245 research outputs found

    TEST OF T AND CP VIOLATION IN LEPTONIC DECAY OF tau^+-

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    The τ±\tau^\pm, highly polarized in the direction of the incident beam, can be obtained from the e±e^\pm collider with the polarized incident e−e^- (and preferably also the e+e^+) beam. This polarization vector \longvec w_i=(w_1+w_2)/(1+w_1w_2) \widehat e_z can be used to construct the TT odd rotationally invariant product (\longvec w_i\times\longvec p_\mu). \longvec w_\mu, where w1w_1 and w2w_2 are longitudinal polarization vectors of e−e^- and e+e^+ respectively; \longvec p_\mu and \longvec w_\mu are the momentum and polarization of the muon in the decay \tau^-\rarrow \mu^-+ \bar\nu_\mu+\nu_\tau. T is violated by the existence of such a term. CP can be tested by comparing it with a similar term in Ï„+\tau^+ decay. If T violation in such a decay is milliweak or stronger, one can find it using the proposed polarized Ï„\tau-charm factory with luminosity of 1 \sim 3 \times 10^{33}/\cm^2/\sec. One can test whether T (and CP) violation is due to the charged Higgs boson exchange by doing a similar experiment for the μ±\mu^\pm decay.Comment: 8 pages, uuencoded postscript file. To obtain a copy of this paper send e-mail to [email protected]

    Search For New Mechanism of CP Violation through Tau Decay and Semilpetonic Decay of Hadrons

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    If CP is violated in any decay process involving leptons it will signify the existense of a new force (called the X boson) responsible for CP violation that may be the key to understanding matter-antimatter asymmetry in the universe. We discuss the signatures of CP violation in (1) the decay of tau lepton, and (2) the semileptonic decay of π\pi, K, D, B and t particles by measuring the polarization of the charged lepton in the decay. We discuss how the coupling constants and their phases of the coupling of the X boson to 9 quark vertices and 3 lepton vertices can be obtained through 12 decay processes.Comment: Latex, 17 page

    Biomechanical investigation of flexor digitorum tendons in trigger finger patients using sonography

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    Trigger finger (TF) has generally been ascribed to primary changes in the first annular (A1) pulley. Repeated friction between the A1 pulley and flexor digitorum tendons could result in swelling of soft tissues, and thus it has been speculated that TF affects tendons’ biomechanical behaviors. However, the pathology mechanism related to these behaviors remains unclear. The purposes of this study are to understand (1) the variations in the morphologies of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) between normal fingers and TFs, (2) the differences in the biomechanical behaviors of the FDP and FDS between normal fingers and TFs in various finger flexion positions, and (3) the effect of various finger positions on the biomechanical behaviors of the FDP and FDS

    A multi-detector array for high energy nuclear e+e- pair spectrosocopy

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    A multi-detector array has been constructed for the simultaneous measurement of energy- and angular correlation of electron-positron pairs produced in internal pair conversion (IPC) of nuclear transitions up to 18 MeV. The response functions of the individual detectors have been measured with mono-energetic beams of electrons. Experimental results obtained with 1.6 MeV protons on targets containing 11^{11}B and 19^{19}F show clear IPC over a wide angular range. A comparison with GEANT simulations demonstrates that angular correlations of e+e−e^+e^- pairs of transitions in the energy range between 6 and 18 MeV can be determined with sufficient resolution and efficiency to search for deviations from IPC due to the creation and subsequent decay into e+e−e^+e^- of a hypothetical short-lived neutral boson.Comment: 20 pages, 8 figure

    Efficacy of concurrent radiotherapy in patients with locally advanced rectal cancer and synchronous metastasis receiving systemic therapy

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    BackgroundNeoadjuvant chemoradiotherapy followed by total mesorectal excision is the standard treatment for patients with nonmetastatic locally advanced rectal cancer (LARC). However, for patients with LARC and synchronous metastasis, the optimal treatment strategy and sequence remain inconclusive. In the present study, we evaluated the efficacy and safety of concurrent radiotherapy in patients with de novo metastatic rectal cancer who received chemotherapy and targeted therapy.MethodsWe retrospectively reviewed the data of 63 patients with LARC and synchronous metastasis who received intensive therapy at the study hospital between April 2015 and November 2018. The included patients were divided into two groups: RT-CT, those who received systemic chemotherapy with targeted therapy and concurrent radiotherapy (for primary rectal cancer), and CT, those who received only systemic chemotherapy with targeted therapy.ResultsTreatment response was better in the RT-CT group than in the CT group. The rate of primary tumor resection (PTR) was higher in the RT-CT group than in the CT group (71.4% and 42.9%, respectively; P = .0286). The RT-CT group exhibited considerably longer local recurrence-free survival (P = .0453) and progression-free survival (PFS; from 13.3 to 22.5 months) than did the CT group (P = .0091); however, the groups did not differ in terms of overall survival (OS; P = .49). Adverse events were almost similar between the groups, except frequent diarrhea, the prevalence of which was higher in the RT-CT group than in the CT group (59.5% and 23.8%, respectively; P = .0075).ConclusionsIn the era of biologics, radiotherapy may increase the resectability of primary rectal tumors, reducing the risk of locoregional failure and prolonging PFS. Concurrent pelvic radiotherapy may not substantially improve OS, which is indicated by metastasis. Hence, the resection of the distant metastases may be essential for improving long-term OS. To further determine the efficacy of concurrent radiotherapy, additional prospective, randomized studies must combine preoperative pelvic radiotherapy with PTR and metastectomy to treat patients with stage IV LARC
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