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Matthew Lim (Universita' di Milano-Bicocca)19/04/2022, 13:00
The N-jettiness is a useful resolution variable to distinguish between events with a different number of jets in the final state. It has been successfully employed in slicing calculations for colour singlet processes at NNLO and its resummation forms the basis for the GENEVA approach to matching NNLO calculations to parton showers. I will discuss the extension of the zero-jettiness resummation...
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Yibei Li19/04/2022, 13:30
Track functions describe the collective effect of the fragmentation of quarks and gluons into charged hadrons, making them a key ingredient for jet substructure measurements at hadron colliders, where track-based measurements offer superior angular resolution. Measurements of higher-point correlations of energy flow necessitate a characterization of fluctuations in the hadronization process,...
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Basem El-Menoufi19/04/2022, 14:00
Higher-order splitting kernels comprise an essential ingredient for enhancing the logarithmic accuracy of parton showers. Beyond NLL, collinear dynamics of quark and gluon splitting at NLO is encoded in the triple-collinear splitting functions. This talk provides latest insights into various ingredients that enter the construction of higher-order parton showers. First, I will show that...
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Arindam Bhattacharya19/04/2022, 14:30
Sudakov shoulders are large logarithms of event shape observables that occur in the interior of the allowed phase space, in contrast to Sudakov peaks which occur at the boundary of phase space. Starting from a factorization theorem in SCET, we present a resummation of the Sudakov shoulder occurring in heavy jet mass and thrust near the trijet configuration (corresponding to a value of...
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Samuel Clément Favrod19/04/2022, 15:00
In order to differentiate photons produced from different origins at hadrons collider, it is necessary to impose some isolation requirements. For cones with small radius $R$, photon isolation effect can be captured by a fragmentation function describing the fragmentation of a parton into a photon accompanied by soft radiation. We computed these fragmentation functions for fixed energy cone and...
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Pedro Cal19/04/2022, 16:00
Power counting is a systematic strategy for organizing collider observables and their associated theoretical calculations.In this paper, we use power counting to characterize a class of jet substructure observables called energy flow polynomials (EFPs).
EFPs provide an overcomplete linear basis for infrared-and-collinear safe jet observables, but it is known that in practice, a small subset...
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Dr Bianka Meçaj (Yale University)19/04/2022, 16:30
Many searches for New Physics and precision measurements in QCD involve the study of jet substructure for final state hadrons. While traditionally the state of the art for studying jets at particle colliders have been event shape observables, recently it has been better understood that measuring correlation functions of energy flow operators inside a jet is in fact a very powerful tool for...
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Dr Aditya Pathak (University of Manchester)19/04/2022, 17:00
One of the most important goals of the precision collider physics program is to push beyond the sub-percent accuracy of the current top quark mass measurement. This involves looking for observables that are both sensitive to the top mass and can be brought under theoretical control. Satisfying both these criterion at the LHC is a challenging task due to contributions from soft physics and the...
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Kyle Lee19/04/2022, 17:30
Reframing jet substructures in terms of multipoint correlation functions of energy flow light-ray operators offers new means to study the dynamics of QCD jets, providing many interesting phenomenological applications (including QCD fragmentation, track functions, precision measurements, and more) and allowing applications of theoretical developments in the study of conformal field...
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Matthias Neubert20/04/2022, 09:00
Jet cross sections at high-energy colliders exhibit intricate patterns of logarithmically enhanced higher-order corrections. In particular, so-called nonglobal logarithms emerge from soft radiation emitted off energetic partons inside jets. While this is a single-logarithmic effect at lepton colliders, at hadron colliders phase factors in the amplitudes lead to double-logarithmic corrections...
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Michel Stillger (JGU Mainz)20/04/2022, 09:30
The higher-order behavior of logarithmically enhanced contributions in non-global observables is very intricate, in particular as double-logarithmic corrections may arise first at very high orders in perturbation theory. Recently, the resummation of these super-leading logarithms (SLLs) to all orders for generic $2\rightarrow l$ scattering processes at hardron colliders has been achieved [1]....
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Xu Xiaofeng20/04/2022, 10:00
The soft radiation emitted in jet cross sections can resolve the directions and colors of individual hard partons, leading to a complicated pattern of logarithmically enhanced terms in the perturbative series. Starting from a factorization theorem and solving the renormalization group equations for its ingredients, these large logarithms can be resummed. We extract the two-loop anomalous...
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Pier Francesco Monni (CERN)20/04/2022, 11:00
We present a formalism for the resummation of non-global QCD observables beyond leading logarithmic accuracy. We discuss the derivation of a set of integro-differential equations that governs the dynamics of soft radiation in the planar limit, using which we perform a calculation of the out-of-jet transverse energy distributions at lepton colliders. We finally comment on the solution of the...
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Sanjay Raman20/04/2022, 11:30
The exchange of Glauber particles in SCET can be used to study QCD scattering amplitudes in the Regge limit. At NNLL level, the RGE for Regge 2-to-2 scattering amplitudes are not currently known. In this talk, I will use the tools of SCET to study the RGE structure of the three-loop Glauber exchange amplitude, which specifies these terms. SCET consistency relations between the soft and...
