We introduce the Centauric 1-jettiness, τ_1^C, a generalized event shape for Deep Inelastic Scattering (DIS) with adjustable beam and jet reference vectors and thus beam and jet regions. We demonstrate that a specific choice of weights allows this observable to exactly reproduce the geometric boundaries of the Centauro jet algorithm in the Breit frame. Within the framework of Soft-Collinear Effective Theory (SCET), we derive a factorized cross section in the small-τ_1^C region in terms of known perturbative ingredients. This allows the resummation of large logarithms to N^3LL accuracy, which we then match to fixed-order NLO QCD (𝒪(α_s^2)) predictions from . We establish that the soft measurement reduces to a rescaled hemisphere measurement, placing Centauric 1-jettiness in the same universality class, for the leading non-perturbative corrections, as DIS thrust and jet mass. As a consequence, the leading non-perturbative shift depends on the same universal first-moment-shift parameter Ω_1 and scales exactly as 1/R with the jet radius, thanks to the boost invariance of the Centauro algorithm along the photon axis in the Breit frame, a scaling that we test using Pythia simulations. These results open new strategies for determining the strong coupling from DIS event shapes, with R providing a handle to break the degeneracy between α_s and the universal non-perturbative shift parameter Ω_1.

Diffraction is characterized by forward scattering and a large rapidity gap. Ordinary hard scattering also produces gapped events and presents a significant background to identification of diffractively produced events. We present a fully differential factorization of gapped hard ep scattering. We find that the unpolarized azimuthally-dependent structure functions F_3,4^ gap and the longitudinal F_L^ gap vanish at leading power for hard scattering. Azimuthal dependence is thus a pure diffractive signature. This is borne out in Monte Carlo simulations.

We present predictions for the DIS 1-jettiness event shape $\tau_1^b$, or DIS thrust, using the framework of Soft Collinear Effective Theory (SCET) for factorization, resummation of large logarithms, and rigorous treatment of nonperturbative power corrections, matched to fixed-order QCD away from the resummation region. Our predictions reach next-to-next-to-next-to-leading-logarithmic (N$^3$LL) accuracy in resummed perturbation theory, matched to $O(\alpha_s^2)$ fixed-order QCD calculations obtained using the program NLOJet++. We include a rigorous treatment of hadronization corrections, which are universal across different event shapes and kinematic variables $x$ and $Q$ at leading power, and supplement them with a systematic scheme to remove $O(\Lambda_\textrm{QCD})$ renormalon ambiguities in their definition. The framework of SCET allows us to connect smoothly the nonperturbative, resummation, and fixed-order regions, whose relative importance varies with $x$ and $Q$, and to rigorously estimate theoretical uncertainties, across a broad range of $x$ and $Q$ covering existing experimental results from HERA as well as expected new measurements from the upcoming Electron-Ion-Collider (EIC). Our predictions will serve as an important benchmark for the EIC program, enabling the precise determination of the QCD strong coupling $\alpha_s$ and the universal nonperturbative first moment parameter $\Omega_1$.

We study the role of renormalon cancellation schemes and perturbative scale choices in extractions of the strong coupling constant $\alpha_s(m_Z)$ and the leading non-perturbative shift parameter $\Omega_1$ from resummed predictions of the $e^+e^-$ event shape thrust. We calculate the thrust distribution to N$^{3}$LL$^\prime$ resummed accuracy in Soft-Collinear Effective Theory (SCET) matched to the fixed-order $\mathcal{O}(\alpha_s^2)$ prediction, and perform a new high-statistics computation of the $\mathcal{O}(\alpha_s^3)$ matching in EERAD3, although we do not include the latter in our final $\alpha_s$ fits due to some observed systematics that require further investigation. We are primarily interested in testing the phenomenological impact sourced from varying amongst three renormalon cancellation schemes and two sets of perturbative scale profile choices. We then perform a global fit to available data spanning center-of-mass energies between 35-207 GeV in each scenario. Relevant subsets of our results are consistent with prior SCET-based extractions of $\alpha_s(m_Z)$, but we are also led to a number of novel observations. Notably, we find that the combined effect of altering the renormalon cancellation scheme and profile parameters can lead to few-percent-level impacts on the extracted values in the $\alpha_s-\Omega_1$ plane, indicating a potentially important systematic theory uncertainty that should be accounted for. We also observe that fits performed over windows dominated by dijet events are typically of a higher quality than those that extend into the far tails of the distributions, possibly motivating future fits focused more heavily in this region. Finally, we discuss how different estimates of the three-loop soft matching coefficient $c_{\tilde{S}}^3$ can also lead to measurable changes in the fitted $\lbrace \alpha_s, \Omega_1 \rbrace$ values.

