[Theory-seminars] [theory-seminars] Jobs interviews. Wednesday and Friday 10am, Room F224

[Alessandro Pilloni]

CEBAF Center, Room F224
Wednesday, January 6th

10.00am - Daniele Paolo Anderle (Tubingen U.)
Higher order effects in lepton-hadron production processes
Abstract: With the ever increasing amount of precise data available for 
lepton-hadron processes, the perturbative QCD framework can be extended 
to explore effects and corrections that go beyond the next-to-leading 
order (NLO) accuracy. We have investigated some of those corrections 
such as threshold resumption of soft gluon emission for hadron 
multiplicities and spin asymmetries, Hadron Mass Corrections (HMC) and 
their interplay for Deep-Inelastic Scattering (DIS) and Semi-Inclusive 
e+ e- Annihilation, and next-to-next-to leading order (NNLO) corrections 
to the longitudinal structure function for Semi-Inclusive DIS (SIDIS). 
We also present our study towards a global NNLO fit of Fragmentation 
Functions together with the extension to the small x-region which we are 
currently working on.

10.45am - Andrea Signori (Vrije U.)
A path into TMD phenomenology
Abstract: I will review some aspects of phenomenology of 
Transverse-Momentum-Dependent distributions (TMDs) that I have been 
investigating during my PhD and which are potentially interesting for 
the 12 GeV physics program at Jefferson Lab. In particular, I will 
address the flavor dependence of intrinsic transverse momentum in 
unpolarized TMDs, focusing on its extraction from Semi-Inclusive 
Deep-Inelastic Scattering (SIDIS) data and its impact on 
electron-positron annihilation and proton-proton collisions. Moreover, I 
will describe the TMD factorization theorem for the qT-spectrum of 
quarkonium produced in proton-proton collisions and the possibility to 
extract from it precise information on (un)polarized gluon TMD PDFs. 
Finally, I will present some new TMD structures and discuss their link 
to small-x physics.

11.30am - Xiaonu Xiong (INFN Pavia)
Hadron Structure: A Large Momentum Effective field Theory Approach
Abstract: The light-cone parton distributions can be accessed by a large 
momentum limit (Large Momentum Effective field Theory, LaMET) of 
space-like correlation functions (quasi distribution) which can be 
directly simulated on lattice. The perturbative matching conditions 
between light-cone and quasi PDF and GPD are discussed. We present a 
test of LaMET performed with heavy meson distribution amplitudes which 
are perturbatively calculable through NRQCD refactorization. Recently, A 
non-perturbative test using 2-D large Nc QCD is performing. I will also 
discuss the parton orbital angular momentum and twist-3 GPD measurement 
through hard exclusive processes which can potentially performed on JLab 
and future EIC .

12.15pm - Federico Alberto Ceccopieri (Liege U.)
Particle production in the DIS target fragmentation region
Abstract: After a brief overview of my personal background and recent 
research activities, I will discuss particle production in the target 
fragmentation region of Semi-Inclusive Deep Inelastic Scattering (SIDIS) 
within the framework of fracture functions. Such distributions 
simultaneously encode information both on the parton partecipating the 
hard scattering and on the fragmentation of the spectator system into 
the observed hadron. Their scale dependence is calculable within 
perturbative QCD an a dedicated factorisation theorem guarantees that 
they are universal distributions, at least in the context of SIDIS. 
Focusing on Lambda hyperons, which are predominantly produced in the 
SIDIS target fragmentation region, I present a recently obtained set of 
Lambda fracture functions obtained by performing a QCD fit to a variety 
of Semi-Inclusive Lambda production data collected in lepton-nucleon 
scattering. By using this set, we present predictions for Lambda 
observables in the target fragmentation region of neutral current DIS in 
CLAS at 12 GeV kinematics and discuss the physics potential of such 
measurements at this facility.

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CEBAF Center, Room F224
Friday, January 8th

10:00am - Jeremy Green (Mainz U.)
Nucleon strange electromagnetic form factors from lattice QCD
Abstract: We report a direct lattice QCD calculation of the strange 
nucleon electric and magnetic form factors. By using high statistics and 
a variance reduction technique called hierarchical probing, we obtain a 
clear nonzero signal for both form factors for the first time. We fit 
the Q^2-dependence and determine the strange magnetic moment as well as 
the strange electric and magnetic radii. We compare our results to data 
from parity-violating electron-proton scattering and to other 
theoretical studies.

10:45am - Padmanath Madanagopalan (Graz U.)
Excited heavy hadrons from lattice QCD
Abstract: As per the invitation I got, for the first five minutes I will 
discuss my biography, preferably focussing details beyond what is 
discussed in my CV. During the remaining 20 minutes I will discuss: my 
research experience and achievements, emphasizing heavy hadron (mesons, 
baryons and tetra-quarks) spectroscopy from lattice QCD, till now and 
the current calculations that I am involved in. Emphasis will be given 
on calculations involving the usage of state-of-the-art lattice 
technologies like derivative-based operator construction, distillation 
and variational method.

11:30am - Bipasha Chakraborty (Glasgow U.)
High precision tests of the Standard Model using lattice QCD
Abstract: In this talk, I will briefly discuss my research to test the 
Standard Model (SM) of particle physics with high precision and look for 
signs of new physics using first principle lattice QCD calculations, 
particularly, in the low energy (~ 1 GeV) regime of QCD, the SU(3) 
component of the SM. The anomalous magnetic moment of the muon (a_μ), 
measured with an impressive accuracy of 0.54 parts per million in 
experiment, provides one of the most stringent tests of the SM. 
Intriguingly, the experimentally measured anomaly disagrees by around 3 
standard deviations with the calculated value from the SM. The current 
theoretical uncertainty is dominated by that from the calculation of the 
lowest order "hadronic vacuum polarisation (HVP)". Improvements in the 
experimental uncertainty by a factor of 4 in the upcoming experiments at 
Fermilab and J-PARC are expected and improvements in the theoretical 
determination would make the discrepancy (if it remains) really 
compelling. I will present my results for improving the theoretical 
calculation of the HVP contribution to the anomaly using our (HPQCD) new 
lattice QCD method (Phys.Rev. D89 (2014) 11, 114501; arXiv:1511.05870; 
arXiv:1512.03270).
The quark flavour sector of the SM is also known to be potentially very 
sensitive to new physics effects. Studying different flavour-changing 
processes like leptonic and semi-leptonic decays of mesons and 
over-constraining the elements of the Cabibbo-Kobayashi-Maskawa (CKM) 
unitary matrix may lead to an internal inconsistency signalling beyond 
Standard Model (BSM) physics. In the second part of this talk I will 
focus on the progress of my calculation of V_cs, the central CKM matrix 
element, by comparing the lattice QCD results for the scalar and vector 
form factors associated with D → Klν semi-leptonic decay and the 
experimental decay rate.

12:15pm - Ben Hoerz (Trinity College)
TBA

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