341 results on '"Ebert, Markus"'
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2. Jettiness formulation of the MINNLO$_{\text{PS}}$ method
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Ebert, Markus, Rottoli, Luca, Wiesemann, Marius, Zanderighi, Giulia, and Zanoli, Silvia
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
We present a new formulation of the MINNLO method to match NNLO QCD calculations with parton showers by using jettiness as a resummation variable. The full derivation for colour-singlet processes is presented using $0$-jettiness starting from the NNLL$^\prime$ resummation formula. We show phenomenological results for Drell-Yan and Higgs-boson production at the LHC and compare our predictions to ATLAS and CMS data. Differences to the original MINNLO formulation using the transverse momentum of the colour singlet as resummation variable are discussed. We further present a comparison of MINNLO predictions with GENEVA. Finally, we extend the formulation of the MINNLO method to 1-jettiness which is applicable to processes with a colour singlet plus one jet in the final state., Comment: 51 pages, 8 figures
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- 2024
3. TMD Handbook
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Boussarie, Renaud, Burkardt, Matthias, Constantinou, Martha, Detmold, William, Ebert, Markus, Engelhardt, Michael, Fleming, Sean, Gamberg, Leonard, Ji, Xiangdong, Kang, Zhong-Bo, Lee, Christopher, Liu, Keh-Fei, Liuti, Simonetta, Mehen, Thomas, Metz, Andreas, Negele, John, Pitonyak, Daniel, Prokudin, Alexei, Qiu, Jian-Wei, Rajan, Abha, Schlegel, Marc, Shanahan, Phiala, Schweitzer, Peter, Stewart, Iain W., Tarasov, Andrey, Venugopalan, Raju, Vitev, Ivan, Yuan, Feng, and Zhao, Yong
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice ,Nuclear Theory - Abstract
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., Comment: 471 pages, many figures
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- 2023
4. Factorization connecting continuum and lattice TMDs
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Ebert, Markus A., Schindler, Stella T., Stewart, Iain W., and Zhao, Yong
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice ,Nuclear Theory - Abstract
Transverse-momentum-dependent parton distribution functions (TMDs) can be studied from first principles by a perturbative matching onto lattice-calculable quantities: so-called lattice TMDs, which are a class of equal-time correlators that includes quasi-TMDs and TMDs in the Lorentz-invariant approach. We introduce a general correlator that includes as special cases these two Lattice TMDs and continuum TMDs, like the Collins scheme. Then, to facilitate the derivation of a factorization relation between lattice and continuum TMDs, we construct a new scheme, the Large Rapidity (LR) scheme, intermediate between the Collins and quasi-TMDs. The LR and Collins schemes differ only by an order of limits, and can be matched onto one another by a multiplicative kernel. We show that this same matching also holds between quasi and Collins TMDs, which enables us to prove a factorization relation between these quantities to all orders in $\alpha_s$. Our results imply that there is no mixing between various quark flavors or gluons when matching Collins and quasi TMDs, making the lattice calculation of individual flavors and gluon TMDs easier than anticipated. We cross-check these results explicitly at one loop and discuss implications for other physical-to-lattice scheme factorizations., Comment: 33 pages + appendices, 6 figures
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- 2022
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5. Disentangling Long and Short Distances in Momentum-Space TMDs
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Ebert, Markus A., Michel, Johannes K. L., Stewart, Iain W., and Sun, Zhiquan
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High Energy Physics - Phenomenology - Abstract
The extraction of nonperturbative TMD physics is made challenging by prescriptions that shield the Landau pole, which entangle long- and short-distance contributions in momentum space. The use of different prescriptions then makes the comparison of fit results for underlying nonperturbative contributions not meaningful on their own. We propose a model-independent method to restrict momentum-space observables to the perturbative domain. This method is based on a set of integral functionals that act linearly on terms in the conventional position-space operator product expansion (OPE). Artifacts from the truncation of the integral can be systematically pushed to higher powers in $\Lambda_{\rm QCD}/k_T$. We demonstrate that this method can be used to compute the cumulative integral of TMD PDFs over $k_T \le k_T^\mathrm{cut}$ in terms of collinear PDFs, accounting for both radiative corrections and evolution effects. This yields a systematic way of correcting the naive picture where the TMD PDF integrates to a collinear PDF, and for unpolarized quark distributions we find that when renormalization scales are chosen near $k_T^\mathrm{cut}$, such corrections are a percent-level effect. We also show that, when supplemented with experimental data and improved perturbative inputs, our integral functionals will enable model-independent limits to be put on the nonperturbative OPE contributions to the Collins-Soper kernel and intrinsic TMD distributions., Comment: 39 pages + appendices and references, 15 figures; v2: journal version
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- 2022
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6. Factorization for Azimuthal Asymmetries in SIDIS at Next-to-Leading Power
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Ebert, Markus A., Gao, Anjie, and Stewart, Iain W.
