Address: Departamento de Física Teórica II, Facultad de Ciencias Físicas, Universidad Complutense de Madrid,
Ciudad Universitaria s/n, 28040 Madrid (Spain)
We discuss the recent Cabibbo’s proposal to measure the ππ scattering lengths combination a0 − a2... more We discuss the recent Cabibbo’s proposal to measure the ππ scattering lengths combination a0 − a2 from the cusp effect in the π 0 π 0 energy spectrum at threshold for K + → π 0 π 0 π + and KL → π 0 π 0 π 0. We estimate the theoretical uncertainty of the a0 − a2 determination at NLO in our approach and obtain that it is not smaller than 5 % for K + → π 0 π 0 π +. One gets similar theoretical uncertainties if the neutral KL → π 0 π 0 π 0 decay data below threshold are used instead. For this decay, there are very large theoretical uncertainties above threshold due to cancellations and data above threshold cannot be used to get the scattering lengths. Preprint CERN-PH-TH/2006-219, IFIC/06-37 1.
We update the CP-violating asymmetries in K^+ -> 3 pi. In particular we study Delta g_C and De... more We update the CP-violating asymmetries in K^+ -> 3 pi. In particular we study Delta g_C and Delta g_N -the asymmetries in the slope g. We emphasize its complementarity to the direct CP-violation parameter epsilon_K' and the large sensitivity to the size of the imaginary part of the octet coupling Im G_8 at lowest order in CHPT. We also give the prospects of a full calculation at next-to-leading order of this and other CP-violating asymmetries which will be presented elsewhere.
We present for first time the computation at large $q_T$ (or small $b_T$) matching coefficients o... more We present for first time the computation at large $q_T$ (or small $b_T$) matching coefficients of Transverse Momentum Dependent Parton Distribution Function (TMDPDF) for linearly polarised to the integrated gluon distribution at next-to-next-to leading order (NNLO). The computation is performed using the modified $\delta$-regulator for rapidity divergences and dimensional regularization. This TMDPDF matriz element presnts phenomenological interest in two kind of processes. The factorization of the Higgs production transverse momentum ($q_T$) distribution through gluon-gluon fusion and the quarkonium production.
The recent formulation of the factorization theorem for transverse momentum spectra in terms of w... more The recent formulation of the factorization theorem for transverse momentum spectra in terms of well-defined transverse momentum dependent distributions (TMDs), allows for a better understanding of the role of the perturbative and non-perturbative QCD contributions and their interplay. In particular, non-perturbative effects are often included both in the evolution of the TMDs and in the modeling of their scale-independent part. Using the available Drell-Yan and $Z$-production data at low and high energy we show that, for the currently available dilepton invariant mass values, the TMD evolution is driven mainly by its perturbative contribution, while the needed non-perturbative correction is scale independent. We then detail the difference between the scale dependences in the high and low boson transverse momentum regime and discuss the related theoretical errors.
We develop a method of transverse momentum dependent (TMD) operator expansion that yields the TMD... more We develop a method of transverse momentum dependent (TMD) operator expansion that yields the TMD factorization theorem on the operator level. The TMD operators are systematically ordered with respect to TMD-twist, which allows a certain separation of kinematic and genuine power corrections. The process dependence enters via the boundary conditions for the background fields. As a proof of principle, we derive the TMD factorization up to the next-to-leading power (∼ qT /Q) at the next-to-leading order for any process with two detected states. ar X iv :2 10 9. 09 77 1v 1 [ he pph ] 2 0 Se p 20 21
We present the next-to-leading order full results in Chiral Perturbation Theory for the charged K... more We present the next-to-leading order full results in Chiral Perturbation Theory for the charged Kaon K → 3π slope g CP violating asymmetries. We discuss the constraints that a measurement of these asymmetries would impose on the Standard Model results of ε K and search for new physics. We also study the kind of information that such measurement can provide on Im G8, Im (e GE) and higher order weak couplings. September 2005 Work supported in part by MEC, Spain and FEDER, European Commission (EC) Grant Nos. FPA2003-09298-C02-01 (J.P.) and FPA2004-00996 (I.S.), by Junta de Andalućıa Grant No. FQM-101 (J.P.), and by the EC RTN EURIDICE Contract No. HPRN-CT-2002-00311 (J.P. and I.S.). E.G. is indebted to the EC for the Marie Curie Fellowship No. MEIF-CT-2003501309. Invited talk given by J.P. at “XII International Conference on Quantum Chromodynamics (QCD ’05)”, 4-8 July 2005, Montpellier, France.
Disclaimer/Complaints regulations If you believe that digital publication of certain material inf... more Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible.
We discuss the recently proposed scheme for the evolution of Transverse Momentum Distributions us... more We discuss the recently proposed scheme for the evolution of Transverse Momentum Distributions using the so-called “D R ”. We discuss a new method to separate perturbative and nonperturbative effects in the analysis of the evolution of Transverse Momentum Distributions. We argue that the scheme is compatible with the standard CSS resummation approach when the running of the strong coupling is taken into account properly.
By considering semi-inclusive deep-inelastic scattering and the (complementary) qT -spectrum for ... more By considering semi-inclusive deep-inelastic scattering and the (complementary) qT -spectrum for Drell-Yan lepton pair production we derive the QCD evolution for all the leading-twist transverse momentum dependent distribution and fragmentation functions. We argue that all of those functions evolve with Q following a single evolution kernel. This kernel is independent of the underlying kinematics and it is also spin-independent. Those features hold, in impact parameter space, to all values of bT . The evolution kernel presented has all of its large logarithms resummed up next-to-nextto leading logarithmic accuracy, which is the highest possible accuracy given existing perturbative calculations. As a study case we apply this kernel to investigate the evolution of Collins function, one of the ingredients that have attracted recently much attention within the phenomenological studies of spin asymmetries. Our analysis can be readily implemented to revisit previously obtained fits that i...
