Pub Date : 2023-09-20DOI: 10.5506/aphyspolbsupp.16.7-a19
A. Czarnecki, Y. Liu, S.N. Reza
We clarify two issues related to the so-called $D$-term in matrix elements of the energy-momentum tensor. First, we show that in a stable system, the $D$-term can have either sign, contrary to claims that it must be negative. Second, we demonstrate a logarithmic enhancement of the $mathcal{alpha}$ correction to the $D$-term in any state of the hydrogen atom. We contrast this enhancement with the Lamb shift where it is present only in S-states.
{"title":"Energy-momentum Tensor of a Hydrogen Atom: Stability, (D)-term, and the Lamb Shift","authors":"A. Czarnecki, Y. Liu, S.N. Reza","doi":"10.5506/aphyspolbsupp.16.7-a19","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.7-a19","url":null,"abstract":"We clarify two issues related to the so-called $D$-term in matrix elements of the energy-momentum tensor. First, we show that in a stable system, the $D$-term can have either sign, contrary to claims that it must be negative. Second, we demonstrate a logarithmic enhancement of the $mathcal{alpha}$ correction to the $D$-term in any state of the hydrogen atom. We contrast this enhancement with the Lamb shift where it is present only in S-states.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"82 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73650686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-18DOI: 10.5506/aphyspolbsupp.16.7-a5
K. Passek-K
Both deeply-virtual and photoproduction of mesons offer promising access to generalized parton distributions and complementary description of different kinematical regions. The higher-order contributions offer stabilizing effect with respect to the dependence on renormalization scales, while higher-twist effects have been identified as especially important in the case of the production of pseudo-scalar mesons. This was confirmed by recent evaluation of the complete twist-3 contribution to $pi$ and $eta$/$eta'$ photoproduction and its confrontation with experimental data.
{"title":"Deeply-virtual and Photoproduction of Mesons at Higher-order and Higher-twist","authors":"K. Passek-K","doi":"10.5506/aphyspolbsupp.16.7-a5","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.7-a5","url":null,"abstract":"Both deeply-virtual and photoproduction of mesons offer promising access to generalized parton distributions and complementary description of different kinematical regions. The higher-order contributions offer stabilizing effect with respect to the dependence on renormalization scales, while higher-twist effects have been identified as especially important in the case of the production of pseudo-scalar mesons. This was confirmed by recent evaluation of the complete twist-3 contribution to $pi$ and $eta$/$eta'$ photoproduction and its confrontation with experimental data.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73382065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-04DOI: 10.5506/aphyspolbsupp.16.6-a13
P. Mach, Andrzej Odrzywołek
We investigate stationary accretion of the collisionless Vlasov gas onto the Kerr black hole, occurring in the equatorial plane. At infinity the gas obeys the Maxwell-J"{u}ttner distribution, restricted to the equatorial plane. In the vicinity of the black hole, the motion of the gas is governed by the spacetime geometry. We compute accretion rates of the rest-mass, the energy, and the angular momentum, as well as the particle number surface density, focusing on the dependence of these quantities on the asymptotic temperature of the gas and the black hole spin. The accretion slows down the rotation of the black hole. We present preliminary results for a Vlasov gas accretion onto a Kerr black hole moving with a velocity parallel to the equatorial plane.
{"title":"Equatorial Accretion on the Kerr Black Hole","authors":"P. Mach, Andrzej Odrzywołek","doi":"10.5506/aphyspolbsupp.16.6-a13","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.6-a13","url":null,"abstract":"We investigate stationary accretion of the collisionless Vlasov gas onto the Kerr black hole, occurring in the equatorial plane. At infinity the gas obeys the Maxwell-J\"{u}ttner distribution, restricted to the equatorial plane. In the vicinity of the black hole, the motion of the gas is governed by the spacetime geometry. We compute accretion rates of the rest-mass, the energy, and the angular momentum, as well as the particle number surface density, focusing on the dependence of these quantities on the asymptotic temperature of the gas and the black hole spin. The accretion slows down the rotation of the black hole. We present preliminary results for a Vlasov gas accretion onto a Kerr black hole moving with a velocity parallel to the equatorial plane.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89302278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-08DOI: 10.5506/aphyspolbsupp.16.7-a17
S. Trojanowski
A new physics program has been initiated as part of the ongoing LHC physics run in the far-forward region, where dedicated FASER and SND@LHC experiments are currently taking data. We discuss the possible discovery prospects of this program in the search for signatures of beyond the Standard Model physics. We focus on both the present period and the proposed future Forward Physics Facility (FPF) that will operate in the high luminosity LHC era.