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High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
Differential measurements of the semi-inclusive deep inelastic scattering (SIDIS) process with polarized beams provide important information on the three-dimensional structure of hadrons. Among the various observables are azimuthal asymmetries that start at subleading power, and which give access to novel transverse momentum dependent distributions (TMDs). Theoretical predictions for these distributions are currently based on the parton model rather than a rigorous factorization based analysis. Working under the assumption that leading power Glauber interactions do not spoil factorization at this order, we use the Soft Collinear Effective Theory to derive a complete factorization formula for power suppressed hard scattering effects in SIDIS. This yields generalized definitions of the TMDs that depend on two longitudinal momentum fractions (one of them only relevant beyond tree level), and a complete proof that only the same leading power soft function appears and can be absorbed into the TMD distributions at this order. We also show that perturbative corrections can be accounted for with only one new hard coefficient. Factorization formulae are given for all spin dependent structure functions which start at next-to-leading power. Prospects for improved subleading power predictions that include resummation are discussed., Comment: 118 pages, 1 figure; Update fixing typos and with complex C^(1) [JHEP erratum version]
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- 2021
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7. Analytic results for Sudakov form factors in QCD
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Ebert, Markus A.
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High Energy Physics - Phenomenology - Abstract
Sudakov form factors appear ubiquitously in factorized cross sections where they allow one to resum large logarithms to all orders in perturbation theory. Their exact evaluation requires numerical integrals over anomalous dimensions, which in practice can hamper efficiency. Alternatively, one can use approximate analytic solutions, which provide fast evaluation at the cost of numerical precision and loss of properties such as renormalization group invariance. We provide an exact analytic expression of the QCD Sudakov form factor which allows one to obtain fast and numerically exact results.
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- 2021
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8. Higgs $p_T$ Spectrum and Total Cross Section with Fiducial Cuts at Third Resummed and Fixed Order in QCD
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Billis, Georgios, Dehnadi, Bahman, Ebert, Markus A., Michel, Johannes K. L., and Tackmann, Frank J.
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
We present predictions for the gluon-fusion Higgs $p_T$ spectrum at third resummed and fixed order (N$^3$LL$'+$N$^3$LO) including fiducial cuts as required by experimental measurements at the Large Hadron Collider. Integrating the spectrum, we predict for the first time the total fiducial cross section to third order (N$^3$LO) and improved by resummation. The N$^3$LO correction is enhanced by cut-induced logarithmic effects and is not reproduced by the inclusive N$^3$LO correction times a lower-order acceptance. These are the highest-order predictions of their kind achieved so far at a hadron collider., Comment: 5 pages, 3 figures; v2: journal version (adjusted title, more details on nonsingular fit, note added)
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- 2021
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9. The Energy-Energy Correlation in the back-to-back limit at N$^3$LO and N$^3$LL$^\prime$
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Ebert, Markus A., Mistlberger, Bernhard, and Vita, Gherardo
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High Energy Physics - Phenomenology ,High Energy Physics - Theory ,Nuclear Theory - Abstract
We present the analytic formula for the Energy-Energy Correlation (EEC) in electron-positron annihilation computed in perturbative QCD to next-to-next-to-next-to-leading order (N$^3$LO) in the back-to-back limit. In particular, we consider the EEC arising from the annihilation of an electron-positron pair into a virtual photon as well as a Higgs boson and their subsequent inclusive decay into hadrons. Our computation is based on a factorization theorem of the EEC formulated within Soft-Collinear Effective Theory (SCET) for the back-to-back limit. We obtain the last missing ingredient for our computation - the jet function - from a recent calculation of the transverse-momentum dependent fragmentation function (TMDFF) at N$^3$LO. We combine the newly obtained N$^3$LO jet function with the well known hard and soft function to predict the EEC in the back-to-back limit. The leading transcendental contribution of our analytic formula agrees with previously obtained results in $\mathcal{N} = 4$ supersymmetric Yang-Mills theory. We obtain the $N=2$ Mellin moment of the bulk region of the EEC using momentum sum rules. Finally, we obtain the first resummation of the EEC in the back-to-back limit at N$^3$LL$^\prime$ accuracy, resulting in a factor of $\sim 4$ reduction of uncertainties in the peak region compared to N$^3$LL predictions., Comment: 32 pages, many wonderful figures, 3 appendices, 7 ancillary files. v2: Journal version. Added regulator independent jet functions, comparisons with OPAL data and O(as^3) numerical fixed order results
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- 2020
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10. TMD Fragmentation Functions at N$^3$LO
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Ebert, Markus A., Mistlberger, Bernhard, and Vita, Gherardo
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High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
We compute the unpolarized quark and gluon transverse-momentum dependent fragmentation functions (TMDFFs) at next-to-next-to-next-to-leading order (N$^3$LO) in perturbative QCD. The calculation is based on a relation between the TMDFF and the limit of the semi-inclusive deep inelastic scattering cross section where all final-state radiation becomes collinear to the detected hadron. The required cross section is obtained by analytically continuing our recent computation of the Drell-Yan and Higgs boson production cross section at N$^3$LO expanded around the limit of all final-state radiation becoming collinear to one of the initial states. Our results agree with a recent independent calculation by Luo et al., Comment: 20 pages + appendices, 3 figures, 6 ancillary files; v2: journal version
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- 2020
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11. Drell-Yan $q_T$ Resummation of Fiducial Power Corrections at N$^3$LL
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Ebert, Markus A., Michel, Johannes K. L., Stewart, Iain W., and Tackmann, Frank J.
