174 research outputs found

    HOMFLY and superpolynomials for figure eight knot in all symmetric and antisymmetric representations

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    Explicit answer is given for the HOMFLY polynomial of the figure eight knot 414_1 in arbitrary symmetric representation R=[p]. It generalizes the old answers for p=1 and 2 and the recently derived results for p=3,4, which are fully consistent with the Ooguri-Vafa conjecture. The answer can be considered as a quantization of the \sigma_R = \sigma_{[1]}^{|R|} identity for the "special" polynomials (they define the leading asymptotics of HOMFLY at q=1), and arises in a form, convenient for comparison with the representation of the Jones polynomials as sums of dilogarithm ratios. In particular, we construct a difference equation ("non-commutative A-polynomial") in the representation variable p. Simple symmetry transformation provides also a formula for arbitrary antisymmetric (fundamental) representation R=[1^p], which also passes some obvious checks. Also straightforward is a deformation from HOMFLY to superpolynomials. Further generalizations seem possible to arbitrary Young diagrams R, but these expressions are harder to test because of the lack of alternative results, even partial.Comment: 14 page

    The Physics of the B Factories

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    This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

    Measurement of ϒ production in pp collisions at √s = 2.76 TeV

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    The production of ϒ(1S), ϒ(2S) and ϒ(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb−1 collected in proton–proton collisions at a centre-of-mass energy of √s = 2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ϒ transverse momentum and rapidity, over the ranges pT < 15 GeV/c and 2.0 < y < 4.5. The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be σ (pp → ϒ(1S)X) × B ϒ(1S)→Ό+Ό− = 1.111 ± 0.043 ± 0.044 nb, σ (pp → ϒ(2S)X) × B ϒ(2S)→Ό+Ό− = 0.264 ± 0.023 ± 0.011 nb, σ (pp → ϒ(3S)X) × B ϒ(3S)→Ό+Ό− = 0.159 ± 0.020 ± 0.007 nb, where the first uncertainty is statistical and the second systematic

    EuFe2_2As2_2 under high pressure: an antiferromagnetic bulk superconductor

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    We report the ac magnetic susceptibility χac\chi_{ac} and resistivity ρ\rho measurements of EuFe2_2As2_2 under high pressure PP. By observing nearly 100% superconducting shielding and zero resistivity at PP = 28 kbar, we establish that PP-induced superconductivity occurs at Tc∌T_c \sim~30 K in EuFe2_2As2_2. ρ\rho shows an anomalous nearly linear temperature dependence from room temperature down to TcT_c at the same PP. χac\chi_{ac} indicates that an antiferromagnetic order of Eu2+^{2+} moments with TN∌T_N \sim~20 K persists in the superconducting phase. The temperature dependence of the upper critical field is also determined.Comment: To appear in J. Phys. Soc. Jpn., Vol. 78 No.

    withdrawn 2017 hrs ehra ecas aphrs solaece expert consensus statement on catheter and surgical ablation of atrial fibrillation

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    Socialization, legitimation and the transfer of biomedical knowledge to low- and middle-income countries: analyzing the case of emergency medicine in India

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    BACKGROUND: Medical specialization is a key feature of biomedicine, and is a growing, but weakly understood aspect of health systems in many low- and middle-income countries (LMICs), including India. Emergency medicine is an example of a medical specialty that has been promoted in India by several high-income country stakeholders, including the Indian diaspora, through transnational and institutional partnerships. Despite the rapid evolution of emergency medicine in comparison to other specialties, this specialty has seen fragmentation in the stakeholder network and divergent training and policy objectives. Few empirical studies have examined the influence of stakeholders from high-income countries broadly, or of diasporas specifically, in transferring knowledge of medical specialization to LMICs. Using the concepts of socialization and legitimation, our goal is to examine the transfer of medical knowledge from high-income countries to LMICs through domestic, diasporic and foreign stakeholders, and the perceived impact of this knowledge on shaping health priorities in India. METHODS: This analysis was conducted as part of a broader study on the development of emergency medicine in India. We designed a qualitative case study focused on the early 1990s until 2015, analyzing data from in-depth interviewing (n = 87), document review (n = 248), and non-participant observation of conferences and meetings (n = 6). RESULTS: From the early 1990s, domestic stakeholders with exposure to emergency medicine in high-income countries began to establish Emergency Departments and initiate specialist training in the field. Their efforts were amplified by the active legitimation of emergency medicine by diasporic and foreign stakeholders, who formed transnational partnerships with domestic stakeholders and organized conferences, training programs and other activities to promote the field in India. However, despite a broad commitment to expanding specialist training, the network of domestic, diasporic and foreign stakeholders was highly fragmented, resulting in myriad unstandardized postgraduate training programs and duplicative policy agendas. Further, the focus in this time period was largely on training specialists, resulting in more emphasis on a medicalized, tertiary-level form of care. CONCLUSIONS: This analysis reveals the complexities of the roles and dynamics of domestic, diasporic and foreign stakeholders in the evolution of emergency medicine in India. More research and critical analyses are required to explore the transfer of medical knowledge, such as other medical specialties, models of clinical care, and medical technologies, from high-income countries to India

    Study of D-(*())(+)(sJ) mesons decaying to D*K-+(S)0 and D*K-0(+) final states

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    A search is performed for DsJ(∗)+D^{(*)+}_{sJ} mesons in the reactions pp→D∗+KS0Xpp \to D^{*+} K^0_{\rm S} X and pp→D∗0K+Xpp \to D^{*0} K^+ X using data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb detector. For the D∗+KS0D^{*+} K^0_{\rm S} final state, the decays D∗+→D0π+D^{*+} \to D^0 \pi^+ with D0→K−π+D^0 \to K^- \pi^+ and D0→K−π+π+π−D^0 \to K^- \pi^+ \pi^+ \pi^- are used. For D∗0K+D^{*0} K^+, the decay D∗0→D0π0D^{*0} \to D^0 \pi^0 with D0→K−π+D^0 \to K^- \pi^+ is used. A prominent Ds1(2536)+D_{s1}(2536)^+ signal is observed in both D∗+KS0D^{*+} K^0_{\rm S} and D∗0K+D^{*0} K^+ final states. The resonances Ds1∗(2700)+D^*_{s1}(2700)^+ and Ds3∗(2860)+D^*_{s3}(2860)^+ are also observed, yielding information on their properties, including spin-parity assignments. The decay Ds2∗(2573)+→D∗+KS0D^*_{s2}(2573)^+ \to D^{*+} K^0_{\rm S} is observed for the first time, at a significance of 6.9 σ\sigma, and its branching fraction relative to the Ds2∗(2573)+→D+KS0D^*_{s2}(2573)^+ \to D^+ K^0_{\rm S} decay mode is measured

    Search for Violations of Lorentz Invariance and CPT Symmetry in B-(s)(0) Mixing

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    Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B^{0} mixing and in B_{s}^{0} mixing. Samples of B^{0}→J/ψK_{S}^{0} and B_{s}^{0}→J/ψK^{+}K^{-} decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3  fb^{-1}. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and CPT symmetry. Results are expressed in terms of the standard model extension parameter Δa_{ÎŒ} with precisions of O(10^{-15}) and O(10^{-14})  GeV for the B^{0} and B_{s}^{0} systems, respectively. With no assumption on Lorentz (non)invariance, the CPT-violating parameter z in the B_{s}^{0} system is measured for the first time and found to be Re(z)=-0.022±0.033±0.005 and Im(z)=0.004±0.011±0.002, where the first uncertainties are statistical and the second systematic

    Study of the doubly charmed tetraquark T+cc

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    Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed
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