Outline of the talk 3 Event shapes and the strong coupling EFT, factorization, resummation of perturbative logs Nonperturbative corrections, gaps and renormalon subtraction schemes Effects of perturbative and nonperturbative scale & scheme choices on fits for In a nutshell: some of these choices have a few % effect on the tails of event shape distributions and the values of extracted by comparing them to data Motivations for more data and more theory work on more event shapes α s α

We reassess the theoretical uncertainties of strong-coupling determinations from a global fit to the $e^+ e^-$ thrust data, focusing in particular on the scheme dependence associated with the applied renormalon-cancellation prescription and on the choice of scale parameters that are used to estimate higher-order perturbative corrections in all sectors of the calculation.

Abstract We propose to utilize angularity distributions in Higgs boson decay to probe light quark Yukawa couplings at e+e− colliders. Angularities τa are a class of 2-jet event shapes with variable and tunable sensitivity to the distribution of radiation in hadronic jets in the final state. Using soft-collinear effective theory (SCET), we present a prediction of angularity distributions from Higgs decaying to quark and gluon states at e+e− colliders to NNLL + 𝒪(αs) accuracy. Due to the different color structures in quark and gluon jets, the angularity distributions from H → $$q\overline{q }$$ and H → gg show different behaviors and can be used to constrain the light quark Yukawa couplings. We show that the upper limit of light quark Yukawa couplings could be probed to the level of ~ 15% of the bottom quark Yukawa coupling in the Standard Model in a conservative analysis window far away from nonperturbative effects and other uncertainties; the limit can be pushed to ≲ 7 – 9% with better control of the nonperturbative effects especially on gluon angularity distributions and/or with multiple angularities.

This handbook provides a comprehensive review of transverse-momentum-dependent parton distribution functions and fragmentation functions, commonly referred to as transverse momentum distributions (TMDs). TMDs describe the distribution of partons inside the proton and other hadrons with respect to both their longitudinal and transverse momenta. They provide unique insight into the internal momentum and spin structure of hadrons, and are a key ingredient in the description of many collider physics cross sections. Understanding TMDs requires a combination of theoretical techniques from quantum field theory, nonperturbative calculations using lattice QCD, and phenomenological analysis of experimental data. The handbook covers a wide range of topics, from theoretical foundations to experimental analyses, as well as recent developments and future directions. It is intended to provide an essential reference for researchers and graduate students interested in understanding the structure of hadrons and the dynamics of partons in high energy collisions.

We outline the physics opportunities provided by the Electron Ion Collider (EIC). These include the study of the parton structure of the nucleon and nuclei, the onset of gluon saturation, the production of jets and heavy flavor, hadron spectroscopy and tests of fundamental symmetries. We review the present status and future challenges in EIC theory that have to be addressed in order to realize this ambitious and impactful physics program, including how to engage a diverse and inclusive workforce. In order to address these many-fold challenges, we propose a coordinated effort involving theory groups with differing expertise is needed. We discuss the scientific goals and scope of such an EIC Theory Alliance.

We present a comprehensive analysis of the potential sensitivity of the Electron-Ion Collider (EIC) to charged lepton flavor violation (CLFV) in the channel $ep\to \tau X$, within the model-independent framework of the Standard Model Effective Field Theory (SMEFT). We compute the relevant cross sections to leading order in QCD and electroweak corrections and perform simulations of signal and SM background events in various $\tau$ decay channels, suggesting simple cuts to enhance the associated estimated efficiencies. To assess the discovery potential of the EIC in $\tau$-$e$ transitions, we study the sensitivity of other probes of this physics across a broad range of energy scales, from $pp \to e \tau X$ at the Large Hadron Collider to decays of $B$ mesons and $\tau$ leptons, such as $\tau \to e \gamma$, $\tau \to e \ell^+ \ell^-$, and crucially the hadronic modes $\tau \to e Y$ with $Y \in \{ \pi, K, \pi \pi, K \pi, ...\}$. We find that electroweak dipole and four-fermion semi-leptonic operators involving light quarks are already strongly constrained by $\tau$ decays, while operators involving the $c$ and $b$ quarks present more promising discovery potential for the EIC. An analysis of three models of leptoquarks confirms the expectations based on the SMEFT results. We also identify future directions needed to maximize the reach of the EIC in CLFV searches: these include an optimization of the $\tau$ tagger in hadronic channels, an exploration of background suppression through tagging $b$ and $c$ jets in the final state, and a global fit by turning on all SMEFT couplings, which will likely reveal new discovery windows for the EIC.