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High Energy Physics - Phenomenology ,High Energy Physics - Experiment ,Nuclear Theory - Abstract
We consider Drell-Yan production $pp\to V^* X \to L X$ at small $q_T \ll Q$. Experimental measurements require fiducial cuts on the leptonic state $L$, which introduce enhanced, linear power corrections in $q_T/Q$. We show that they can be unambiguously predicted from factorization, and resummed to the same order as the leading-power contribution. We thus obtain predictions for the fiducial $q_T$ spectrum to N3LL and next-to-leading-power in $q_T/Q$. Matching to full NNLO ($\alpha_s^2$), we find that the linear power corrections are indeed the dominant ones, and the remaining fixed-order corrections become almost negligible below $q_T \lesssim 40$ GeV. We also discuss the implications for more complicated observables, and provide predictions for the fiducial $\phi^*$ spectrum at N3LL+NNLO. We find excellent agreement with ATLAS and CMS measurements of $q_T$ and $\phi^*$. We also consider the $p_T^\ell$ spectrum. We show that it develops leptonic power corrections in $q_T/(Q - 2p_T^\ell)$, which diverge near the Jacobian peak $p_T^\ell \sim Q/2$ and must be kept to all powers to obtain a meaningful result there. Doing so, we obtain for the first time an analytically resummed result for the $p_T^\ell$ spectrum around the Jacobian peak at N3LL+NNLO. Our method is based on performing a complete tensor decomposition for hadronic and leptonic tensors. In practice this is equivalent to often-used recoil prescriptions, for which our results now provide rigorous, formal justification. Our tensor decomposition yields nine Lorentz-scalar hadronic structure functions, which directly map onto the commonly used angular coefficients, but also holds for arbitrary leptonic final states. In particular, for suitably defined Born-projected leptons it still yields a LO-like angular decomposition even when including QED final-state radiation. We also discuss the application to $q_T$ subtractions., Comment: 81 pages + appendices, beautiful figures [abstract abridged]; v2: more beautiful figures (illustration of Born lepton projection, comparisons to normalized CMS spectra); v3: journal version (added figure with uncertainty breakdown)
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- 2020
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12. Parton distributions and lattice QCD calculations: toward 3D structure
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Constantinou, Martha, Courtoy, Aurore, Ebert, Markus A., Engelhardt, Michael, Giani, Tommaso, Hobbs, Tim, Hou, Tie-Jiun, Kusina, Aleksander, Kutak, Krzysztof, Liang, Jian, Lin, Huey-Wen, Liu, Keh-Fei, Liuti, Simonetta, Mezrag, Cédric, Nadolsky, Pavel, Nocera, Emanuele R., Olness, Fred, Qiu, Jian-Wei, Radici, Marco, Radyushkin, Anatoly, Rajan, Abha, Rogers, Ted, Rojo, Juan, Schierholz, Gerrit, Yuan, C. -P., Zhang, Jian-Hui, and Zhang, Rui
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice - Abstract
The strong force which binds hadrons is described by the theory of Quantum Chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a comprehensive understanding of the structure of hadrons. Within the context of the QCD parton picture, the Parton Distribution Functions (PDFs) have been remarkably successful in describing a wide variety of processes. However, these PDFs have generally been confined to the description of collinear partons within the hadron. New experiments and facilities provide the opportunity to additionally explore the transverse structure of hadrons which is described by Generalized Parton Distributions (GPDs) and Transverse Momentum Dependent Parton Distribution Functions (TMD PDFs). In our previous review, we compared and contrasted the two main approaches used to determine the collinear PDFs: the first based on perturbative QCD factorization theorems, and the second based on lattice QCD calculations. In the present report, we provide an update of recent progress on the collinear PDFs, and also expand the scope to encompass the generalized PDFs (GPDs and TMD PDFs). We review the current state of the various calculations, and consider what new data might be available in the near future. We also examine how a shared effort can foster dialog between the PDF and Lattice QCD communities, and yield improvements for these generalized PDFs., Comment: 2020 PDFLattice Report, 64 pages, 34 figures
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- 2020
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13. Collinear expansion for color singlet cross sections
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Ebert, Markus A., Mistlberger, Bernhard, and Vita, Gherardo
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High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO., Comment: 39 pages, 1 awesome figure; v2: journal version
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- 2020
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14. Transverse momentum dependent PDFs at N$^3$LO
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Ebert, Markus A., Mistlberger, Bernhard, and Vita, Gherardo
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High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
We compute the quark and gluon transverse momentum dependent parton distribution functions at next-to-next-to-next-to-leading order (N$^3$LO) in perturbative QCD. Our calculation is based on an expansion of the differential Higgs boson and Drell-Yan production cross sections about their collinear limit. This method allows us to employ cutting edge techniques for the computation of cross sections to extract the universal building blocks in question. The corresponding perturbative matching kernels for all channels are expressed in terms of simple harmonic polylogarithms up to weight five. As a byproduct, we confirm a previous computation of the soft function for transverse momentum factorization at N$^3$LO. Our results are the last missing ingredient to extend the $q_T$ subtraction methods to N$^3$LO and to obtain resummed $q_T$ spectra at N$^3$LL$^\prime$ accuracy both for gluon as well as for quark initiated processes., Comment: 12 pages + appendices, 4 awesome figures, important ancillary files. v2: journal version
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- 2020
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15. N-jettiness beam functions at N3LO
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Ebert, Markus, Mistlberger, Bernhard, and Vita, Gherardo
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High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
We present the first complete calculation for the quark and gluon $N$-jettiness ($\Tau_N$) beam functions at next-to-next-to-next-to-leading order (N$^3$LO) in perturbative QCD. Our calculation is based on an expansion of the differential Higgs boson and Drell-Yan production cross sections about their collinear limit. This method allows us to employ cutting edge techniques for the computation of cross sections to extract the universal building blocks in question. The class of functions appearing in the matching coefficents for all channels includes iterated integrals with non-rational kernels, thus going beyond the one of harmonic polylogarithms. Our results are a key step in extending the $\Tau_N$ subtraction methods to N$^3$LO, and to resum $\Tau_N$ distributions at N$^3$LL$^\prime$ accuracy both for quark as well as for gluon initiated processes., Comment: 7 wonderful figures
