118016959
Search for Supersymmetry at the Tevatron
This paper reviews some of the most recent results from CDF and D0 experiments on searches for supersymmetry (SUSY) at the Tevatron. We focus on searches for chargino/neutralino, stop, sbottom, and long lived massive SUSY particles, on data samples up to ~1 fb-1. No signal was observed, and constraints are set on the SUSY parameter space.
123114924
ATLAS measurements of the properties of jets for boosted particle searches
Measurements are presented of the properties of high transverse momentum jets, produced in proton-proton collisions at a center-of-mass energy of root s = 7 TeV. The data correspond to an integrated luminosity of 35 pb(-1) and were collected with the ATLAS detector in 2010. Jet mass, width, eccentricity, planar flow and angularity are measured for jets reconstructed using the anti-k(t) algorithm with distance parameters R 0: 6 and 1.0, with transverse momentum p(T) > 300 GeV and pseudorapidity vertical bar eta vertical bar < 2. The measurements are compared to the expectations of Monte Carlo generators that match leading-logarithmic parton showers to leading-order, or next-to-leading-order, matrix elements. The generators describe the general features of the jets, although discrepancies are observed in some distributions.
10189692
Combination of the top-quark mass measurements from the Tevatron collider
We thank the Fermilab staff and technical staffs of the 
participating institutions for their vital contributions and 
acknowledge support from the DOE and NSF (USA), ARC 
(Australia), CNPq, FAPERJ, FAPESP, and FUNDUNESP 
(Brazil), NSERC (Canada), NSC, CAS, and CNSF 
(China), Colciencias (Colombia), MSMT and GACR 
(Czech Republic), the Academy of Finland, CEA, and 
CNRS/IN2P3 (France), BMBF and DFG (Germany), 
DAE and DST (India), SFI (Ireland), INFN (Italy), 
MEXT (Japan), the Korean World Class University 
Program and NRF (Korea), CONACyT (Mexico), FOM 
(Netherlands), MON, NRC KI, and RFBR (Russia), the 
Slovak R&D Agency, the Ministerio de Ciencia e 
Innovacio´n, and Programa Consolider-Ingenio 2010 
(Spain), The Swedish Research Council (Sweden), SNSF 
(Switzerland), STFC and the Royal Society (United 
Kingdom), and the A. P. Sloan Foundation (USA).
118414507
Measurement of branching ratio and $B_s^0$ lifetime in the decay $B_s^0 \rightarrow J/\psi f_0(980)$ at CDF
We present a study of Bs0 decays to the CP-odd final state J/ψ f0(980) with J/ψ → µ+µ- and f0(980) → π+π-. Using pp collision data with an integrated luminosity of 3.8 fb-1 collected by the CDF II detector at the Tevatron we measure a Bs0 lifetime of τ(B0s → J/ψ f0(980)) = 1.70-0.11+0.12(stat) ± 0.03(syst) ps. This is the first measurement of the Bs0} lifetime in a decay to a CP eigenstate and corresponds in the standard model to the lifetime of the heavy Bs0 eigenstate. We also measure the product of branching fractions of B0s → J/ψ f0(980) and f0(980) → π+π- relative to the product of branching fractions of B0s → J/ψφ and φ→K+K- to be Rf0/ψ = 0.257 ± 0.020(stat) ± 0.014(syst), which is the most precise determination of this quantity to date.
12148304
Updated search for the standard model Higgs boson in events with jets and missing transverse energy using the full CDF data set
We present an updated search for the Higgs boson produced in association with a vector boson in the final state with missing transverse energy and two jets. We use the full CDF data set corresponding to an integrated luminosity of 9.45 fb−1 at a proton-antiproton center-of-mass energy of s√=1.96 TeV. New to this analysis is the inclusion of a b-jet identification algorithm specifically optimized for H→bb¯ searches. Across the Higgs boson mass range 90≤mH≤150 GeV/c2, the expected 95% credibility level upper limits on the VH production cross section times the H→bb¯ branching fraction are improved by an average of 14% relative to the previous analysis. At a Higgs boson mass of 125 GeV/c2, the observed (expected) limit is 3.06 (3.33) times the standard model prediction, corresponding to one of the most sensitive searches to date in this final state.
122950163
The performance of the CDF luminosity monitor
Abstract We describe the initial performance of the detector used for the luminosity measurement in the CDF experiment in Run II at the Tevatron. The detector consists of low-mass gaseous Cherenkov counters with high light yield (∼100 photoelectrons) and monitors the process of inelastic p p scattering. It allows for several methods of precise luminosity measurements at peak instantaneous luminosities of 2×10 32 cm −2 s −1 , corresponding to an average of six p p interactions per bunch crossing.