the Los Alamos researchers developed a computer code, called BURST, that can simulate conditions during the first few minutes of cosmological evolution.

We develop an effective field theory (EFT) framework to perform an analytic calculation for energy correlator observables computed on groomed heavy-quark jets. A soft-drop grooming algorithm is applied to a jet initiated by a massive quark to minimize soft contamination effects such as pile-up and multi-parton interactions. We specifically consider the two-particle energy correlator as an initial application of this EFT framework to compute heavy quark jet substructure. We find that there are different regimes for the event shapes, depending on the size of the measured correlator observable, that require the use of different EFT formulations, in which the quark mass and grooming parameters may be relevant or not. We use the EFT to resum large logarithms in the energy correlator observable in terms of the momentum of a reconstructed heavy hadron to NLL′ accuracy and subsequently match it to a full QCD $$ \mathcal{O} $$ (αs) cross section, which we also compute. We compare our predictions to simulations in Pythia for e+e− collisions. We find a good agreement with partonic simulations, as well as hadronic ones with an appropriate shape function used to describe nonperturbative effects and the heavy quark hadron decay turned off. We also predict the scaling behavior for the leading nonperturbative power correction due to hadronization. Consequently, we can give a prediction for the energy correlator distribution at the level of the reconstructed heavy hadron. This work provides a general framework for the analysis of heavy quark jet substructure observables.

We present predictions for the e+e− event shape angularities at NNLL′ resummed and \( \mathcal{O}\left({\alpha}_s^2\right) \) matched accuracy and compare them to LEP data at center-of-mass energies Q = 91.2 GeV and Q = 197 GeV. We perform the resummation within the framework of Soft-Collinear Effective Theory, and make use of recent results for the two-loop angularity soft function. We determine the remaining NNLL′ and \( \mathcal{O}\left({\alpha}_s^2\right) \) ingredients from a fit to the EVENT2 generator, and implement a shape function with a renormalon-free gap parameter to model non-perturbative effects. Using values of the strong coupling αs(mZ) and the universal non-perturbative shift parameter Ω1 that are consistent with those obtained in previous fits to the thrust and C-parameter distributions, we find excellent agreement between our predictions and the LEP data for all angularities with a ∈ [−1, 0.5]. This provides a robust test of the predictions of QCD, factorization, and the universal scaling of the non-perturbative shift across different angularities. Promisingly, our results indicate that current degeneracies in the {αs(mZ), Ω1} parameter space could be alleviated upon fitting these parameters to experimental data for the angularity distributions.

We propose a novel strategy for the perturbative resummation of transverse momentum-dependent (TMD) observables, using the qT spectra of gauge bosons (γ∗, Higgs) in pp collisions in the regime of low (but perturbative) transverse momentum qT as a specific example. First we introduce a scheme to choose the factorization scale for virtuality in momentum space instead of in impact parameter space, allowing us to avoid integrating over (or cutting off) a Landau pole in the inverse Fourier transform of the latter to the former. The factorization scale for rapidity is still chosen as a function of impact parameter b, but in such a way designed to obtain a Gaussian form (in ln b) for the exponentiated rapidity evolution kernel, guaranteeing convergence of the b integral. We then apply this scheme to obtain the qT spectra for Drell-Yan and Higgs production at NNLL accuracy. In addition, using this scheme we are able to obtain a fast semi-analytic formula for the perturbative resummed cross sections in momentum space: analytic in its dependence on all physical variables at each order of logarithmic accuracy, up to a numerical expansion for the pure mathematical Bessel function in the inverse Fourier transform that needs to be performed just once for all observables and kinematics, to any desired accuracy.