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- 2020
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16. One-loop Matching for Spin-Dependent Quasi-TMDs
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Ebert, Markus A., Schindler, Stella T., Stewart, Iain W., and Zhao, Yong
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice ,Nuclear Theory - Abstract
Transverse momentum dependent parton distribution functions (TMDPDFs) provide a unique probe of the three-dimensional spin structure of hadrons. We construct spin-dependent quasi-TMDPDFs that are amenable to lattice QCD calculations and that can be used to determine spin-dependent TMDPDFs. We calculate the short-distance coefficients connecting spin-dependent TMDPDFs and quasi-TMDPDFs at one-loop order. We find that the helicity and transversity distributions have the same coefficient as the unpolarized TMDPDF. We also argue that the same is true for pretzelosity and that this spin universality of the matching will hold to all orders in $\alpha_s$. Thus, it is possible to calculate ratios of these distributions as a function of longitudinal momentum and transverse position utilizing simpler Wilson line paths than have previously been considered., Comment: 24 pages, 4 figures
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- 2020
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17. Impact of Isolation and Fiducial Cuts on $q_T$ and N-Jettiness Subtractions
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Ebert, Markus A. and Tackmann, Frank J.
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High Energy Physics - Phenomenology - Abstract
Kinematic selection cuts and isolation requirements are a necessity in experimental measurements for identifying prompt leptons and photons that originate from the hard-interaction process of interest. We analyze how such cuts affect the application of the $q_T$ and $N$-jettiness subtraction methods for fixed-order calculations. We consider both fixed-cone and smooth-cone isolation methods. We find that kinematic selection and isolation cuts both induce parametrically enhanced power corrections with considerably slower convergence compared to the standard power corrections that are already present in inclusive cross sections without additional cuts. Using analytic arguments at next-to-leading order we derive their general scaling behavior as a function of the subtraction cutoff. We also study their numerical impact for the case of gluon-fusion Higgs production in the $H\to\gamma\gamma$ decay mode and for $pp\to\gamma\gamma$ direct diphoton production. We find that the relative enhancement of the additional cut-induced power corrections tends to be more severe for $q_T$, where it can reach an order of magnitude or more, depending on the choice of parameters and subtraction cutoffs. We discuss how all such cuts can be incorporated without causing additional power corrections by implementing the subtractions differentially rather than through a global slicing method. We also highlight the close relation of this formulation of the subtractions to the projection-to-Born method., Comment: 27 pages, 4 figures; v2: minor changes, journal version
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- 2019
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18. Renormalization and Matching for the Collins-Soper Kernel from Lattice QCD
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Ebert, Markus A., Stewart, Iain W., and Zhao, Yong
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice ,Nuclear Theory - Abstract
The Collins-Soper kernel, which governs the energy evolution of transverse-momentum dependent parton distribution functions (TMDPDFs), is required to accurately predict Drell-Yan like processes at small transverse momentum, and is a key ingredient for extracting TMDPDFs from experiment. Earlier we proposed a method to calculate this kernel from ratios of the so-called quasi-TMDPDFs determined with lattice QCD, which are defined as hadronic matrix elements of staple-shaped Euclidean Wilson line operators. Here we provide the one-loop renormalization of these operators in a regularization-independent momentum subtraction (RI$^\prime$/MOM) scheme, as well as the conversion factor from the RI$^\prime$/MOM-renormalized quasi-TMDPDF to the $\overline{\rm MS}$ scheme. We also propose a procedure for calculating the Collins-Soper kernel directly from position space correlators, which simplifies the lattice determination., Comment: 27 pages + appendices, 5 figures; v2: journal version
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- 2019
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19. A Toolbox for $q_T$ and $0$-Jettiness Subtractions at N$^3$LO
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Billis, Georgios, Ebert, Markus A., Michel, Johannes K. L., and Tackmann, Frank J.
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High Energy Physics - Phenomenology - Abstract
We derive the leading-power singular terms at three loops for both $q_T$ and 0-jettiness, $\cal{T}_0$, for generic color-singlet processes. Our results provide the complete set of differential subtraction terms for $q_T$ and $\cal{T}_0$ subtractions at N$^3$LO, which are an important ingredient for matching N$^3$LO calculations with parton showers. We obtain the full three-loop structure of the relevant beam and soft functions, which are necessary ingredients for the resummation of $q_T$ and $\cal{T}_0$ at N$^3$LL$'$ and N$^4$LL order, and which constitute important building blocks in other contexts as well. The nonlogarithmic boundary coefficients of the beam functions, which contribute to the integrated subtraction terms, are not yet fully known at three loops. By exploiting consistency relations between different factorization limits, we derive results for the $q_T$ and $\cal{T}_0$ beam function coefficients at N$^3$LO in the $z\to 1$ threshold limit, and we also estimate the size of the unknown terms beyond threshold., Comment: 37 pages + appendices, 8 figures; v2: minor changes, journal version
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- 2019
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20. Significance of temperature as a key driver in ZVI PRB applications for PCE degradation
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Metzgen, Adrian D., Dahmke, Andreas, and Ebert, Markus
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- 2023
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21. Erratum to: Factorization for azimuthal asymmetries in SIDIS at next-to-leading power
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Ebert, Markus A., Gao, Anjie, and Stewart, Iain W.
