[Hadstruct] [EXTERNAL] Re: Proposed abstracts for Lattice 2021

Thu Apr 29 12:33:04 EDT 2021

Hi All,

I'll add one more in this list of abstracts. Should I be unable to present
during the meeting, I will arrange with Christos on how to best present our
findings.
As for co-authors, I have: Christos, Kostas, Anatoly, David, Eloy and
Savvas.

Title:
Towards High-Precision Parton Distributions via Distillation

Abstract:
The pseudo-distribution formalism is one such methodology capable of
illuminating the collinear structure of hadrons from matrix elements of
suitably constructed space-like operators calculated using lattice QCD.
Leveraging the distillation spatial smearing program, we extract the
unpolarized isovector valence and plus quark PDFs of the nucleon via a
direct 1-loop matching of the computed Ioffe-time pseudo-distribution and
PDF parameterizations. The tempering of excited-states and improved volume
sampling afforded by distillation lead to high quality Ioffe-time
pseudo-distributions and their $\overline{\text{MS}}$ light-cone
counterparts. This bolsters confidence in the extracted PDFs, and allows
for a rigorous quantitative accounting of lattice systematics. The PDFs we
determine are compared with contemporary results from the lattice community
and an array of phenomenological determinations.

Thanks,
Colin

On Thu, Apr 29, 2021 at 12:25 PM Raza Sufian <sufian at jlab.org> wrote:

> Dear All,
>
> Below please find my abstract. Since I do not know yet whether matrix
> elements of pseudo-PDF or LCS or both can have signal, I do not mention any
> formalism and just say Ioffe-time distribution.
>
> *Title: Towards determining polarized gluon distribution from lattice QCD*
>
> *Abstract: We present a calculation of lattice QCD non-local matrix
> elements that can be used to determine polarized gluon Ioffe-time
> distribution and the corresponding parton distribution function using QCD
> short distance factorization. We construct the nucleon interpolation fields
> using the distillation technique and flow the gauge fields using the
> gradient flow technique. Our calculation is performed on a $32^3 \times
> 64$ **isotropic lattice with a pion mass of 358 MeV.*
>
> Thank you.
> -Raza
>
> On Apr 29, 2021, at 11:27 AM, Wayne Morris <wmorr001 at odu.edu> wrote:
>
> *Unpolarized and polarized gluon pseudo-distributions at short distances:
> Forward case*
>
> We present the results that are necessary in the ongoing lattice
> calculations of the unpolarized and polarized gluon parton distribution
> functions (PDFs) within the pseudo-PDF approach. We give a classification
> of possible two-gluon correlator functions and identify those that contain
> the invariant amplitude determining the gluon PDF in the light-cone $z^2\to
> 0$ limit. One-loop calculations have been performed in the coordinate
> representation and in an explicitly gauge-invariant form. We made an effort
> to separate ultraviolet (UV) and infrared (IR) sources of the $\ln
> \left(-z^2\right) $-dependence at short distances $z^2$. The UV terms
> cancel in the reduced Ioffe-time distribution (ITD), and we obtain the
> matching relation between the reduced ITD and the light-cone ITD. Using a
> kernel form, we get a direct connection between lattice data for the
> reduced ITD and the normalized gluon PDF.
>
> On Thu, Apr 29, 2021 at 11:09 AM Md Tanjib Atique Khan <
> mkhan01 at email.wm.edu> wrote:
>
>> Dear all,
>>
>> Here is my abstract for Lattice21.
>>
>> Title: Calculation of the Gluon PDF using Pseudo-PDF technique
>>
>> Abstract:
>>
>> We present our calculation of the unpolarized gluon parton distribution function (PDF) in the nucleon using Pseudo-PDF technique on a $32^3 \times 64$
>> isotropic lattice with a pion mass of 358 MeV. The nucleon interpolating fields are constructed using the distillation method while the sGEVP method is
>> used to calculate the gluonic matrix elements. We implement the gradient-flow technique to compute the flowed matrix elements and using the double ratio,
>> calculate the flowed reduced Ioffe-time distribution (rITD). We extrapolate the results to the flow-time independent rITD and calculate the light-cone ITD
>> in $\overline{MS}$ scheme, at the small z-separation limit, using NLO matching formula. Finally, the gluon PDF is calculated from the light-cone ITD by
>> applying appropriate kernel form.
>>
>> Thanks,
>>
>> Tanjib
>>
>>
>> On Wed, Apr 28, 2021 at 5:55 PM Savvas Zafeiropoulos <savvaslz at gmail.com>
>> wrote:
>>
>>> Dear All,
>>>
>>> here is my abstract and title for lattice 2021
>>>
>>> *Progress on the extraction of parton distributions from Ioffe time
>>> distributions*
>>>
>>> The light-cone definition of Parton Distribution Functions (PDFs) does
>>> not allow for a direct ab initio determination employing methods of Lattice
>>> QCD simulations that naturally take place in Euclidean spacetime. In this
>>> presentation we focus on pseudo-PDFs where the starting point is the equal
>>> time hadronic matrix element with the quark and anti-quark fields separated
>>> by a finite distance. We focus on Ioffe-time distributions, which are
>>> functions of the Ioffe-time ν, and can be understood as the Fourier
>>> transforms of parton distribution functions with respect to the momentum
>>> fraction variable x. We present lattice results for the case of the nucleon
>>> addressing the physical point and continuum extrapolations. We also
>>> incorporate our lattice data in the NNPDF framework treating them on the
>>> same footing as experimental data and discuss in detail the different
>>> sources of systematics in the determination of the non-singlet PDFs.
>>>
>>> Since I am going to present results from three published papers all the
>>> authors of those papers will be contributors for my talk in the indico
>>> website.
>>> If anyone has a suggestion/correction etc please let me know!
>>>
>>> Best,
>>> Savvas
>>>
>>> On Wed, Apr 28, 2021 at 3:55 PM Raza Sufian <sufian at jlab.org> wrote:
>>>
>>>> Dear All,
>>>>
>>>> Below please find the proposed abstracts for the Lattice 2021
>>>> conference. The deadline for abstract submission is on Friday, April 30.
>>>> Please try to circulate your abstracts sometime tomorrow for comments.
>>>> Please let us know if I forgot to list any other proposed abstract.
>>>>
>>>> CK: Nucleon valence distribution using distillation
>>>>
>>>> SZ: Nucleon valence distribution (continuum limit, physical point
>>>> extrapolation + NNPDF analysis)
>>>>
>>>> TK: Unpolarized gluon distribution
>>>>
>>>> JK: RBC/UKQCD
>>>>
>>>> NK: Transversity
>>>>
>>>> RSS: Polarized gluon distribution
>>>>
>>>> WM: Perturbative matching for …
>>>>
>>>>
>>>> *TBD:*
>>>>
>>>> Patrick Barry
>>>>
>>>> CE
>>>>
>>>> Thank you.
>>>> -Raza
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