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Varun Vaidya20/04/2022, 12:00
I will talk about an EFT formulation for understanding the physics of saturation in Deep Inelastic scattering using the Glauber EFT for forward scattering. I ll show how to derive a factorization formula that manifestly decouples the physics of the probe, the Quark-antiQuark Dipole, from the universal physics of the medium, namely a hadron or a large nucleus, by treating the probe as an Open...
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Stella Schindler20/04/2022, 14:00
SCET enables the factorization of cross-sections into perturbative and non-perturbative components. The resulting non-perturbative functions are typically modeled with essentially no direct input from lattice QCD calculations. The fact that their dynamics are dominated by the lightcone typically renders them inaccessible to direct lattice QCD calculations due to a sign problem, a speculated...
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Justin Lieffers20/04/2022, 14:30
Factorization of Semi-Inclusive Deep Inelastic Scattering (SIDIS) has been derived in multiple ways using the methods of perturbative QCD, and more recently soft collinear effective theory (SCET). In this work, we carry out precision phenomenology for Jefferson Lab experiments and possible experiments at the electron-ion collider. We work to next-to-leading order in matching, and...
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Ignazio Scimemi20/04/2022, 15:00
The understanding of cross sections differential in transverse momenta are known to be factorizable with TMD in the low energy spectrum. In order achieve a complete description it is necessary to explore the power expansion that allows this factorization beyond the leading order. We have have recently considered a systematic method to perform the power expansion and the complete basis of...
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Alexey Vladimirov20/04/2022, 15:30
The TMD factorization at the next-to-leading power has an involved structure of singularities. I discuss the definition and properties of transverse momentum dependent (TMD) distributions of the twist-three including evolution, symmetry relations, parametrization, interpretation, and singularities. I demonstrate that the physical TMD distributions (those express cross-sections) require an...
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Anjie Gao20/04/2022, 16:30
TMD distributions depending on the azimuthal angle provide a non-trivial example of observables that start at O(lambda) in the power expansion. They also have a long history, for example in 1978 Cahn showed that quark transverse momentum gives rise to an azimuthal cos(phi) asymmetry of the outgoing hadrons in semi-inclusive DIS (SIDIS). Such subleading distributions also are an interesting...
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Simone Rodini (University of Regensburg)20/04/2022, 17:00
The theory and phenomenology of transverse-momentum dependent parton distributions (TMDs) have seen increasing activity in the past years. Factorization theorems for both leading-power (LP) and next-to-leading power (NLP) scenario has been discussed in the context of experimental processes such as Drell-Yan (DY) or SIDIS.
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However, experimental determination of all TMD distributions is an... -
Max Jaarsma (Universiteit van Amsterdam)20/04/2022, 17:30
In a factorization approach to double parton scattering, the initial state is described by double parton distributions (DPDs). These functions are currently poorly constrained by experiment, but provide a view on interesting correlations between partons in the hadron. We show that DPDs can be calculated from first principles using lattice QCD via the quasi-PDF approach, opening up a new way to...
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Johannes Michel (MIT CTP)21/04/2022, 09:00
We present state-of-the-art SCETlib predictions for the $W$ and $Z/\gamma^*$ transverse-momentum ($q_T$) distributions at the LHC at complete three-loop order in resummed perturbation theory (N$^3$LL$'$) and matched to available fixed order. We pay particular attention to the estimation of theory uncertainties via profile scale variations in such a way that perturbative uncertainties due to...
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Tongzhi Yang21/04/2022, 09:30
The CERN Large Hadron Collider is a precision machine to test the Standard Model and demands equally precise theoretical predictions. State-of-the-art theory calculations at next-to-next-to-next-to-leading order (N3LO) in perturbative QCD are only available for a limited set of processes and observables. We compute for the first time the differential di-lepton rapidity distribution for the...
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Yair Mulian21/04/2022, 10:00
We describe the perturbative calculation of the transverse parton distribution functions in the quark-quark channel up to next-to-next-to-leading order, based on the technique of light-cone perturbation theory. The computation consists of separate computation of Feynman diagrams, demonstrating the cancellation of both UV and IR light-cone divergences. The result serves as a check for a...
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Julian Strohm21/04/2022, 11:00
The off-diagonal partonic channels do not contribute at leading power in hard scattering but appear first at next-to-leading power (NLP). In contrast to the diagonal channels, leading logarithms are already non-trivial and resummation requires new, refined methods. Techniques developed at leading power cannot be readily utilized since endpoint divergences spoil NLP factorization. In four...
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Yao Ji21/04/2022, 11:30
In this talk, I will present our calculation of kinematic power corrections $t/Q^2$ and $m^2/Q^2$ to the amplitude of deeply-virtual Compton scattering to the twist-six accuracy.
Phenomenologically, this result reduces an important source of uncertainties in the QCD predictions for intermediate momentum transfers $Q^2 \sim 1-10 ~{\rm GeV}^2$, which are accessible in the existing and planned...