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- 2023
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22. Towards Quasi-Transverse Momentum Dependent PDFs Computable on the Lattice
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Ebert, Markus A., Stewart, Iain W., and Zhao, Yong
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High Energy Physics - Phenomenology - Abstract
Transverse momentum dependent parton distributions (TMDPDFs) which appear in factorized cross sections involve infinite Wilson lines with edges on or close to the light-cone. Since these TMDPDFs are not directly calculable with a Euclidean path integral in lattice QCD, we study the construction of quasi-TMDPDFs with finite-length spacelike Wilson lines that are amenable to such calculations. We define an infrared consistency test to determine which quasi-TMDPDF definitions are related to the TMDPDF, by carrying out a one-loop study of infrared logarithms of transverse position $b_T\sim \Lambda_{\rm QCD}^{-1}$, which must agree between them. This agreement is a necessary condition for the two quantities to be related by perturbative matching. TMDPDFs necessarily involve combining a hadron matrix element, which nominally depends on a single light-cone direction, with soft matrix elements that necessarily depend on two light-cone directions. We show at one loop that the simplest definitions of the quasi hadron matrix element, the quasi soft matrix element, and the resulting quasi-TMDPDF all fail the infrared consistency test. Ratios of impact parameter quasi-TMDPDFs still provide nontrivial information about the TMDPDFs, and are more robust since the soft matrix elements cancel. We show at one loop that such quasi ratios can be matched to ratios of the corresponding TMDPDFs. We also introduce a modified "bent" quasi soft matrix element which yields a quasi-TMDPDF that passes the consistency test with the TMDPDF at one loop, and discuss potential issues at higher orders., Comment: 39 pages + appendices, 13 figures; v2: journal version
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- 2019
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23. Subleading Power Rapidity Divergences and Power Corrections for $q_T$
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Ebert, Markus A., Moult, Ian, Stewart, Iain W., Tackmann, Frank J., Vita, Gherardo, and Zhu, Hua Xing
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High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
A number of important observables exhibit logarithms in their perturbative description that are induced by emissions at widely separated rapidities. These include transverse-momentum ($q_T$) logarithms, logarithms involving heavy-quark or electroweak gauge boson masses, and small-$x$ logarithms. In this paper, we initiate the study of rapidity logarithms, and the associated rapidity divergences, at subleading order in the power expansion. This is accomplished using the soft collinear effective theory (SCET). We discuss the structure of subleading-power rapidity divergences and how to consistently regulate them. We introduce a new pure rapidity regulator and a corresponding $\overline{\rm MS}$-like scheme, which handles rapidity divergences while maintaining the homogeneity of the power expansion. We find that power-law rapidity divergences appear at subleading power, which give rise to derivatives of parton distribution functions. As a concrete example, we consider the $q_T$ spectrum for color-singlet production, for which we compute the complete $q_T^2/Q^2$ suppressed power corrections at $\mathcal{O}(\alpha_s)$, including both logarithmic and nonlogarithmic terms. Our results also represent an important first step towards carrying out a resummation of subleading-power rapidity logarithms., Comment: 40 pages + appendices, 3 figures; v2: TMD collaboration included in acknowledgement; v3: minor changes, journal version
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- 2018
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24. Determining the Nonperturbative Collins-Soper Kernel From Lattice QCD
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Ebert, Markus A., Stewart, Iain W., and Zhao, Yong
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High Energy Physics - Phenomenology ,High Energy Physics - Lattice ,Nuclear Theory - Abstract
At small transverse momentum $q_T$, transverse-momentum dependent parton distribution functions (TMDPDFs) arise as genuinely nonperturbative objects that describe Drell-Yan like processes in hadron collisions as well as semi-inclusive deep-inelastic scattering. TMDPDFs naturally depend on the hadron momentum, and the associated evolution is determined by the Collins-Soper equation. For $q_T \sim \Lambda_\mathrm{QCD}$ the corresponding evolution kernel (or anomalous dimension) is nonperturbative and must be determined as an independent ingredient in order to relate TMDPDFs at different scales. We propose a method to extract this kernel using lattice QCD and the Large-Momentum Effective Theory, where the physical TMD correlation involving light-like paths is approximated by a quasi TMDPDF, defined using equal-time correlation functions with a large-momentum hadron state. The kernel is determined from a ratio of quasi TMDPDFs extracted at different hadron momenta., Comment: 9 pages, 2 figures; v2: extended the review of TMDPDF commonalities, version submitted to PRD; v3: minor changes, journal version
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- 2018
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25. Power Corrections for N-Jettiness Subtractions at ${\cal O}(\alpha_s)$
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Ebert, Markus A., Moult, Ian, Stewart, Iain W., Tackmann, Frank J., Vita, Gherardo, and Zhu, Hua Xing
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High Energy Physics - Phenomenology - Abstract
