439 research outputs found

    Strong decays of Tcc+T_{cc}^+ at NLO in an effective field theory

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    The Tcc+T_{cc}^+ exotic meson, discovered by the LHCb Collaboration in 2021, can be interpreted as a molecular state of D(∗)0D^{(*)0} and D(∗)+D^{(*)+} mesons. We compute next-to-leading-order (NLO) contributions to the strong decay of Tcc+T_{cc}^+ in an effective field theory for DD mesons and pions, considering contributions from one-pion exchange and final-state rescattering. Corrections to the total width, as well as the differential distribution in the invariant mass of the final-state DD meson pair are computed. The results remain in good agreement with LHCb experimental results when the NLO contributions are added. The leading uncertainties in the calculation come from terms which depend on the scattering length and effective range in DD meson scattering.Comment: 26 pages, 7 figure

    Polarized TMD fragmentation functions for J/ψJ/\psi production

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    We calculate the matching, at leading order, of the transverse momentum dependent fragmentation functions (TMDFFs) for light quarks and gluons fragmenting to a J/ψJ/\psi onto polarized non-relativistic QCD (NRQCD) TMDFFs. The NRQCD TMDFFs have an operator-product-expansion in terms of non-perturbative NRQCD production matrix elements. Using the results we obtain, we make predictions for the light quark fragmentation contribution to the production of polarized J/ψJ/\psi in semi-inclusive deep inelastic scattering (SIDIS) both for unpolarized and longitudinally polarized beams. These results are an important contribution to polarized J/ψJ/\psi production in SIDIS, and thus are needed for comparison with experiments at the future Electron-Ion Collider.Comment: 27 pages, 7 figure

    Polarized J/ψJ/\psi production in semi-inclusive DIS at large Q2Q^2: Comparing quark fragmentation and photon-gluon fusion

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    We compare the relative importance of different mechanisms for polarized J/ψJ/\psi production in semi-inclusive deep inelastic scattering processes at large Q2Q^2. The transverse momentum dependent (TMD) factorization framework and non-relativistic quantum chromodynamics are used to study the leading contributions from light quark fragmentation to polarized J/ψJ/\psi, and compared to direct production via photon-gluon fusion, which can proceed through color-singlet as well as color-octet mechanisms. We identify kinematic regimes where light quark fragmentation dominates, allowing for the extraction of the 3S1[8]^3S_1^{[8]} matrix element, as well as regimes where photon gluon fusion dominates, suggesting that the gluon TMD parton distribution function can be probed.Comment: 22 pages, 7 figure

    Student Physical Activity Patterns: Grade, Gender, and Activity Influences

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    The purpose of this study was to determine how physical education students\u27 cardiovascular responses as determined by mean heart rate, standard deviation of heart rate, and percentage of time in target heart rate zone varied according to student characteristics. Participants were 505 students in Grades 3 through 12. The Polar Accurex Plus heart rate telemetry system was used to measure the physiological load on the cardiovascular system. Three-way ANOVA results suggested that heart rate patterns in physical education varied according to gender, grade, and activity. For example, secondary school girls were more active in individual activities while secondary school boys were more active in team sport activities. Elementary students were the most active group and had the most variability in their heart rate patterns

    Cradle-To-Gate Life Cycle Assessment of Switchgrass Fuel Pellets Manufactured in the Southeastern United States

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    Developing renewable energy sources with low environmental impacts is becoming increasinglyimportant as concerns about consuming fossil fuel sources grow. Cultivating, harvesting, drying,and densifying raw biomass feedstocks into pellets for easy handling and transport is one step forward in this endeavor. However, the corresponding environmental performances must be quantified. This study presents cradle-to-gate life cycle inventory and impact assessment data for switchgrass fuel pellets potentially manufactured in the US Southeast. Because there are no current manufacturers of switchgrass pellets, inventory data were based on field trials of cultivation and harvest of switchgrass combined with a separate study of wood pelletization. Energy inputs for cultivation and harvest of switchgrass were collected by survey from farmers in Tennessee and represent the years 2008, 2009, and 2010. Data for pelletization were taken from a report on wood pellet manufacturing in the US Southeast. To produce 1.0 Mg of pellets that contain 18.0 GJ of potential bioenergy, 4.1 GJ of fossil energy inputs were required. Switchgrass crops require relatively little energy and inputs for the cultivation and harvest processes. The majority ofthe environmental burdens are associated with drying and pelletizing the raw material

    Subpromille Measurements and Calculations of CO (3–0) Overtone Line Intensities

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    Intensities of lines in the near-infrared second overtone band (3–0) of {12}^C{16}^O are measured and calculated to an unprecedented degree of precision and accuracy. Agreement between theory and experiment to better than 1‰ is demonstrated by results from two laboratories involving two independent absorption- and dispersion-based cavity-enhanced techniques. Similarly, independent Fourier transform spectroscopy measurements of stronger lines in this band yield mutual agreement and consistency with theory at the 1‰ level. This set of highly accurate intensities can provide an intrinsic reference for reducing biases in future measurements of spectroscopic peak areas
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