{"title":"Beyond the Standard Model Physics in the Far-forward Region of the Large Hadron Collider","authors":"S. Trojanowski","doi":"10.5506/aphyspolbsupp.16.7-a17","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.7-a17","url":null,"abstract":"A new physics program has been initiated as part of the ongoing LHC physics run in the far-forward region, where dedicated FASER and SND@LHC experiments are currently taking data. We discuss the possible discovery prospects of this program in the search for signatures of beyond the Standard Model physics. We focus on both the present period and the proposed future Forward Physics Facility (FPF) that will operate in the high luminosity LHC era.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"344 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77150200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-04DOI: 10.5506/aphyspolbsupp.16.5-a27
L. Alcerro
Recent results on inclusive jet production and production of a W boson in association with a charm quark by the CMS Collaboration are presented in this proceeding. The impact of these measurements on proton PDFs are also discussed.
{"title":"New Constraints on PDFs with CMS Data","authors":"L. Alcerro","doi":"10.5506/aphyspolbsupp.16.5-a27","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.5-a27","url":null,"abstract":"Recent results on inclusive jet production and production of a W boson in association with a charm quark by the CMS Collaboration are presented in this proceeding. The impact of these measurements on proton PDFs are also discussed.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"277 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75507611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-28DOI: 10.5506/aphyspolbsupp.16.7-a6
K. Cichy, S. Bhattacharya, M. Constantinou, J. Dodson, Xiang Gao, A. Metz, Joshua A. Miller, S. Mukherjee, Aurora Scapellato, F. Steffens, Yong Zhao
In recent years, there has been a breakthrough in lattice calculations of $x$-dependent partonic distributions. This encompasses also distributions describing the 3D structure of the nucleon, such as generalized parton distributions (GPDs). We report a new method of accessing GPDs in asymmetric frames of reference, relying on a novel Lorentz-covariant parametrization of the accessed off-forward matrix elements in boosted nucleon states. The approach offers the possibility of computationally more efficient determination of the full parameter dependence of GPDs and as such, it can contribute to better understanding of nucleon's structure.
{"title":"Generalized Parton Distributions from Lattice QCD","authors":"K. Cichy, S. Bhattacharya, M. Constantinou, J. Dodson, Xiang Gao, A. Metz, Joshua A. Miller, S. Mukherjee, Aurora Scapellato, F. Steffens, Yong Zhao","doi":"10.5506/aphyspolbsupp.16.7-a6","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.7-a6","url":null,"abstract":"In recent years, there has been a breakthrough in lattice calculations of $x$-dependent partonic distributions. This encompasses also distributions describing the 3D structure of the nucleon, such as generalized parton distributions (GPDs). We report a new method of accessing GPDs in asymmetric frames of reference, relying on a novel Lorentz-covariant parametrization of the accessed off-forward matrix elements in boosted nucleon states. The approach offers the possibility of computationally more efficient determination of the full parameter dependence of GPDs and as such, it can contribute to better understanding of nucleon's structure.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75946994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-25DOI: 10.5506/APhysPolBSupp.16.6-A10
Adam Cie'slik, P. Mach
The theory of Schwarzschild geodesics is revisited. Using a theorem due to Weierstrass and Biermann, we derive concise formulas describing all timelike and null trajectories in terms of Weierstrass elliptic functions. The formulation given in this note uses an analogue of the so-called Mino time.
{"title":"Timelike and Null Geodesics in the Schwarzschild Space-time: Analytical Solutions","authors":"Adam Cie'slik, P. Mach","doi":"10.5506/APhysPolBSupp.16.6-A10","DOIUrl":"https://doi.org/10.5506/APhysPolBSupp.16.6-A10","url":null,"abstract":"The theory of Schwarzschild geodesics is revisited. Using a theorem due to Weierstrass and Biermann, we derive concise formulas describing all timelike and null trajectories in terms of Weierstrass elliptic functions. The formulation given in this note uses an analogue of the so-called Mino time.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78725781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-12DOI: 10.5506/aphyspolbsupp.16.5-a6
Mikael Mieskolainen
We introduce GRANIITTI, a new Monte Carlo event generator designed especially to solve the enigma of glueballs at the LHC. We discuss the available physics processes, compare the simulations against STAR data from RHIC and span ambitious future directions towards the first diffractive event generator with a deep learning-enhanced computational engine.