We continue the study of power corrections for $N$-jettiness subtractions by analytically computing the complete next-to-leading power corrections at $\cal{O}(\alpha_s)$ for color-singlet production. This includes all nonlogarithmic terms and all partonic channels for Drell-Yan and gluon-fusion Higgs production. These terms are important to further improve the numerical performance of the subtractions, and to better understand the structure of power corrections beyond their leading logarithms, in particular their universality. We emphasize the importance of computing the power corrections differential in both the invariant mass, $Q$, and rapidity, $Y$, of the color-singlet system, which is necessary to account for the rapidity dependence in the subtractions. This also clarifies apparent disagreements in the literature. Performing a detailed numerical study, we find excellent agreement of our analytic results with a previous numerical extraction., Comment: 59 pages, 11 figures; v2: minor changes, journal version
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- 2018
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26. Power corrections for N-jettiness subtractions at Oαs
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Ebert, Markus A, Moult, Ian, Stewart, Iain W, Tackmann, Frank J, Vita, Gherardo, and Zhu, Hua Xing
- Subjects
Mathematical Physics ,Particle and High Energy Physics ,Mathematical Sciences ,Physical Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Quantum Physics ,Nuclear & Particles Physics ,Mathematical physics ,Nuclear and plasma physics ,Particle and high energy physics - Abstract
Abstract : We continue the study of power corrections for N -jettiness subtractions by analytically computing the complete next-to-leading power corrections at $$ \mathcal{O}\left({\alpha}_s\right) $$ O α s for colorsinglet production. This includes all nonlogarithmic terms and all partonic channels for Drell-Yan and gluon-fusion Higgs production. These terms are important to further improve the numerical performance of the subtractions, and to better understand the structure of power corrections beyond their leading logarithms, in particular their universality. We emphasize the importance of computing the power corrections differential in both the invariant mass, Q, and rapidity, Y, of the color-singlet system, which is necessary to account for the rapidity dependence in the subtractions. This also clarifies apparent disagreements in the literature. Performing a detailed numerical study, we find excellent agreement of our analytic results with a previous numerical extraction.
- Published
- 2018
27. Power corrections for N-jettiness subtractions at $$ \mathcal{O}\left({\alpha}_s\right) $$
- Author
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Ebert, Markus A, Moult, Ian, Stewart, Iain W, Tackmann, Frank J, Vita, Gherardo, and Zhu, Hua Xing
- Subjects
Nuclear & Particles Physics ,Mathematical Physics ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Quantum Physics - Abstract
Abstract We continue the study of power corrections for N -jettiness subtractions by analytically computing the complete next-to-leading power corrections at $$ \mathcal{O}\left({\alpha}_s\right) $$ O α s for colorsinglet production. This includes all nonlogarithmic terms and all partonic channels for Drell-Yan and gluon-fusion Higgs production. These terms are important to further improve the numerical performance of the subtractions, and to better understand the structure of power corrections beyond their leading logarithms, in particular their universality. We emphasize the importance of computing the power corrections differential in both the invariant mass, Q, and rapidity, Y, of the color-singlet system, which is necessary to account for the rapidity dependence in the subtractions. This also clarifies apparent disagreements in the literature. Performing a detailed numerical study, we find excellent agreement of our analytic results with a previous numerical extraction.
- Published
- 2018
28. Resummation Improved Rapidity Spectrum for Gluon Fusion Higgs Production
- Author
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Ebert, Markus A., Michel, Johannes K. L., and Tackmann, Frank J.
- Subjects
High Energy Physics - Phenomenology - Abstract
Gluon-induced processes such as Higgs production typically exhibit large perturbative corrections. These partially arise from large virtual corrections to the gluon form factor, which at timelike momentum transfer contains Sudakov logarithms evaluated at negative arguments $\ln^2(-1) = -\pi^2$. It has been observed that resumming these terms in the timelike form factor leads to a much improved perturbative convergence for the total cross section. We discuss how to consistently incorporate the resummed form factor into the perturbative predictions for generic cross sections differential in the Born kinematics, including in particular the Higgs rapidity spectrum. We verify that this indeed improves the perturbative convergence, leading to smaller and more reliable perturbative uncertainties, and that this is not affected by cancellations between resummed and unresummed contributions. Combining both fixed-order and resummation uncertainties, the perturbative uncertainty for the total cross section at N$^3$LO$+$N$^3$LL$^\prime_\varphi$ is about a factor of two smaller than at N$^3$LO. The perturbative uncertainty of the rapidity spectrum at NNLO$+$NNLL$^\prime_\varphi$ is similarly reduced compared to NNLO. We also study the analogous resummation for quark-induced processes, namely Higgs production through bottom quark annihilation and the Drell-Yan rapidity spectrum. For the former the resummation leads to a small improvement, while for the latter it confirms the already small uncertainties of the fixed-order predictions., Comment: 30 pages + 17 pages in Appendices, 10 figures; v2: journal version; references added, discussed individual partonic channels for Drell-Yan
- Published
- 2017
- Full Text
- View/download PDF
29. Resummation of Transverse Momentum Distributions in Distribution Space
- Author
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Ebert, Markus A. and Tackmann, Frank J.
