439 research outputs found
Strong decays of at NLO in an effective field theory
The exotic meson, discovered by the LHCb Collaboration in 2021,
can be interpreted as a molecular state of and mesons. We
compute next-to-leading-order (NLO) contributions to the strong decay of
in an effective field theory for 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 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 meson scattering.Comment: 26 pages, 7 figure
Polarized TMD fragmentation functions for production
We calculate the matching, at leading order, of the transverse momentum
dependent fragmentation functions (TMDFFs) for light quarks and gluons
fragmenting to a 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 in semi-inclusive deep inelastic scattering
(SIDIS) both for unpolarized and longitudinally polarized beams. These results
are an important contribution to polarized production in SIDIS, and
thus are needed for comparison with experiments at the future Electron-Ion
Collider.Comment: 27 pages, 7 figure
Polarized production in semi-inclusive DIS at large : Comparing quark fragmentation and photon-gluon fusion
We compare the relative importance of different mechanisms for polarized
production in semi-inclusive deep inelastic scattering processes at
large . 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 , 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 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
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
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
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Photoplethysmography for Quantitative Assessment of Sympathetic Nerve Activity (SNA) During Cold Stress
The differences in the degree of sympathetic nerve activity (SNA) over cutaneous blood vessels, although known to be more prominent in the periphery than the core vasculature, has not been thoroughly investigated quantitatively. Hence, two studies were carried out to investigate the differences in SNA between the periphery and the core during the cold pressor test (CPT) (right-hand immersion in ice water) and cold exposure (whole body exposed to cold air) using photoplethysmography (PPG). Two methods utilizing PPG, namely differential multi-site PTT measurements and low-frequency spectral analysis were explored for quantitative determination of SNA. Each study involved 12 healthy volunteers, and PPG signals were acquired from the right index finger (RIF), left index finger (LIF) (periphery) and the ear canal (core). During CPT, Pulse Transit Time (PTT) was measured to the respective locations and the mean percentage change in PTT during ice immersion at each location was used as an indicator for the extent of SNA. During cold exposure, the low-frequency spectral analysis was performed on the acquired raw PPGs to extract the power of the sympathetic [low-frequency (LF): 0.04–0.15 Hz] and parasympathetic components [high-frequency (HF): 0.15–0.4 Hz]. The ratio of LF/HF components was then used to quantify the differences in the influence of SNA on the peripheral and core circulation. PTT measured from the EC, and the LIF has dropped by 5 and 7%, respectively during ice immersion. The RIF PTT, on the other hand, has dropped significantly (P < 0.05) by 12%. During the cold exposure, the LF/HF power ratio at the finger has increased to 86.4 during the cold exposure from 19.2 at the baseline (statistically significant P = 0.002). While the ear canal LF/HF ratio has decreased to 1.38 during the cold exposure from 1.62 at baseline (P = 0.781). From these observations, it is evident that differential PTT measurements or low-frequency analysis can be used to quantify SNA. The results also demonstrate the effectiveness of the central auto-regulation during both short and long-term stress stimulus as compared to the periphery
The Low Basicity of Phosphabenzenes: First Examples of Protonation, Alkylation, and Silylation Reactions
The Low Basicity of Phosphabenzenes: First Examples of Protonation, Alkylation, and Silylation Reactions
Subpromille Measurements and Calculations of CO (3–0) Overtone Line Intensities
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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