{"title":"Graniitti: Towards a Deep Learning-enhanced Monte Carlo Event Generator for High-energy Diffraction","authors":"Mikael Mieskolainen","doi":"10.5506/aphyspolbsupp.16.5-a6","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.5-a6","url":null,"abstract":"We introduce GRANIITTI, a new Monte Carlo event generator designed especially to solve the enigma of glueballs at the LHC. We discuss the available physics processes, compare the simulations against STAR data from RHIC and span ambitious future directions towards the first diffractive event generator with a deep learning-enhanced computational engine.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88499714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-07DOI: 10.5506/aphyspolbsupp.16.7-a24
K. Deja, V. Martínez-Fernández, B. Pire, P. Sznajder, J. Wagner
Double deeply virtual Compton scattering (DDVCS) is the process where an electron scatters off a nucleon and produces a lepton pair. The main advantage of this process in contrast with deeply virtual and timelike Compton scatterings (DVCS and TCS) is the possibility of directly measuring GPDs for $xneqpmxi$ at leading order in $alpha_s$ (LO). We present a new calculation of the DDVCS amplitude based on the methods developed by R. Kleiss and W. J. Stirling in the 1980s. These techniques produce expressions for amplitudes that are perfectly suited for implementation in numerical simulations. Via the PARTONS software, the correctness of this new formulation has been tested by comparing the DVCS and TCS limits of DDVCS with independent calculations of DVCS and TCS.
双重深虚康普顿散射(DDVCS)是电子从核子散射并产生轻子对的过程。与深度虚拟和时间类康普顿散射(DVCS和TCS)相比，该方法的主要优点是可以直接测量$alpha_s$ (LO)中$xneqpmxi$领先阶的GPDs。本文根据R. Kleiss和W. J. Stirling在20世纪80年代提出的方法，提出了一种新的DDVCS振幅计算方法。这些技术产生的振幅表达式非常适合在数值模拟中实现。通过PARTONS软件，通过比较DDVCS的DVCS和TCS极限，并独立计算DVCS和TCS，验证了新公式的正确性。
{"title":"Prospects for GPDs Extraction with Double DVCS","authors":"K. Deja, V. Martínez-Fernández, B. Pire, P. Sznajder, J. Wagner","doi":"10.5506/aphyspolbsupp.16.7-a24","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.7-a24","url":null,"abstract":"Double deeply virtual Compton scattering (DDVCS) is the process where an electron scatters off a nucleon and produces a lepton pair. The main advantage of this process in contrast with deeply virtual and timelike Compton scatterings (DVCS and TCS) is the possibility of directly measuring GPDs for $xneqpmxi$ at leading order in $alpha_s$ (LO). We present a new calculation of the DDVCS amplitude based on the methods developed by R. Kleiss and W. J. Stirling in the 1980s. These techniques produce expressions for amplitudes that are perfectly suited for implementation in numerical simulations. Via the PARTONS software, the correctness of this new formulation has been tested by comparing the DVCS and TCS limits of DDVCS with independent calculations of DVCS and TCS.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80892708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-04DOI: 10.5506/aphyspolbsupp.16.7-a7
W. Broniowski, V. Shastry, E. Arriola
We analyze off-shell effects in the generalized parton distributions (GPDs) of the pion in the context of the Sullivan electroproduction process, as well as the corresponding half-off-shell electromagnetic and gravitational form factors. We illustrate our general results within a chiral quark model, where the off-shell effects show up at a significant level, indicating their contribution to uncertainties in the extraction of the GPDs from the future experimental data.
{"title":"Off-shell Generalized Parton Distributions of the Pion","authors":"W. Broniowski, V. Shastry, E. Arriola","doi":"10.5506/aphyspolbsupp.16.7-a7","DOIUrl":"https://doi.org/10.5506/aphyspolbsupp.16.7-a7","url":null,"abstract":"We analyze off-shell effects in the generalized parton distributions (GPDs) of the pion in the context of the Sullivan electroproduction process, as well as the corresponding half-off-shell electromagnetic and gravitational form factors. We illustrate our general results within a chiral quark model, where the off-shell effects show up at a significant level, indicating their contribution to uncertainties in the extraction of the GPDs from the future experimental data.","PeriodicalId":39158,"journal":{"name":"Acta Physica Polonica B, Proceedings Supplement","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78351260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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