688 research outputs found

    Collective Modes in a Slab of Interacting Nuclear Matter: The effects of finite range interactions

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    We consider a slab of nuclear matter and investigate the collective excitations, which develop in the response function of the system. We introduce a finite-range realistic interaction among the nucleons, which reproduces the full G-matrix by a linear combination of gaussian potentials in the various spin-isospin channels. We then analyze the collective modes of the slab in the S=T=1 channel: for moderate momenta hard and soft zero-sound modes are found, which exhaust most of the excitation strength. At variance with the results obtained with a zero range force, new "massive" excitations are found for the vector-isovector channel .Comment: 14 pages, TeX, 5 figures (separate uuencoded and tar-compressed postscript files), Torino preprint DFTT 6/9

    Conditions for detecting CP violation via neutrinoless double beta decay

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    Neutrinoless double beta decay data together with information on the absolute neutrino masses obtained from the future KATRIN experiment and/or astrophysical measurements give a chance to find CP violation in the lepton sector with Majorana neutrinos. We derive and discuss necessary conditions which make discovery of such CP violation possible for the future neutrino oscillation and mass measurements data.Comment: 15 pages, 4 figures, RevTe

    Quasielastic Electron Scattering from Nuclei: Random-Phase vs. Ring Approximations

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    We investigate the extent to which the nuclear transverse response to electron scattering in the quasielastic region, evaluated in the random-phase approximation can be described by ring approximation calculations. Different effective interactions based on a standard model of the type g'+V_pi+V_rho are employed. For each momentum transfer, we have obtained the value of g'_0 permitting the ring response to match the position of the peak and/or the non-energy weighted sum rule provided by the random-phase approach has been obtained. It is found that, in general, it is not possible to reproduce both magnitudes simultaneously for a given g'_0 value.Comment: 7 pages, 4 Postscript figures, to appear in Physical Review

    Signals of non-extensive statistical mechanics in high-energy nuclear collisions

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    Starting from the presence of non-ideal plasma effects due to strong coupled plasma in the early stage of relativistic heavy-ion collisions, we investigate, from a phenomenological point of view, the relevance of non-conventional statistical mechanics effects on the rapidity spectra of net proton yield at AGS, SPS and RHIC. We show that the broad rapidity shape measured at RHIC can be very well reproduced in the framework of a non-linear relativistic Fokker-Planck equation which incorporates non-extensive statistics and anomalous diffusion

    The effects of nonextensive statistics on fluctuations investigated in event-by-event analysis of data

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    We investigate the effect of nonextensive statistics as applied to the chemical fluctuations in high-energy nuclear collisions discussed recently using the event-by-event analysis of data. It turns out that very minuite nonextensitivity changes drastically the expected experimental output for the fluctuation measure. This results is in agreement with similar studies of nonextensity performed recently for the transverse momentum fluctuations in the same reactions.Comment: Revised version, to be published in J. Phys. G (2000

    The prevalence and pattern of chemotherapy-induced peripheral neuropathy among women with breast cancer receiving care in a large community oncology practice

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    Purpose To describe the prevalence, severity, and risk factors of chemotherapy-induced peripheral neuropathy (CIPN) and its impact on function and quality of life (QOL) among women treated for breast cancer in a large U.S. Community Oncology practice. Methods Women previously treated with taxane-based chemotherapy for early-stage breast cancer completed the EORTC QLQ–C30, QLQ–BR23, and QLQ–CIPN20. Subscales are scored 0–100; higher scores indicate greater symptom severity. Pre-specified hypotheses were tested. Results 126 women with mean age 56.7 years (SD 11.8) were stage I–II (79.4%) or stage III (20.6%) at the time of the survey; 65.1% were White and 27.8% were Black or African American. The mean time since last taxane chemotherapy cycle was 144.9 weeks (SD 112.9). 73.0% reported having CIPN. QLQ–CIPN20 mean scores for the sensory, motor, and autonomic subscales were 18.9 (SD 23.1), 18.6 (SD 18.7), and 17.1 (SD 21.8), respectively. CIPN symptom severity was negatively correlated with global health status/QOL and physical and role functioning (range of r = -0.46 to -0.72). It was not associated with age, body mass index, diabetes, or cumulative taxane dosage, but was greater for Black or African American women (e.g., sensory, p<0.002). CIPN sensory impairment was marginally greater for patients treated with paclitaxel compared to docetaxel (p<0.064). Conclusions CIPN was prevalent in this community oncology practice and significantly impacts function and QOL. These data highlight the importance of developing methods to mitigate CIPN, and for screening for CIPN particularly among Black or African American women

    On the role of the effective interaction in quasi-elastic electron scattering calculations

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    The role played by the effective residual interaction in the transverse nuclear response for quasi-free electron scattering is discussed. The analysis is done by comparing different calculations performed in the Random--Phase Approximation and Ring Approximation frameworks. The importance of the exchange terms in this energy region is investigated and the changes on the nuclear responses due to the modification of the interaction are evaluated. The calculated quasi-elastic responses show clear indication of their sensibility to the details of the interaction and this imposes the necessity of a more careful study of the role of the different channels of the interaction in this excitation region.Comment: 16 pages, 4 Postscript figure

    Hadron production in heavy relativistic systems

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    We investigate particle production in heavy-ion collisions at RHIC energies as function of incident energy, and centrality in a three-sources Relativistic Diffusion Model. Pseudorapidity distributions of produced charged hadrons in Au + Au and Cu + Cu collisions at sqrt(s_NN) = 19.6 GeV, 62.4 GeV, 130 GeV and 200 GeV show an almost equilibrated midrapidity source that tends to increase in size towards higher incident energy, and more central collisions. It may indicate quark-gluon plasma formation prior to hadronization.Comment: 8 pages, 3 figure

    Limits on \boldmath n {\bar n} oscillations from nuclear stability

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    The relationship between the lower limit on the nuclear stability lifetime as derived from the non disappearance of `stable` nuclei (Td ≳ 5.4 × 1031T_{d}~\gtrsim~5.4~\times~10^{31} yr), and the lower limit thus implied on the oscillation time (τnnˉ)(\tau_{n \bar n}) of a possibly underlying neutron-antineutron oscillation process, is clarified by studying the time evolution of the nuclear decay within a simple model which respects unitarity. The order-of-magnitude result τnnˉ≈2(Td/Γnˉ)1/2>2×108\tau_{n \bar n} \approx 2 (T_{d}/\Gamma_{\bar n})^{1/2} > 2 \times 10^{8} sec, where Γnˉ\Gamma_{\bar n} is a typical nˉ\bar n nuclear annihilation width, agrees as expected with the limit on τnnˉ\tau_{n \bar n} established by several detailed nuclear physics calculations, but sharply disagreeing by 15 orders of magnitude with a claim published recently in Phys. Rev. CRAP.Comment: 8 pages; this PRC version (accepted for publication, November 4 1999) differs from the original version only by a few minor editorial change
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