We analyze the recent LHCb measurement of the distribution of the fraction of the transverse momentum, z(J/ψ), carried by the J/ψ within a jet. LHCb data is compared to analytic calculations using the fragmenting jet function (FJF) formalism for studying J/ψ in jets. Logarithms in the FJFs are resummed using DGLAP evolution. We also convolve hard QCD partonic cross sections, showered with PYTHIA, with leading order Non-Relativistic Quantum Chromodynamics (NRQCD) fragmentation functions and obtain consistent results. Both approaches use Madgraph to calculate the hard process that creates the jet initiating parton. These calculations give reasonable agreement with the z(J/ψ) distribution that was shown to be poorly described by default PYTHIA simulations in the LHCb paper. We compare our predictions for the J/ψ distribution using various extractions of nonperturbative NRQCD long-distance matrix elements (LDMEs) in the literature. NRQCD calculations agree with LHCb data better than default PYTHIA regardless of which fit to the LDMEs is used. LDMEs from fits that focus exclusively on high transverse momentum data from colliders are in good agreement with the LHCb measurement.The production of quarkonium is a challenging test of Quantum Chromodynamics due to the mutiple length scales involved. The LHCb collaboration [1] published the first study of J/ψ produced within jets. The distribution of the fraction of the jet's transverse momentum, p T , carried by the J/ψ, z(J/ψ), was found to disagree significantly with predictions from the PYTHIA monte carlo [2, 3] using leading order calculations of J/ψ production in the Non-Relativistic Quantum Chromodynamics (NRQCD) factorization formalism [4]. This letter is provides improved theoretical calculations of the z(J/ψ) distribution and to discuss the implications of the LHCb results for the NRQCD factorization formalism.Production of quarkonium in hadron colliders has been the subject of experimental and theoretical studies for decades. The problem is challenging because it involves several disparate scales. These include p T , which can be much larger than the mass of the bound state, ≈ 2m Q , where m Q is the mass of the heavy quark, as well as scales that are much smaller: the relative momenta, m Q v (v is the typical velocity of the heavy quarks in the bound state), the kinetic energy, m Q v 2 , and the nonperturbative scale Λ QCD .The most common approach to calculating quarkonium production is the NRQCD factorization formalism [4]. In this formalism, the cross section for J/ψ in a pp collision is written aswhere dσ[pp → cc(n)X] is the short distance cross section for producing the cc pair in a state n with definite color and angular momentum quantum numbers and O J/ψ (n) is a long distance matrix element (LDME) that describes the nonperturbative transition of the cc pair in the state n into a final state containing J/ψ. X denotes other possible particles in the final state. The quantum numbers n will be denoted 2S+1 L [i]J where the notation for angular momentum is st...

We introduce the transverse momentum dependent fragmenting jet function (TMDFJF), which appears in factorization theorems for cross sections for jets with an identified hadron. These are functions of z, the hadron's longitudinal momentum fraction, and transverse momentum, p ⊥ , relative to the jet axis. In the framework of Soft-Collinear Effective Theory (SCET) we derive the TMDFJF from both a factorized SCET cross section and the TMD fragmentation function defined in the literature. The TMDFJFs are factorized into distinct collinear and soft-collinear modes by matching onto SCET + . As TMD calculations contain rapidity divergences, both the renormalization group (RG) and rapidity renormalization group (RRG) must be used to provide resummed calculations with next-to-leading-logarithm prime (NLL') accuracy. We apply our formalism to the production of J/ψ within jets initiated by gluons. In this case the TMDFJF can be calculated in terms of NRQCD (Non-relativistic quantum chromodynamics) fragmentation functions. We find that when the J/ψ carries a significant fraction of the jet energy, the p T and z distributions differ for different NRQCD production mechanisms. Another observable with discriminating power is the average angle that the J/ψ makes with the jet axis.

We study jets with identified hadrons in which a family of jet-shape variables called angularities are measured, extending the concept of fragmenting jet functions (FJFs) to these observables. FJFs determine the fraction of energy, z, carried by an identified hadron in a jet with angularity, τ a . The FJFs are convolutions of fragmentation functions (FFs), evolved to the jet energy scale, with perturbatively calculable matching coefficients. Renormalization group equations are used to provide resummed calculations with next-toleading logarithm prime (NLL') accuracy. We apply this formalism to two-jet events in e + e − collisions with B mesons in the jets, and three-jet events in which a J/ψ is produced in the gluon jet. In the case of B mesons, we use a phenomenological FF extracted from e + e − collisions at the Z 0 pole evaluated at the scale µ = m b . For events with J/ψ, the FF can be evaluated in terms of Non-Relativistic QCD (NRQCD) matrix elements at the scale µ = 2m c . The z and τ a distributions from our NLL' calculations are compared with predictions from monte carlo event generators. While we find consistency between the predictions for B mesons and the J/ψ distributions in τ a , we find the z distributions for J/ψ differ significantly. We describe an attempt to merge PYTHIA showers with NRQCD FFs that gives good agreement with NLL' calculations of the z distributions.

The ability of scientists to effectively communicate their research, and scientific ideas in general, with a variety of audiences is critical in both academic and non-academic careers. There is currently a dearth of formal and informal science communication training opportunities for graduate students in science, technology, engineering, and mathematics (STEM) fields. This curriculum paper introduces ComSciCon-Triangle, a graduate student–organized science communication workshop for graduate students in STEM at research universities in the Raleigh-Durham, North Carolina, region. Started in 2015, this annual workshop aims to empower graduate students to be more engaged in communicating their research with the public as well as with fellow scientists. Each workshop consists of interactive panel discussions with invited science communicators (science writers, academics, filmmakers, etc.), informal networking opportunities with invited guests and other attendees, and hands-on sessions for improving oral and written communication skills. Analyzing pre- and post-survey data from all ComSciCon-Triangle attendees from 2015 to 2017, we find that workshop attendees feel significantly more confident in their ability to communicate scientific ideas with both the general public and with other scientists, and more confident submitting a written piece to a popular science publication or journal. We discuss how ComSciCon-Triangle serves as a model for local science communication workshops “for graduate students, organized by graduate students.”