120266426
Inclusive charged hadron production in two photon collisions at LEP
Inclusive charged hadron production, $ m{e}^{+} m{e}^{-} ightarrow m{e}^{+} m{e}^{-}$ h$^{pm}$ X, is studied using 414 pb$^{-1}$ of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 202 GeV. Single particle inclusive differential cross sections are measured as a function of the particle transverse momentum, $p_t$, and pseudo-rapidity, $eta$. For $ p_t le 1.5$ GeV, the data are well described by an exponential, typical of soft hadronic processes. For higher $p_t$, the onset of perturbative QCD processes is observed. The $pi^{pm}$ production cross section for $p_t 5$ GeV is much higher than the NLO QCD predictions.
19719907
Trigger System of BESIII
The trigger system of Beijing Spectrometer III, part of the upgrade of Beijing Electron Positron Collider, has been designed and implemented, and is ready for installation. This paper describes briefly the system components, its characteristics, and some technical issues. The system consists mainly of four parts: MDC (drift chamber) tracking subsystem, EMC (electromagnetic calorimeter) subsystem, TOF (time of flight) subsystem and global trigger. Some highlights in designing of this system includes: trigger scheme optimization with software simulation; optical transmission between trigger and FEEs to realize isolation with FEEs to avoid ground loop current interference; designed with most latest FPGA (Xilinx Spartan 3, VirtexII Pro...) for simplicity, high reliability and easy maintenance and hence smaller system; FPGA in-system programming or firmware online downloadable via onboard, panel connector and/or VME bus for modification flexibility during commissioning. Different from the usual fix delay data transmission from FEE to trigger, the RocketIO has been used as SEDES.
203030065
Search for anomalous couplings in the Higgs sector at LEP
Anomalous couplings of the Higgs boson are searched for through the processes e+e-→Hγ, e+e -→e+e-H and e+e -→HZ. The mass range 70 GeV<mH<190 GeV is explored using 602 pb-1 of integrated luminosity collected with the L3 detector at LEP at centre-of-mass energies s=189-209 GeV. The Higgs decay channels H→ff, H→γγ, H→Zγ and H→WW(*) are considered and no evidence is found for anomalous Higgs production or decay. Limits on the anomalous couplings d, d B, Δg1 Z, Δκγ and ξ2 are derived as well as limits on the H→γγ and H→Zγ decay rates. © 2004 Published by Elsevier B.V.
208868428
f1(1285) formation in two-photon collisions at LEP
Abstract The ηπ + π − final state in two-photon collisions is studied with the L3 detector at LEP, at centre-of-mass energies from 183 to 209 GeV with an integrated luminosity of 664.6 pb −1 . The f 1 (1285) meson is observed and the Q 2 dependence of its production is compared to different form factor models. The γγ -coupling parameter Γ γγ is found to be 3.5±0.6(stat.)±0.5(sys.) keV. The branching fraction Γ (f 1 (1285)→a 0 π )/ Γ (f 1 (1285)→ ηππ ) is also measured.
188198310
Preliminary design of BES-III trigger system
126182293
Evidence of psi(3770) nonD anti-D decay to J / psi pi+ pi-
55815228
Muon Collider Higgs Factory for Snowmass 2013
Author(s): Alexahin, Y; Ankenbrandt, CM; Cline, DB; Conway, A; Cummings, MA; Benedetto, VD; Eichten, E; Gatto, C; Grinstein, B; Gunion, J; Han, T; Hanson, G; Hill, CT; Ignatov, F; Johnson, RP; Lebedev, V; Lipton, R; Liu, Z; Markiewicz, T; Mazzacane, A; Mokhov, N; Nagaitsev, S; Neuffer, D; Palmer, M; Purohit, MV; Raja, R; Striganov, S; Summers, D; Terentiev, N; Wenzel, H | Abstract: We propose the construction of, and describe in detail, a compact Muon Collider s-channel Higgs Factory.
118168794
Observation of $Z_c(3900)$ both by BESIII and Belle
Using $525$ pb$^{-1}$ data collected with the BESIII detector at $e^+e^-$ central-of-mass energy 4.26 GeV, the BESIII Collaboration observed a charged charmoniumlike state $Z_c(3900)\to\pi^{\pm}J/\psi$ with mass $M[Z_c(3900)]=3899.0\pm 3.6 \pm 4.9$ MeV/c$^2$, and width $\Gamma[Z_c(3900)]=46\pm 10 \pm 20$ MeV. The significance of this state was estimated to be $>8\sigma$ in all kinds of systematic tests. Using $967$ fb$^{-1}$ data recorded by the Belle detector on or near $\Upsilon(nS)$, n=1, 2, $\cdots$, 5 resonances, the $e^+e^- \to \pi^+\pi^-J/\psi$ process has been studied through initial-state-radiation (ISR) method. Except for the $Y(4260)$ resonance, an intermediate state $Z(3900)^{\pm}$ has been observed in the $\pi^{\pm}J/\psi$ mass spectrum, with significance $>5.2\sigma$. The measured mass $M[Z(3900)^{\pm}]=3894.5\pm6.6\pm4.5$ MeV/c$^2$ and width $\Gamma[Z(3900)^{\pm}]=63\pm24\pm26$ MeV, shows good agreement with the BESIII measurement within errors, which means $Z_c(3900)$ and $Z(3900)^{\pm}$ is the same state.
121627789
Pseudoscalar Meson and Charmed Baryon Scattering Lengths
We have calculated the scattering lengths between the pseudoscalar meson and charmed triplet, sextet, and excited sextet baryon to the third order with the heavy baryon chiral perturbation theory. The chiral expansion of the pion channels converges well.
117349439
Probing supergravity unified theories at the Large Hadron Collider
The discovery of supersymmetry is one of the major goals of the current experiments at the Tevatron and in proposed experiments at the Large Hadron Collider (LHC). However when sparticles are produced the signatures of their production will to a significant degree depend on their hierarchical mass patterns. Here we investigate hierarchical mass patterns for the four lightest sparticles within one of the leading candidate theories - the SUGRA model. Specifically we analyze the hierarchies for the four lightest sparticles for the mSUGRA as well as for a general class of supergravity unified models including nonuniversalities in the soft breaking sector. It is shown that out of nearly $10^4$ possibilities of sparticle mass hierarchies, only a small number survives the rigorous constraints of radiative electroweak symmetry breaking, relic density and other experimental constraints. The signature space of these mass patterns at the LHC is investigated using a large set of final states including multi-leptonic states, hadronically decaying $\tau$s, tagged $b$ jets and other hadronic jets. In all, we analyze more than 40 such lepton plus jet and missing energy signatures along with several kinematical signatures such as missing transverse momentum, effective mass, and invariant mass distributions of final state observables. It is shown that a composite analysis can produce significant discrimination among sparticle mass patterns allowing for a possible identification of the source of soft breaking. While the analysis given is for supergravity models, the techniques used in the analysis are applicable to wide class of models including string and brane models.
118669821
LHC constraints on dark matter with (130 GeV) gamma ray lines
Dark matter annihilation into photons in our galaxy would constitute an exciting indirect signal of its existence, as underscored by tentative evidence for 130 GeV dark matter in Fermi/LAT data. Models that give a large annihilation cross section into photons typically require the dark matter to couple to, or be composed of, new charged particles, that can be produced in colliders. We consider the LHC constraints on some representative models of these types, including the signals of same-sign dileptons, opposite-sign dileptons, events mimicking the production and decay of excited leptons, four-photon events, resonant production of composite vectors decaying into two photons, and monophoton events.