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Perez-Ramos, R. (2011). The Internal Structure Of Jets At Colliders: Light And Heavy Quark Inclusive Hadronic Distributions. Int. J. Mod. Phys. E, 20(7), 1616–1622.
Abstract: In this paper, we report our results on charged hadron multiplicities of heavy quark initiated jets produced in high energy collisions. After implementing the so-called dead cone effect in QCD evolution equations, we find that the average multiplicity decreases significantly as compared to the massless case. Finally, we discuss the transverse momentum distribution of light quark initiated jets and emphasize the comparison between our predictions and CDF data.
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Pich, A., Rosell, I., & Sanz-Cillero, J. J. (2011). The vector form factor at the next-to-leading order in 1/N-C: chiral couplings L-9(mu) and C-88(mu)-C-90(mu). J. High Energy Phys., 02(2), 109–23pp.
Abstract: Using the Resonance Chiral Theory Lagrangian, we perform a calculation of the vector form factor of the pion at the next-to-leading order (NLO) in the 1/N-C expansion. Imposing the correct QCD short-distance constraints, one fixes the amplitude in terms of the pion decay constant F and resonance masses. Its low momentum expansion determines then the corresponding O(p(4)) and O(p(6)) low-energy chiral couplings at NLO, keeping control of their renormalization scale dependence. At mu(0) = 0.77 GeV, we obtain L-9(mu(0)) = (7.9 +/- 0.4).10(-3) and C-88(mu(0)) – C-90(mu(0)) = (-4.6 +/- 0.4).10(-5).
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Pino, F., Roe, N., Orero, A., Falcon, C., Rojas, S., Benlloch, J. M., et al. (2011). Development of a variable-radius pinhole SPECT system with a portable gamma camera. Rev. Esp. Med. Nucl., 30(5), 286–291.
Abstract: Objective: To develop a small-animal SPECT system using a low cost commercial portable gamma camera equipped with a pinhole collimator, a continuous scintillation crystal and a position-sensitive photomultiplier tube. Material and methods: The gamma camera was attached to a variable radius system, which enabled us to optimize sensitivity and resolution by adjusting the radius of rotation to the size of the object. To investigate the capability of the SPECT system for small animal imaging, the dependence of resolution and calibration parameters on radius was assessed and acquisitions of small phantoms and mice were carried out. Results: Resolution values, ranging from 1.0 mm for a radius of 21.4 mm and 1.4 mm for a radius of 37.2 mm were obtained, thereby justifying the interest of a variable radius SPECT system. Conclusions: The image quality of phantoms and animals were satisfactory, thus confirming the usefulness of the system for small animal SPECT imaging.
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Das, S. P., & Drees, M. (2011). CP-violating supersymmetric Higgs boson at the Tevatron and LHC. Phys. Rev. D, 83(3), 035003–17pp.
Abstract: We analyze the prospect for observing the intermediate neutral Higgs boson (h(2))in its decay to two lighter Higgs bosons (h(1)) at the presently operating hadron colliders in the framework of the CP-violating minimal supersymmetric standard model using the PYTHIA event generator. We consider the lepton + 4-jets + E-T channel from associate Wh(2) production, with Wh(2) -> Wh(1)h(1) -> l -> l nu lb (b) over barb (b) over bar. We require two, three or four tagged b jets. We explicitly consider all relevant standard model backgrounds, treating c jets separately from light flavor and gluon jets and allowing for mistagging. We find that it is very hard to observe this signature at the Tevatron, even with 20 fb(-1) of data, in the LEP-allowed region of parameter space due to the small signal efficiency, even though the background is manageable. At the LHC, a priori huge standard model backgrounds can be suppressed by applying judiciously chosen kinematical selections. After all cuts, we are left with a signal cross section of around 0.5 fb, and a signal to background ratio between 1.2 and 2.9. According to our analysis this Higgs signal should be viable at the LHC in the vicinity of present LEP exclusion once 20 to 50 fb(-1) of data have been accumulated at root s = 14 TeV.
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Puppe, P., Frekers, D., Adachi, T., Akimune, H., Aoi, N., Bilgier, B., et al. (2011). High-resolution ((3)He,t) reaction on the double-beta decaying nucleus (136)Xe. Phys. Rev. C, 84(5), 051305–5pp.
Abstract: A ((3)He, t) charge-exchange reaction experiment on the double-beta decaying nucleus (136)Xe has been performed at an incident energy of 420 MeV with the objective to measure the Gamow-Teller (GT) strength distribution in (136)Cs. The measurements have been carried out at the dispersion-matched WS beam line and the Grand Raiden spectrometer of the Research Center for Nuclear Physics in Osaka, where an energy resolution of 42 keV was achieved. A new gas cell with thin windows made of polyethylene naphthalate has been employed as a target. The extracted GT strength distribution is confronted with the rather long 2 nu beta beta decay half-life of (136)Xe.
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