1,151 research outputs found

    Rare Radiative B -> \tau^+ \tau^- \gamma decay in the two Higgs doublet Model

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    The radiative B ->\tau^+ \tau^- \gamma decay is investigated in the framework of the two Higgs doublet model . The dependence of the differential branching ratio on the photon energy and the branching ratio on the two Higgs doublet model parameters, m_{H^\pm} and \tan \beta, are studied. It is shown that there is an enhancement in the predictions of the two Higgs doublet model compared to the Standard model case. We also observe that contributions of neutral Higgs bosons to the decay are sizable when \tan\beta is large.Comment: 16 pages, 4 figure

    CP Asymmetry in Charged Higgs Decays in MSSM

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    We discuss and compare the charge-parity (CP) asymmetry in the charged Higgs boson decays H -> \bar{u}_i d_j for the second and third generation quarks in the minimal supersymmetric standard model. As part of the analysis, we derive some general analytical formulas for the imaginary parts of two-point and three-point scalar one-loop integrals and use them for calculating vectorial and tensorial type integrals needed for the problem under consideration. We find that, even though each decay mode has a potential to yield a CP asymmetry larger than 10%, further analysis based on the number of required charged Higgs events at colliders favors the \bar{t}b, \bar{c}b, and \bar{c}s channels, whose asymmetry could reach 10-15% in certain parts of the parameter space.Comment: 25 pages, 9 figures. Discussion about charged Higgs observability added, typos corrected, accepted for publication in PR

    Synthesis of Phosporus Included Multiwalled Carbon Nanotubes by Pyrolysis of Sucrose

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    Cataloged from PDF version of article.Multiwalled carbon nanotubes (MWCNT) were synthesized by a pyrolysis route which involves a dehydration step using phosphoric acid. The resultants were found to be mostly containing amorphous carbon with scattered MWCNTs using scanning electron and transmission electron microscopy techniques. These MWCNTs were smaller in size and limited in quantity compared to the ones synthesized using other common precursors. Energy dispersive X-ray and electron energy loss spectroscopy analysis indicated the presence of phosphorus both at the MWCNT sidewalls and in the catalyst particles encapsulated inside the MWCNTs. In addition, a comparative investigation for sulfur and phosphorus inclusion to the sidewalls of MWCNTs was carried out using density functional theory calculations. The results of the computational study showed that both phosphorus and sulfur atoms prefer to bind among themselves rather than adsorbing directly on carbon nanotubes (CNT). Furthermore, cluster calculations revealed that phosphorus atoms more likely form carbonaceous clusters which result in a decrease in the number of free carbon atoms that can be used for CNT formation. Therefore, we concluded that MWCNT growth might be hindered (promoted) in a phosphorus (sulfur) rich environment which results in needle like phosphorus containing MWCNTs

    B --> K^* \tau^+ \tau^- decay in the general two Higgs doublet model including the neutral Higgs boson effects

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    We study the CP violating asymmetry, the forward-backward asymmetry of the lepton pair and the CP asymmetry in the forward backward asymmetry for the exclusive decay $B --> K^* \tau^+ \tau^- in the general two Higgs doublet model including the neutral Higgs boson effects. We analyse the dependencies of these quantities on the model III parameters. We found that the physical parameters studied above are at the order of the magnitude 1% and neutral Higgs boson effects are detectable for large values of the coupling \bar{\xi}_{N,\tau\tau}^D.Comment: 20 pages, 11 Figure

    Flavor changing t -> c l_1^- l_2^+ decay in the general two Higgs doublet model

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    We study the flavor changing t-> c l_1^- l_2^+ decay in the framework of the general two Higgs doublet model, the so called model III. We predict the branching ratio for l_1=\tau, l_2=\mu at the order of magnitude of BR \sim 10^{-8}.Comment: 12 Pages, 5 Figure

    Perspective of turkish medicine students on cancer, cancer treatments, palliative care, and oncologists (ares study): A study of the palliative care working committee of the turkish oncology group (TOG)