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Xing Wang21/04/2022, 12:00
Based on our previous series of work, we present the full resummation at RG-improved leading order for $h\rightarrow\gamma\gamma$ decay amplitudes induced by light quarks. We analytically show that endpoint divergences cancel in the plus-type subtraction scheme after scale evolution and use a slicing method to do the numerical evaluation. We find logarithms beyond NLL are significant.
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Samuel Abreu (CERN)21/04/2022, 14:00
We present the calculation of the two-loop soft and beam functions for the transverse-momentum distribution of the leading jet produced in association with any colour-singlet system (e.g. a Higgs or a Z boson). This constitutes a central ingredient for the resummation of the above distribution as well as the jet-vetoed cross section at the next-to-next-to-next-to-leading logarithmic order.
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Marcel Wald (University of Siegen)21/04/2022, 14:30
We present a novel formalism to calculate beam and jet functions automatically at next-to-next-to-leading order in perturbation theory. By employing suitable phase-space parameterisations in combination with sector-decomposition steps and selector functions, we managed to factorise all divergences in the phase-space integrations and we implemented our framework in the publicly available code...
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Jürg Andreas Haag21/04/2022, 15:00
We consider the class of inclusive hadron collider processes in which several energetic jets are produced, possibly accompanied by colourless particles (such as Higgs boson(s), vector boson(s) with their leptonic decays, and so forth).
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We propose a new variable that smoothly captures the
$N+1$ to $N$-jet transition. This variable, that we dub $k_T^{\rm ness}$, represents an effective... -
Dr Gherardo Vita (SLAC)21/04/2022, 15:30
In this talk I present upcoming results regarding resummation at 4 loops for differential distributions.
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Ian Balitsky21/04/2022, 16:30
The scale of a coupling constant for rapidity evolution of TMD operators in the Sudakov region is calculated using BLM procedure. The effective scale for a coupling constant
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is halfway in logarithmical scale between the transverse momentum and energy of TMD distribution. The resulting rapidity-only evolution equation is solved for quark and gluon TMDs. -
Giovanni Antonio Chirilli21/04/2022, 17:00
To calculate the PDFs from first principles in Lattice gauge theories it is convenient to consider the Ioffe-time distribution defined through gauge-invariant bi-local operators with spacelike separation. Lattice calculations provide values for a limited range of the distance separating the bi-local operators. In order to perform the Fourier transform and obtain the pseudo- and the quasi-PDFs,...
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Rafael F. del Castillo21/04/2022, 17:30
We discuss the measurement of gluon transverse momentum distribution (TMD) in dijet and heavy hadron pair (HHP) production in semi-inclusive deep inelastic scattering. The factorization of these processes in position space shows the appearance of a specific new soft factor matrix element on top of angular and complex valued anomalous dimensions. We show in detail how these features can be...
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Chris Hays (University of Oxford (GB))22/04/2022, 09:00
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Chen-Yu Wang (TTP, KIT)22/04/2022, 09:30
The advancement of computation techniques enables a number of N3LO calculations in perturbative QCD, which are crucial to reaching percent level accuracy in the LHC (and the upcoming HL-LHC) phenomenology. An important part of this effort involves properly extracting IR singularities at N3LO. The N-jettiness slicing scheme is one of the techniques to deal with this problem, but is only...
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Ivan Novikov (Deutsches Elektronen-Synchrotron (DE))22/04/2022, 10:00
SCET lies at the foundation of our understanding of inclusive B meson decays. It allows us to factorize the spectrum into hard, jet, and hadronic soft functions. The hadronic soft function can be further factorized into perturbative partonic soft function and nonperturbative shape function. The shape function is a necessary ingredient for extraction of $|V_{ub}|$ CKM matrix element from $B\to...
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Patrick Hager22/04/2022, 11:00
At first sight, perturbative gravity and gauge theory differ quite drastically at the Lagrangian level.
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Whereas the soft limits of both theories share many similarities, their respective collinear limits are distinct. Notably, unlike gauge theory, gravity does not feature any collinear divergences.
This motivates the construction of the soft-collinear effective theory for gravity in analogy... -
Oleksandr Tomalak22/04/2022, 11:30
SCET is an extremely powerful tool for the evaluation of radiative corrections in neutrino experiments. I am going to highlight two recent advances: 1. Charged-current quasielastic scattering is the signal process in modern neutrino oscillation experiments. Exploiting effective field theory, we factorize neutrino-nucleon cross sections into soft, collinear, and hard contributions. We evaluate...
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Marat Freytsis (Rutgers University)22/04/2022, 12:00
Quantum simulations of the full dynamics of a quantum field theory over a wide range of energies requires exceptionally large resources. Yet for many observables in particle physics, perturbative techniques are sufficient to accurately model all but a constrained range of energies within the validity of the theory. SCET naturally provides an efficient separation of dynamics well-described by...
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TBD
We'll try to schedule a talk on the new CDF W-mass measurement in this slot.
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Philipp Böer (JGU Mainz)
Exclusive non-leptonic $B$-meson decays provide a precision laboratory for tests of flavour-changing weak transitions. While the factorization of the decay amplitude is well understood in the heavy-quark limit since more than two decades, very little is known so far about power-corrections. One particular class of such suppressed effects are the so-called weak-annihilation topologies. With the...
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