- Subjects
High Energy Physics - Phenomenology - Abstract
Differential spectra in observables that resolve additional soft or collinear QCD emissions exhibit Sudakov double logarithms in the form of logarithmic plus distributions. Important examples are the total transverse momentum $q_T$ in color-singlet production, N-jettiness (with thrust or beam thrust as special cases), but also jet mass and more complicated jet substructure observables. The all-order logarithmic structure of such distributions is often fully encoded in differential equations, so-called (renormalization group) evolution equations. We introduce a well-defined technique of distributional scale setting, which allows one to treat logarithmic plus distributions like ordinary logarithms when solving these differential equations. In particular, this allows one (through canonical scale choices) to minimize logarithmic contributions in the boundary terms of the solution, and to obtain the full distributional logarithmic structure from the solution's evolution kernel directly in distribution space. We apply this technique to the $q_T$ distribution, where the two-dimensional nature of convolutions leads to additional difficulties (compared to one-dimensional cases like thrust), and for which the resummation in distribution (or momentum) space has been a long-standing open question. For the first time, we show how to perform the RG evolution fully in momentum space, thereby directly resumming the logarithms $[\ln^n(q_T^2/Q^2)/q_T^2]_+$ appearing in the physical $q_T$ distribution. The resummation accuracy is then solely determined by the perturbative expansion of the associated anomalous dimensions., Comment: 58 pages + 12 pages in Appendices, 2 figures; v2: minor changes, journal version
- Published
- 2016
- Full Text
- View/download PDF
30. Exploiting jet binning to identify the initial state of high-mass resonances
- Author
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Ebert, Markus A., Liebler, Stefan, Moult, Ian, Stewart, Iain W., Tackmann, Frank J., Tackmann, Kerstin, and Zeune, Lisa
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Experiment - Abstract
If a new high-mass resonance is discovered at the Large Hadron Collider, model-independent techniques to identify the production mechanism will be crucial to understand its nature and effective couplings to Standard Model particles. We present a powerful and model-independent method to infer the initial state in the production of any high-mass color-singlet system by using a tight veto on accompanying hadronic jets to divide the data into two mutually exclusive event samples (jet bins). For a resonance of several hundred GeV, the jet binning cut needed to discriminate quark and gluon initial states is in the experimentally accessible range of several tens of GeV. It also yields comparable cross sections for both bins, making this method viable already with the small event samples available shortly after a discovery. Theoretically, the method is made feasible by utilizing an effective field theory setup to compute the jet cut dependence precisely and model independently and to systematically control all sources of theoretical uncertainties in the jet binning, as well as their correlations. We use a 750 GeV scalar resonance as an example to demonstrate the viability of our method., Comment: 6 pages, 2 figures, v2: journal version
- Published
- 2016
- Full Text
- View/download PDF
31. Jettiness formulation of the MiNNLOPS method.
- Author
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Ebert, Markus, Rottoli, Luca, Wiesemann, Marius, Zanderighi, Giulia, and Zanoli, Silvia
- Abstract
We present a new formulation of the MiNNLO
PS method to match NNLO QCD calculations with parton showers by using jettiness as a resummation variable. The full derivation for colour-singlet processes is presented using 0-jettiness starting from the NNLL′ resummation formula. We show phenomenological results for Drell-Yan and Higgs-boson production at the LHC and compare our predictions to ATLAS and CMS data. Differences to the original MiNNLOPS formulation using the transverse momentum of the colour singlet as resummation variable are discussed. We further present a comparison of MiNNLOPS predictions with Geneva. Finally, we extend the formulation of the MiNNLOPS method to 1-jettiness which is applicable to processes with a colour singlet plus one jet in the final state. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
32. Experimental process parameterization of a 3D site-scale model on effects of a compressed air intrusion into a shallow aquifer
- Author
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Berta, Marton, Ebert, Markus, Schäfer, Dirk, and Dethlefsen, Frank
- Published
- 2017
- Full Text
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33. Uncertainties of geochemical codes and thermodynamic databases for predicting the impact of carbon dioxide on geologic formations
- Author
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Haase, Christoph, Ebert, Markus, and Dethlefsen, Frank
- Published
- 2016
- Full Text
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34. Rapid Consumption of Dihydrogen Injected into a Shallow Aquifer by Ecophysiologically Different Microbes.
- Author
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Keller, Nina S., Lüders, Klas, Hornbruch, Götz, Birnstengel, Susann, Vogt, Carsten, Ebert, Markus, Kallies, René, Dahmke, Andreas, and Richnow, Hans H.