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    Cancer is one of the most common causes of death all over the World (Rahib et al. in Cancer Res 74(11):2913–2921, 2014; Silbermann et al. in Ann Oncol 23(Suppl 3):iii15–iii28, 2012). It is crucial to diagnose this disease early by effective screening methods and also it is very important to acknowledge the community on various aspects of this disease such as the treatment methods and palliative care. Not only the oncologists but every medical doctor should be educated well in dealing with cancer patients. Previous studies suggested various opinions on the level of oncology education in medical schools (Pavlidis et al. in Ann Oncol 16(5):840–841, 2005). In this study, the perspectives of medical students on cancer, its treatment, palliative care, and the oncologists were analyzed in relation to their educational status. A multicenter survey analysis was performed on a total of 4224 medical school students that accepted to enter this study in Turkey. After the questions about the demographical characteristics of the students, their perspectives on the definition, diagnosis, screening, and treatment methods of cancer and their way of understanding metastatic disease as well as palliative care were analyzed. The questionnaire includes questions with answers and a scoring system of Likert type 5 (absolutely disagree = 1, completely agree = 5). In the last part of the questionnaire, there were some words to detect what the words “cancer” and “oncologist” meant for the students. The participant students were analyzed in two study groups; “group 1” (n = 1.255) were phases I and II students that had never attended an oncology lesson, and “group 2” (n = 2.969) were phases III to VI students that had attended oncology lessons in the medical school. SPSS v17 was used for the database and statistical analyses. A value of p < 0.05 was noted as statistically significant. Group 1 defined cancer as a contagious disease (p = 0.00025), they believed that early diagnosis was never possible (p = 0.042), all people with a diagnosis of cancer would certainly die (p = 0.044), and chemotherapy was not successful in a metastatic disease (p = 0.003) as compared to group 2. The rate of the students that believed gastric cancer screening was a part of the national screening policy was significantly more in group 1 than in group 2 (p = 0.00014). Group 2 had a higher anxiety level for themselves or their family members to become a cancer patient. Most of the students in both groups defined medical oncologists as warriors (57% in group 1 and 40% in group 2; p = 0.097), and cancer was reminding them of “death” (54% in group 1 and 48% in group 2; p = 0.102). This study suggested that oncology education was useful for the students’ understanding of cancer and related issues; however, the level of oncology education should be improved in medical schools in Turkey. This would be helpful for medical doctors to cope with many aspects of cancer as a major health care problem in this country. © 2018, American Association for Cancer Education

    The Casimir Force in a Lorentz Violating Theory

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    We study the effects of the minimal extension of the standard model including Lorentz violation on the Casimir force between two parallel conducting plates in vacuum. We provide explicit solutions for the electromagnetic field using scalar field analogy, for both the cases in which the Lorentz violating terms come from the CPT-even or CPT-odd terms. We also calculate the effects of the Lorentz violating terms for a fermion field between two parallel conducting plates and analyze the modifications of the Casimir force due to the modifications of the Dirac equation. In all cases under consideration, the standard formulas for the Casimir force are modified by either multiplicative or additive correction factors, the latter case exhibiting different dependence on the distance between the plates.Comment: 20 pages, no figures, references added, accepted for publication in Phys. Rev.

    SU(3)_flavor analysis of two-body weak decays of charmed baryons

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    We study two-body weak decays of charmed baryons \Lambda_c and \Xi_c into an octet or decuplet baryon and a pseudoscalar meson employing the SU(3) flavor symmetry. Using certain measured Cabibbo-favored modes, we fix the reduced amplitudes and predict the branching ratios of various decays of charmed baryons in the Cabibbo-enhanced, -suppressed and -doubly suppressed modes.Comment: 25 pages, No figure, Phys. Rev. D (to appear

    Mechanisms for the Negative Effects of Internalized HIV-Related Stigma on Antiretroviral Therapy Adherence in Women: The Mediating Roles of Social Isolation and Depression

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    Internalization of HIV-related stigma may inhibit a person's ability to manage HIV disease through adherence to treatment regimens. Studies, mainly with white men, have suggested an association between internalized stigma and suboptimal adherence to antiretroviral therapy (ART). However, there is a scarcity of research with women of different racial/ethnic backgrounds and on mediating mechanisms in the association between internalized stigma and ART adherence
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