Using Machine Learning to Improve PDF Uncertainties

Parton Distribution Functions (PDFs) contribute significantly to the uncertainty on the determination of the top-quark pole mass and other precision measurements at the Large Hadron Collider (LHC). It is crucial to understand these uncertainties and reduce them to obtain the next generation of precision measurements at the LHC. The region of high momentum fraction offers an opportunity to make improvements to the PDFs. This study uses machine learning techniques in $t\bar{t}$ production to target this region of the PDF set and has potential to significantly reduce its uncertainty.Comment: Poster presentation at the 16th International Workshop on Top Quark Physics (Top2023), 24-29 September 202

Phytochemical, Analgesic And Acute Toxicity Studies Of Uncaria Attenuata (Korth.) Leaf Extract

Uncaria species from the family of Rubiaceae is a type of climbing vine found across Southeast Asia, East Asia, and South America. The Uncaria leaves and hooks (claw-like) traditionally been used to treat pain, neurological disorders, hypertension, stroke, rheumatism and other ailments. The study aimed to extract, isolate, and characterize the alkaloid constituents from the leaves of Uncaria attenuata (Korth.). In the present study, female Sprague Dawley rats were evaluated for acute toxicity for 14 days. In order to evaluate the antinociceptive activity of U. attenuata extracts and isolated alkaloid, a rat hot plate model was carried out. Two alkaloids have been successfully isolated and purified using chromatographic techniques: column chromatography, thin-layer chromatography and preparative thin-layer chromatography. Structure elucidation was performed using 1D NMR (1H, 13C, DEPT 90, DEPT 135), 2D NMR (COSY, HMBC, HSQC and NOESY), UV-Vis, FTIR, GC-MS and LC-MS. For the acute toxicity study, the rats were fed orally and employed in series of 175, 550 and 2000 mg/kg following the OECD 425 guideline. The rats were evaluated for physical abnormalities, infection, differences in posture and movement, and mortality. The relative organ weight of the rats’ harvested organs was calculated. Subsequently, for the analgesic study, the methanolic extract (250, 500 mg/kg), alkaloid extract (50, 100 mg/kg), and villocarine A (5, 10, 20 mg/kg) were given orally to the rats, respectively

Matter-wave interference and deflection of tripeptides decorated with fluorinated alkyl chains

Studies of neutral biomolecules in the gas phase allow for the study of molecular properties in the absence of solvent and charge effects, thus complementing spectroscopic and analytical methods in solution or in ion traps. Some properties, such as the static electronic susceptibility, are best accessed in experiments that act on the motion of the neutral molecules in an electric field. Here, we screen seven peptides for their thermal stability and electron impact ionizability. We identify two tripeptides as sufficiently volatile and thermostable to be evaporated and interfered in the long‐baseline universal matter‐wave interferometer. Monitoring the deflection of the interferometric molecular nanopattern in a tailored external electric field allows us to measure the static molecular susceptibility of Ala–Trp–Ala and Ala–Ala–Trp bearing fluorinated alkyl chains at C‐ and N‐termini

Experimental Results of Neutron Fluence Outside an Iron Shield in the Forward Direction

This work represents the first systematic study at a high energy accelerator of the depth dependence of neutron fluence in longitudinal shielding

Universal criterion for the breakup of invariant tori in dissipative systems

The transition from quasiperiodicity to chaos is studied in a two-dimensional dissipative map with the inverse golden mean rotation number. On the basis of a decimation scheme, it is argued that the (minimal) slope of the critical iterated circle map is proportional to the effective Jacobian determinant. Approaching the zero-Jacobian-determinant limit, the factor of proportion becomes a universal constant. Numerical investigation on the dissipative standard map suggests that this universal number could become observable in experiments. The decimation technique introduced in this paper is readily applicable also to the discrete quasiperiodic Schrodinger equation.Comment: 13 page

What is the Brightest Source for Dilepton Emissions at RHIC?

We calculate the dilepton emissions as the decay product of the charm and bottom quarks produced in heavy-ion collisions at RHIC energy. We take into account the next-to-leading-order radiative corrections in perturbative QCD to the heavy quark production from both an initial hard parton-parton scattering and an ideal quark-gluon plasma. We find that the thermal charm decay dominates the dilepton production in the low dilepton mass region ($<2$ GeV), while the heavy quark production from the initial scattering takes over the intermediate and high mass regions ($> 2$ GeV). Our result also indicates the importance of the bottom quark in the high mass region ($>4$ GeV ) due to its large mass and cascade decay. If the initial scattering produced charm suffers a significant energy loss due to the secondary interaction, the bottom decay constitutes the major background for the thermal dileptons.Comment: 12 pages in RevTeX, 3 epsf figures embedde

The Professional Solution to the College Bubble

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Counter-propagating radiative shock experiments on the Orion laser and the formation of radiative precursors

We present results from new experiments to study the dynamics of radiative shocks, reverse shocks and radiative precursors. Laser ablation of a solid piston by the Orion high-power laser at AWE Aldermaston UK was used to drive radiative shocks into a gas cell initially pressurised between $0.1$ and $1.0 \ bar with different noble gases. Shocks propagated at {80 \pm 10 \ km/s} and experienced strong radiative cooling resulting in post-shock compressions of { \times 25 \pm 2}. A combination of X-ray backlighting, optical self-emission streak imaging and interferometry (multi-frame and streak imaging) were used to simultaneously study both the shock front and the radiative precursor. These experiments present a new configuration to produce counter-propagating radiative shocks, allowing for the study of reverse shocks and providing a unique platform for numerical validation. In addition, the radiative shocks were able to expand freely into a large gas volume without being confined by the walls of the gas cell. This allows for 3-D effects of the shocks to be studied which, in principle, could lead to a more direct comparison to astrophysical phenomena. By maintaining a constant mass density between different gas fills the shocks evolved with similar hydrodynamics but the radiative precursor was found to extend significantly further in higher atomic number gases (\sim$$4$ times further in xenon than neon). Finally, 1-D and 2-D radiative-hydrodynamic simulations are presented showing good agreement with the experimental data.Comment: HEDLA 2016 conference proceeding