- Published
- 2024
- Full Text
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35. Energy storage in the geological subsurface: dimensioning, risk analysis and spatial planning: the ANGUS+ project
- Author
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Kabuth, Alina, Dahmke, Andreas, Beyer, Christof, Bilke, Lars, Dethlefsen, Frank, Dietrich, Peter, Duttmann, Rainer, Ebert, Markus, Feeser, Volker, Görke, Uwe-Jens, Köber, Ralf, Rabbel, Wolfgang, Schanz, Tom, Schäfer, Dirk, Würdemann, Hilke, and Bauer, Sebastian
- Published
- 2017
- Full Text
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36. Uncertainty in geochemical modelling of CO2 and calcite dissolution in NaCl solutions due to different modelling codes and thermodynamic databases
- Author
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Haase, Christoph, Dethlefsen, Frank, Ebert, Markus, and Dahmke, Andreas
- Published
- 2013
- Full Text
- View/download PDF
37. Monitoring Approaches for Detecting and Evaluating CO2 and Formation Water Leakages into Near-surface Aquifers
- Author
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Dethlefsen, Frank, Köber, Ralf, Schäfer, Dirk, Hagrey, Said Attia al, Hornbruch, Götz, Ebert, Markus, Beyer, Matthias, Großmann, Jochen, and Dahmke, Andreas
- Published
- 2013
- Full Text
- View/download PDF
38. Temperature Effects on PCE Degradation on ZVI in Column Experiments with Deionized Water
- Author
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Metzgen, Adrian D., primary, Dahmke, Andreas, additional, and Ebert, Markus, additional
- Published
- 2022
- Full Text
- View/download PDF
39. Disentangling long and short distances in momentum-space TMDs
- Author
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Ebert, Markus A., primary, Michel, Johannes K. L., additional, Stewart, Iain W., additional, and Sun, Zhiquan, additional
- Published
- 2022
- Full Text
- View/download PDF
40. Factorization connecting continuum & lattice TMDs
- Author
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Massachusetts Institute of Technology. Center for Theoretical Physics, Ebert, Markus A., Schindler, Stella T., Stewart, Iain W., Zhao, Yong, Massachusetts Institute of Technology. Center for Theoretical Physics, Ebert, Markus A., Schindler, Stella T., Stewart, Iain W., and Zhao, Yong
- Published
- 2022
41. Disentangling long and short distances in momentum-space TMDs
- Author
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Massachusetts Institute of Technology. Center for Theoretical Physics, Ebert, Markus A., Michel, Johannes K. L., Stewart, Iain W., Sun, Zhiquan, Massachusetts Institute of Technology. Center for Theoretical Physics, Ebert, Markus A., Michel, Johannes K. L., Stewart, Iain W., and Sun, Zhiquan
- Published
- 2022
42. Factorization for azimuthal asymmetries in SIDIS at next-to-leading power
- Author
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Massachusetts Institute of Technology. Center for Theoretical Physics, Ebert, Markus A., Gao, Anjie, Stewart, Iain W., Massachusetts Institute of Technology. Center for Theoretical Physics, Ebert, Markus A., Gao, Anjie, and Stewart, Iain W.
- Abstract
Differential measurements of the semi-inclusive deep inelastic scattering (SIDIS) process with polarized beams provide important information on the three-dimensional structure of hadrons. Among the various observables are azimuthal asymmetries that start at subleading power, and which give access to novel transverse momentum dependent distributions (TMDs). Theoretical predictions for these distributions are currently based on the parton model rather than a rigorous factorization based analysis. Working under the assumption that leading power Glauber interactions do not spoil factorization at this order, we use the Soft Collinear Effective Theory to derive a complete factorization formula for power suppressed hard scattering effects in SIDIS. This yields generalized definitions of the TMDs that depend on two longitudinal momentum fractions (one of them only relevant beyond tree level), and a complete proof that only the same leading power soft function appears and can be absorbed into the TMD distributions at this order. We also show that perturbative corrections can be accounted for with only one new hard coefficient. Factorization formulae are given for all spin dependent structure functions which start at next-to-leading power. Prospects for improved subleading power predictions that include resummation are discussed.
- Published
- 2022
43. Factorization for azimuthal asymmetries in SIDIS at next-to-leading power
- Author
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Ebert, Markus A., primary, Gao, Anjie, additional, and Stewart, Iain W., additional
- Published
- 2022
- Full Text
- View/download PDF
44. Factorization connecting continuum & lattice TMDs
- Author
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Ebert, Markus A., primary, Schindler, Stella T., additional, Stewart, Iain W., additional, and Zhao, Yong, additional
- Published
- 2022
- Full Text
- View/download PDF
45. Suitability of Existing Numerical Model Codes and Thermodynamic Databases for the Prognosis of Calcite Dissolution Processes in Near-Surface Sediments Due to a CO2 Leakage Investigated by Column Experiments
- Author
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Haase, Christoph, Dahmke, Andreas, Ebert, Markus, Schäfer, Dirk, and Dethlefsen, Frank
- Published
- 2014
- Full Text
- View/download PDF
46. Analytic results for Sudakov form factors in QCD
- Author
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Ebert, Markus A., primary
- Published
- 2022
- Full Text
- View/download PDF
47. Gas-phase formation during thermal energy storage in near-surface aquifers: experimental and modelling results
- Author
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Lüders, Klas, Firmbach, Linda, Ebert, Markus, Dahmke, Andreas, Dietrich, Peter, and Köber, Ralf
- Published
- 2016
- Full Text
- View/download PDF
48. Surface passivation model explains pyrite oxidation kinetics in column experiments with up to 11 bars p(O2)
- Author
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Berta, Marton, Dethlefsen, Frank, Ebert, Markus, Gundske, Karsten, and Dahmke, Andreas
- Published
- 2016
- Full Text
- View/download PDF
49. A geological database for parameterization in numerical modeling of subsurface storage in northern Germany
- Author
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Dethlefsen, Frank, Ebert, Markus, and Dahmke, Andreas
- Published
- 2014
- Full Text
- View/download PDF
50. Impacts of the use of the geological subsurface for energy storage: an investigation concept
- Author
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Bauer, Sebastian, Beyer, Christof, Dethlefsen, Frank, Dietrich, Peter, Duttmann, Rainer, Ebert, Markus, Feeser, Volker, Görke, Uwe, Köber, Ralf, Kolditz, Olaf, Rabbel, Wolfgang, Schanz, Tom, Schäfer, Dirk, Würdemann, Hilke, and Dahmke, Andreas
- Published
- 2013
- Full Text
- View/download PDF
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