118734333
Revisit of cosmic age problem
We investigate the cosmic age problem associated with 9 extremely old globular clusters in M31 galaxy and 1 very old high-z quasar automatic plate-measuring machine 08279 + 5255 at z = 3.91. These 9 globular clusters have not been used to study the cosmic age problem in the previous literature. By evaluating the age of the Universe in the Lambda cold dark matter model with the observational constraints from the Type Ia supernovae, the baryon acoustic oscillations, the cosmic microwave background, and the independent H(0) measurements, we find that the existence of 5 globular clusters and 1 high-z quasar are in tension (over 2 sigma confidence level) with the current cosmological observations. So if the age estimates of these objects are correct, the cosmic age puzzle still remains in the standard cosmology. Moreover, we extend our investigations to the cases of the interacting dark energy models. It is found that although the introduction of the interaction between dark sectors can give a larger cosmic age, the interacting dark energy models still have difficulty to pass the cosmic age test.
16640761
Recent studies on beam-photoelectron instability in BEPC
An experiment investigating the photoelectron instability has been performed in BEPC at IHEP, China. The betatron oscillation of each bunch was observed and recorded by a single pass beam position monitor system which has a capability to measure the transverse position of every bunch over 16000 turns. The effect of an octupole magnet on the instability was also studied. This paper describes results of those observations and analyses.
109931583
The experimental study on beam-photoelectron instability in BEPC
A vertical coupled bunch instability explained as the photoelectron instability (PEI) was observed in the photon factory at KEK. To further investigate the instability, the experiments on the PEI have been carried out in Beijing Electron Positron Collider (BEPC) with the collaboration between MEP, China and KEK, Japan. Many interesting phenomena have been observed for different sets of parameters.
118392710
Study of $\psi(3686)\to\pi^0 h_c, h_c\to\gamma\eta_c$ via $\eta_c$ exclusive decays
The process $\psi(3686) \to \pi^0 h_c, h_c \to \gamma \eta_c$ has been studied with a data sample of $106 \pm 4$ million $\psi(3686)$ events collected with the BESIII detector at the BEPCII storage ring. The mass and width of the $P$-wave charmonium spin-singlet state $h_c(^1P_1)$ are determined by simultaneously fitting distributions of the $\pi^0$ recoil mass for 16 exclusive $\eta_c$ decay modes. The results, $M(\hc) = 3525.31 \pm 0.11 {\rm (stat.)} \pm 0.14 {\rm (syst.)}$\,MeV/$c^2$ and $\Gamma(\hc) = 0.70 \pm 0.28 \pm 0.22$\,MeV, are consistent with and more precise than previous measurements. We also determine the branching ratios for the 16 exclusive $\eta_c$ decay modes, five of which have not been measured previously. New measurements of the $\eta_c$ line-shape parameters in the $E1$ transition $h_c\to\gamma\eta_c$ are made by selecting candidates in the $h_c$ signal sample and simultaneously fitting the hadronic mass spectra for the 16 $\eta_c$ decay channels. The resulting $\eta_c$ mass and width values are $M(\eta_c) = 2984.49 \pm 1.16 \pm 0.52$\,MeV/$c^2$ and $\Gamma(\eta_c) = 36.4 \pm 3.2 \pm 1.7$\,MeV.
119247229
Reheating phase diagram for single-field slow-roll inflationary models
We investigate the influence on the inflationary predictions from the reheating processes characterized by the $e$-folding number $N_{\mathrm{reh}}$ and the effective equation-of-state parameter $w_{\mathrm{reh}}$ during the reheating phase. For the first time, reheating processes can be constrained in the $N_{\mathrm{reh}}\!-\!w_{\mathrm{reh}}$ plane from Planck 2015. We find that for Higgs inflation with a nonminimal coupling to gravity, the predictions are insensitive to the reheating phase for current CMB measurements. We also find that the spontaneously broken SUSY inflation and axion monodromy inflation with $\phi^{2/3}$ potential, which with instantaneous reheating lie outside or at the edge of the $95\%$ confidence region in the $n_s\!-\!r$ plane from Planck 2015 TT,TE,EE$+$lowP, can well fit the data with the help of reheating processes. Future CMB experiments would put strong constraints on reheating processes.