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IDS Collaboration(Lica, R. et al), & Morales, A. I. (2016). Fast-timing study of the l-forbidden 1/2(+) -> 3/2(+) M1 transition in Sn-129. Phys. Rev. C, 93(4), 044303–7pp.
Abstract: The levels in Sn-129 populated from the beta(-) decay of In-129 isomers were investigated at the ISOLDE facility of CERN using the newly commissioned ISOLDE Decay Station (IDS). The lowest 1/2(+) state and the 3/2(+) ground state in 129Sn are expected to have configurations dominated by the neutron s(1/2) (l = 0) and d(3/2) (l = 2) single-particle states, respectively. Consequently, these states should be connected by a somewhat slow l-forbidden M1 transition. Using fast-timing spectroscopy we havemeasured the half-life of the 1/2(+) 315.3-keV state, T-1/2 = 19(10) ps, which corresponds to a moderately fast M1 transition. Shell-model calculations using the CD-Bonn effective interaction, with standard effective charges and g factors, predict a 4-ns half-life for this level. We can reconcile the shell-model calculations to the measured T-1/2 value by the renormalization of the M1 effective operator for neutron holes.
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Candela-Juan, C., Niatsetski, Y., van der Laarse, R., Granero, D., Ballester, F., Perez-Calatayud, J., et al. (2016). Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions. Med. Phys., 43(4), 1639–1648.
Abstract: Purpose: The aims of this study were (i) to design a new high-dose-rate (HDR) brachytherapy applicator for treating surface lesions with planning target volumes larger than 3 cm in diameter and up to 5 cm in size, using the microSelectron-HDR or Flexitron afterloader (Elekta Brachytherapy) with a Ir-192 source; (ii) to calculate by means of the Monte Carlo (MC) method the dose distribution for the new applicator when it is placed against a water phantom; and (iii) to validate experimentally the dose distributions in water. Methods: The PENELOPE2008 MC code was used to optimize dwell positions and dwell times. Next, the dose distribution in a water phantom and the leakage dose distribution around the applicator were calculated. Finally, MC data were validated experimentally for a 192Ir mHDR-v2 source by measuring (i) dose distributions with radiochromic EBT3 films (ISP); (ii) percentage depth-dose (PDD) curve with the parallel-plate ionization chamber Advanced Markus (PTW); and (iii) absolute dose rate with EBT3 films and the PinPoint T31016 (PTW) ionization chamber. Results: The new applicator is made of tungsten alloy (Densimet) and consists of a set of interchangeable collimators. Three catheters are used to allocate the source at prefixed dwell positions with preset weights to produce a homogenous dose distribution at the typical prescription depth of 3 mm in water. The same plan is used for all available collimators. PDD, absolute dose rate per unit of air kerma strength, and off-axis profiles in a cylindrical water phantom are reported. These data can be used for treatment planning. Leakage around the applicator was also scored. The dose distributions, PDD, and absolute dose rate calculated agree within experimental uncertainties with the doses measured: differences of MC data with chamber measurements are up to 0.8% and with radiochromic films are up to 3.5%. Conclusions: The new applicator and the dosimetric data provided here will be a valuable tool in clinical practice, making treatment of large skin lesions simpler, faster, and safer. Also the dose to surrounding healthy tissues is minimal.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Model-independent measurement of mixing parameters in D-0 -> K-S(0)pi(+)pi(-) decays. J. High Energy Phys., 04(4), 033–26pp.
Abstract: The first model-independent measurement of the charm mixing parameters in the decay D-0 -> K-S(0)pi(+)pi(-) is reported, using a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fb(-1) at a centre-of-mass energy of 7 TeV. The measured values are x = (0.86 +/- 0.53 +/- 0.17) x 10(-2), y = (+0.03 +/- 0.46 +/- 0.13) x 10(-2), where the first uncertainties are statistical and include small contributions due to the external input for the strong phase measured by the CLEO collaboration, and the second uncertainties are systematic.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., Costa, M. J., et al. (2016). Search for anomalous couplings in the Wtb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector. J. High Energy Phys., 04(4), 023–46pp.
Abstract: The electroweak production and subsequent decay of single top quarks is determined by the properties of the Wtb vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular distributions of the decay products of single top quarks produced in the t-channel constrains these parameters simultaneously. The analysis described in this paper uses 4.6 fb(-1) of proton-proton collision data at root s = 7 TeV collected with the ATLAS detector at the LHC. Two parameters are measured simultaneously in this analysis. The fraction f(1) of decays containing transversely polarised W bosons is measured to be 0.37 +/- 0.07 (stat. circle plus syst.). The phase delta_ between amplitudes for transversely and longitudinally polarised W bosons recoiling against lefthanded b-quarks is measured to be -0.014 pi +/- 0.036 pi (stat. circle plus syst.). The correlation in the measurement of these parameters is 0.15. These values result in two-dimensional limits at the 95% confidence level on the ratio of the complex coupling parameters g(R) and V-L, yielding R-e[g(R)/V-L] is an element of [-0.36; 0.10] and Im[g(R)/V-L] is an element of [-0.17; 0.23] with a correlation of 0.11. The results are in good agreement with the predictions of the Standard Model.
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Orrigo, S. E. A. et al, Rubio, B., Gelletly, W., Agramunt, J., Algora, A., & Molina, F. (2016). beta decay of the exotic T-z =-2 nuclei Fe-48, Ni-52, and Zn-56. Phys. Rev. C, 93(4), 044336–18pp.
Abstract: The results of a study of the beta decays of three proton-rich nuclei with T-z = -2, namely Fe-48, Ni-52, and Zn-56, produced in an experiment carried out at GANIL, are reported. In all three cases we have extracted the half-lives and the total beta-delayed proton emission branching ratios. We have measured the individual beta-delayed protons and beta-delayed. rays and the branching ratios of the corresponding levels. Decay schemes have been determined for the three nuclei, and new energy levels are identified in the daughter nuclei. Competition between beta-delayed protons and. rays is observed in the de-excitation of the T = 2 isobaric analog states in all three cases. Absolute Fermi and Gamow-Teller transition strengths have been determined. The mass excesses of the nuclei under study have been deduced. In addition, we discuss in detail the data analysis taking as a test case Zn-56, where the exotic beta-delayed gamma-proton decay has been observed.
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