Experimental methods in top physics

Top quark physics at the Tevatron has inspired particle physicists to develop new methods of understanding hadron collider data. From sophisticated one-dimensional fitting techniques to multidimensional neural networks, the top quark physics program has innovated many techniques which at this time are used extensively in the high-pT program at the Tevatron and LHC

Effects of an Interactive, Literacy-Rich Environment on the Social, Language, Cognitive, and Literacy Development of Young Children with and without Special Needs

The purpose of this study is twofold: to identify play and literacy practices that are useful in an inclusive early childhood classroom and to demonstrate how these practices contribute to the development of children with and without disabilities. Play and literacy teaching practices are documented in this study of four preschool children. Two of the children have typical development patterns and two have mild to moderate special needs

ABCNet: An attention-based method for particle tagging

In high energy physics, graph-based implementations have the advantage of treating the input data sets in a similar way as they are collected by collider experiments. To expand on this concept, we propose a graph neural network enhanced by attention mechanisms called ABCNet. To exemplify the advantages and flexibility of treating collider data as a point cloud, two physically motivated problems are investigated: quark-gluon discrimination and pileup reduction. The former is an event-by-event classification while the latter requires each reconstructed particle to receive a classification score. For both tasks ABCNet shows an improved performance compared to other algorithms available.Comment: 13 pages, 5 figure

Point Cloud Transformers applied to Collider Physics

Methods for processing point cloud information have seen a great success in collider physics applications. One recent breakthrough in machine learning is the usage of Transformer networks to learn semantic relationships between sequences in language processing. In this work, we apply a modified Transformer network called Point Cloud Transformer as a method to incorporate the advantages of the Transformer architecture to an unordered set of particles resulting from collision events. To compare the performance with other strategies, we study jet-tagging applications for highly-boosted particles.Comment: 12 pages, 3 figure

Measurement of the cross section for direct-photon production in association with a heavy quark in pp¯ collisions at s√ = 1.96 TeV

We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of s√=1.96  TeV proton-antiproton collisions corresponding to 9.1  fb−1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yγ|20  GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions

Anesthetic Considerations for Cervical Fusion Surgery in Advanced Rheumatoid Arthritis and Severe Pulmonary Hypertension

67 year-old female with a history of rheumatoid arthritis (RA) and pulmonary hypertension (PH) presented for urgent C4-C5 anterior diskectomy and C3-C6 posterior fusion for cervical subluxation. C-spine MRI showed severe cord impingement. The patient was brought to the operating room with minimal sedation to avoid exacerbation of PH. The radial artery was inaccessible due to flexion deformities, thus a brachial arterial line was placed. Awake fiberoptic intubation was performed with dexmedetomidine, followed by demonstration of movement of all four extremities. The anesthesia was maintained with dexmedetomidine and desflurane. The anterior and posterior portions of the procedure were performed uneventfully with no change in baseline somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP). The patient was extubated at the end of the case and was followed in the intensive care unit (ICU) and was discharged to rehabilitation in good condition

Indirect measurement of sin⁡2θW\sin^2 \theta_W (or MWM_W) using μ+μ−\mu^+\mu^- pairs from γ∗/Z\gamma^*/Z bosons produced in ppˉp\bar{p} collisions at a center-of-momentum energy of 1.96 TeV

Drell-Yan lepton pairs are produced in the process $p\bar{p} \rightarrow \mu^+\mu^- + X$ through an intermediate $\gamma^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribution of the $\mu^-$ as a function of the invariant mass of the $\mu^+\mu^-$ pair is used to obtain the effective leptonic determination $\sin^2 \theta^{lept}_{eff}$ of the electroweak-mixing parameter $\sin^2 \theta_W$, from which the value of $\sin^2 \theta_W$ is derived assuming the standard model. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.2 fb-1 of integrated luminosity from $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of $\sin^2 \theta^{lept}_{eff}$ is found to be 0.2315 +- 0.0010, where statistical and systematic uncertainties are combined in quadrature. When interpreted within the context of the standard model using the on-shell renormalization scheme, where $\sin^2 \theta_W = 1 - M_W^2/M_Z^2$, the measurement yields $\sin^2 \theta_W$ = 0.2233 +- 0.0009, or equivalently a W-boson mass of 80.365 +- 0.047 GeV/c^2. The value of the W-boson mass is in agreement with previous determinations in electron-positron collisions and at the Tevatron collider

Measurement of the charge asymmetry of electrons from the decays of W bosons produced in pp‾p\overline{p} collisions at s\sqrt{s} = 1.96 TeV

At the Fermilab Tevatron proton-antiproton (p¯p) collider, high-mass electron-neutrino (eν) pairs are produced predominantly in the process p¯p→W(→eν)+X. The asymmetry of the electron and positron yield as a function of their pseudorapidity constrain the slope of the ratio of the u- to d-quark parton distributions versus the fraction of the proton momentum carried by the quarks. This paper reports on the measurement of the electron-charge asymmetry using the full data set recorded by the Collider Detector at Fermilab in 2001–2011 and corresponding to 9.1  fb−1 of integrated luminosity. The measurement significantly improves the precision of the Tevatron constraints on the parton-distribution functions of the proton. Numerical tables of the measurement are provided

Forward-backward asymmetry of Drell–Yan lepton pairs in pp collisions at s\sqrt{s} = 8 TeV

A measurement of the forward-backward asymmetry AFB of oppositely charged lepton pairs (μμ and ee) produced via Z/γ∗ boson exchange in pp collisions at $\sqrt{s}$ = 8 TeV is presented. The data sample corresponds to an integrated luminosity of 19.7 fb$^{−1}$ collected with the CMS detector at the LHC. The measurement of $A_{FB}$ is performed for dilepton masses between 40 GeV and 2 TeV and for dilepton rapidity up to 5. The $A_{FB}$ measurements as a function of dilepton mass and rapidity are compared with the standard model predictions