Near infrared broadband emission characteristics of bismuth-doped aluminophosphate glass have been investigated. Broad infrared emissions peaking at 1210nm, 1173nm and 1300nm were observed when the glass was pumped by 405nm laser diode (LD), 514nm Ar+ laser and 808nm LD, respectively. The full widths at half maximum (FWHMs) are 235nm, 207nm and 300nm for the emissions at 1210nm, 1173nm and 1300nm, respectively. Based on the energy matching conditions, it is suggested that the infrared emission may be ascribed to 3P1? 3P0 transition of Bi+. The broadband infrared luminescent characteristics of the glasses indicate that they are promising for broadband optical fiber amplifiers and tunable lasers.

Broadband infrared luminescence from bismuth-doped germanium oxide glasses prepared by a conventional melting-quenching technique was discovered. The absorption spectrum of the glasses covered a wide range from the visible to the near-infrared wavelength regions and consisted of five broad peaks below 370, 500, 700, 800, and 1000 nm. The fluorescence spectrum exhibited broadband characteristics (FWHM) greater than 300 nm with a maximum at 1300 nm pumped by an 808-nm laser. The fluorescence lifetime at room temperature decreased with increasing Bi2O3 concentration in the glass. Codoping of aluminum and bismuth was indispensable for the broadband infrared luminescence in GeO2:Bi, Al glass.

We report near infrared broadband emission of bismuth-doped barium-aluminum-borate glasses. The broadband emission covers 1.3microm window in optical telecommunication systems. And it possesses wide full width at half maximum (FWHM) of ~200nm and long lifetime as long as 350micros. The luminescent properties are quite sensitive to glass compositions and excitation wavelengths. Based on energy matching conditions, we suggest that the infrared emission may be ascribed to 3P1? 3P0 transition of Bi+. The broad infrared emission characteristics of this material indicate that it might be a promising candidate for broadband optical fiber amplifiers and tunable lasers.

Near-infrared broadband emission from bismuth-tantalum-codoped germanium oxide glasses was observed at room temperature when the glasses were pumped by an 808 nm laser diode. The emission band covered the O, E, S, C, and L bands (1260-1625 nm), with a maximum peak at approximately 1310 nm, a FWHM broader than 400 nm, and a lifetime longer than 200 micros. The observed broadband luminescence was attributed to bismuth clusters in the glasses. Bismuth-tantalum-codoped germanium oxide glass might be promising as amplification media for broadly tunable lasers and wideband amplifiers in optical communications.

The broadband emission in the 1.2~1.6mum region from Li2O-Al2O3-ZnO-SiO2 ( LAZS ) glass codoped with 0.01mol.%Cr2O3 and 1.0mol.%Bi2O3 when pumped by the 808nm laser at room temperature is not initiated from Cr4+ ions, but from bismuth, which is remarkably different from the results reported by Batchelor et al. The broad ~1300nm emission from Bi2O3-containing LAZS glasses possesses a FWHM ( Full Width at Half Maximum ) more than 250nm and a fluorescent lifetime longer than 500mus when excited by the 808nm laser. These glasses might have the potential applications in the broadly tunable lasers and the broadband fiber amplifiers.

Invariant mass spectra for jets reconstructed using the anti-k T and CambridgeAachen algorithms are studied for different jet "grooming" techniques in data corresponding to an integrated luminosity of 5 fb −1 , recorded with the CMS detector in proton-proton collisions at the LHC at a center-of-mass energy of 7 TeV. Leading-order QCD predictions for inclusive dijet and W/Z+jet production combined with parton-shower Monte Carlo models are found to agree overall with the data, and the agreement improves with the implementation of jet grooming methods used to distinguish merged jets of large transverse momentum from softer QCD gluon radiation. The CMS collaboration 33 IntroductionThe variables most often used in analyses of jet production are jet directions and transverse momenta (p T ). However, as jets are composite objects, their invariant masses (m J ) provide additional information that can be used to characterize their properties. One motivation for investigating jet mass is that, at the Large Hadron Collider (LHC), massive standard model (SM) particles such as W and Z bosons and top quarks are often produced with large Lorentz boosts, and, when such particles decay into quarks, the masses of the -1 - JHEP05(2013)090evolved jets can be used to discriminate them from lighter objects generated in quantumchromodynamic (QCD) radiative processes. The same argument also holds for any new massive particles produced at the LHC. For sufficiently large boosts, all the decay products tend to be emitted as collimated groupings into small sections of the detector, and the resulting particles can be clustered into a single jet. Jet "grooming" techniques are designed to separate such merged jets from background. These new techniques have been found to be very promising for identifying decays of highly-boosted W bosons and top quarks, and in searches for Higgs bosons and other massive particles [1]. The main advantage of these grooming techniques is their ability to distinguish high p T jets that arise from decays of massive, possibly new, particles. In addition, their robust performance is valuable in the presence of additional interactions in an event (pileup), which is likely to provide an even greater challenge to such analyses in future higher-luminosity runs at the LHC. Only a few of these promising approaches have been studied in data at the Tevatron [2] or at the LHC [3]. To understand these techniques in the context of searches for new phenomena, the jet mass must be well-modeled through leading-order (LO) or next-toleading-order (NLO) Monte Carlo (MC) simulations. Much recent theoretical work in QCD has focused on the computation of jet mass, including predictions using advances in an effective field theory of jets (soft collinear effective theory, SCET) [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Studies of the kind reported in the present analysis can provide an understanding of the extent to which MC simulations that match matrix-element partons with parton showers can m...

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