$ collisions collected by the CDF and D0 experiments at the Fermilab Tevatron Collider. Searches covered include: the standard model (SM) Higgs boson (including sensitivity projections), the minimal supersymmetric extension of the standard model (MSSM), charged Higgs bosons and extended Higgs models, supersymmetric decays that conserve R-parity, gauge-mediated supersymmetric breaking models, long-lived particles, leptoquarks, extra gauge bosons, extra dimensions, and finally signature-based searches. Given the excellent performance of the collider and the continued productivity of the experiments, the Tevatron physics potential looks very promising for discovery in the coming larger data sets. In particular, the Higgs boson could be observed if its mass is light or near 160 GeV.
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The SuperNEMO double beta decay experiment
The SuperNEMO project studies the feasibility of employing a technique of tracking plus calorimetry to search for neutrinoless double beta decay in 100 kg of enriched isotopes. It aims to reach an effective neutrino mass sensitivity of 50 meV. The current status of the SuperNEMO R&D programme is described, focusing on the main areas of improvement.
physics.ins-det↗
Distributions for Higgs + jet at hadron colliders: MSSM vs SM
We present pseudorapidity and transverse momentum distributions for the cross section for the production of the lightest neutral Higgs boson in association with a high-p_T hadronic jet, calculated in the framework of the minimal supersymmetric standard model. We discuss the theoretical predictions for the differential cross sections at the Large Hadron Collider and the Tevatron. In particular, we present the differences in the distributions compared to the Standard Model.
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Systematics and background suppression in the KATRIN experiment
Recent neutrino mass experiments at Mainz and Troitsk using tritium beta-decay have reached their sensitivity potential, yielding upper limits of about 2 eV/c^2 for the electron antineutrino mass. The KArlsruhe TRItium Neutrino experiment (KATRIN), designed to reach a sensitivity of 0.2 eV/c^2 (90% C.L.), will improve the signal rate by a factor of about 100 with respect to previous experiments while maintaining the same low background level at an enhanced energy resolution of 0.93 eV of the spectrometer which is scaled up by a factor of 10 in linear dimensions. This low background rate can only be achieved by active and passive reduction of the background components induced by the spectrometer itself and in the detector region. Furthermore, sources of systematic errors such as energy losses inside the tritium source or fluctuations of the energy scale of the spectrometer need to be carefully controlled and analysed. An overview of KATRIN's method to reduce the background rate and to determine the systematics as well as the sensitivity on the neutrino mass will be presented.
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Inclusive Search for Squarks and Gluinos Production at CDF
We present preliminary results on a search for squarks and gluinos in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV and based on 1.1 fb-1 of data collected by the CDF detector in the Tevatron Run II. Events with multiple jets of hadrons and large missing transverse energy in the final state are studied within the framework of minimal supergravity and assuming R-parity conservation. No excess with respect to Standard Model predictions is observed and new limits on the gluino and squark masses are extracted.
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Search for Higgs decays to tau lepton pairs at the Tevatron
We present a search for neutral supersymmetric Higgs bosons decaying to tau+tau- pairs produced in ppbar collisions at sqrt{s}=1.96 TeV. The data have been collected with the CDF II and D0 detectors at the Tevatron collider at Fermilab (1 fb^-1 of integrated luminosity per experiment). No significant excess above the standard model backgrounds is observed. We set exclusion limits on the Higgs production cross-section times the branching fraction of its decay to tau+tau- pairs for Higgs masses in the range from 90 to 250 GeV/c^2. We also set exclusion limits on MSSM parameters m_A and tan_beta in several benchmark scenarios.
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