At hadron colliders, the differential cross section for W production can be factorized and it is ... more At hadron colliders, the differential cross section for W production can be factorized and it is sensitive transverse momentum dependent distributions (TMD) for low boson transverse momentum. While, often, the corresponding non-perturbative QCD contributions are extrapolated from Z boson production, here we use an existing extraction (based on the code Artemide) of TMD which includes data coming from Drell–Yan and semi-inclusive deep inelastic scattering, to provide checks and predictions for the W case. Including fiducial cuts with different configurations and kinematical power corrections, we consider transverse momentum dependent cross sections within several intervals of the vector boson transverse mass. We perform the same study for the $$p_T^{W^-}/p_T^{W^+}$$ p T W - / p T W + and $$p_T^Z/p_T^W$$ p T Z / p T W distributions. We compare our predictions with recent extractions of these quantities at ATLAS and CMS and results from TeVatron. The results encourage a broader experim...
We study a transverse momentum dependent (TMD) factorization framework for the processes of dijet... more We study a transverse momentum dependent (TMD) factorization framework for the processes of dijet and heavy-meson pair production in deep-inelastic-scattering in an electron-proton collider, considering the measurement of the transverse momentum imbalance of the two hard probes in the Breit frame. For the factorization theorem we employ soft-collinear and boosted-heavy-quark effective field theories. The factorized cross-section for both processes is sensitive to gluon unpolarized and linearly polarized TMD distributions and requires the introduction of a new soft function. We calculate the new soft function here at one-loop, regulating rapidity divergences with the δ-regulator. In addition, using a factorization consistency relation and a universality argument regarding the heavy-quark jet function, we obtain the anomalous dimension of the new soft function at two and three loops.
We study the transverse-momentum spectrum of quarkonium production from single light-parton fragm... more We study the transverse-momentum spectrum of quarkonium production from single light-parton fragmentation mechanism. In the case of semi-inclusive deep inelastic scattering, we observe that there are two possible initiating processes, namely photon-gluon fusion and light-quark fragmentation. For the second case we derive the factorization theorem, which involves a new hadronic quantity: the quarkonium transverse-momentum-dependent fragmentation functions in NRQCD. We calculate their matching onto the non-perturbative long distance matrix elements at the lowest order in the strong-coupling constant, $$ \mathcal{O}\left({\alpha}_s^2\right) $$ O α s 2 . Focusing on the case of the electron-ion collider, we make a comparative phenomenological study of the two production mechanisms and find the regions of the phase space where one is dominant over the other.
We discuss the recent Cabibbo’s proposal to measure the ππ scattering lengths combination a0 − a2... more We discuss the recent Cabibbo’s proposal to measure the ππ scattering lengths combination a0 − a2 from the cusp effect in the π 0 π 0 energy spectrum at threshold for K + → π 0 π 0 π + and KL → π 0 π 0 π 0. We estimate the theoretical uncertainty of the a0 − a2 determination at NLO in our approach and obtain that it is not smaller than 5 % for K + → π 0 π 0 π +. One gets similar theoretical uncertainties if the neutral KL → π 0 π 0 π 0 decay data below threshold are used instead. For this decay, there are very large theoretical uncertainties above threshold due to cancellations and data above threshold cannot be used to get the scattering lengths. Preprint CERN-PH-TH/2006-219, IFIC/06-37 1.
We update the CP-violating asymmetries in K^+ -> 3 pi. In particular we study Delta g_C and De... more We update the CP-violating asymmetries in K^+ -> 3 pi. In particular we study Delta g_C and Delta g_N -the asymmetries in the slope g. We emphasize its complementarity to the direct CP-violation parameter epsilon_K' and the large sensitivity to the size of the imaginary part of the octet coupling Im G_8 at lowest order in CHPT. We also give the prospects of a full calculation at next-to-leading order of this and other CP-violating asymmetries which will be presented elsewhere.
We present for first time the computation at large $q_T$ (or small $b_T$) matching coefficients o... more We present for first time the computation at large $q_T$ (or small $b_T$) matching coefficients of Transverse Momentum Dependent Parton Distribution Function (TMDPDF) for linearly polarised to the integrated gluon distribution at next-to-next-to leading order (NNLO). The computation is performed using the modified $\delta$-regulator for rapidity divergences and dimensional regularization. This TMDPDF matriz element presnts phenomenological interest in two kind of processes. The factorization of the Higgs production transverse momentum ($q_T$) distribution through gluon-gluon fusion and the quarkonium production.
The recent formulation of the factorization theorem for transverse momentum spectra in terms of w... more The recent formulation of the factorization theorem for transverse momentum spectra in terms of well-defined transverse momentum dependent distributions (TMDs), allows for a better understanding of the role of the perturbative and non-perturbative QCD contributions and their interplay. In particular, non-perturbative effects are often included both in the evolution of the TMDs and in the modeling of their scale-independent part. Using the available Drell-Yan and $Z$-production data at low and high energy we show that, for the currently available dilepton invariant mass values, the TMD evolution is driven mainly by its perturbative contribution, while the needed non-perturbative correction is scale independent. We then detail the difference between the scale dependences in the high and low boson transverse momentum regime and discuss the related theoretical errors.
We develop a method of transverse momentum dependent (TMD) operator expansion that yields the TMD... more We develop a method of transverse momentum dependent (TMD) operator expansion that yields the TMD factorization theorem on the operator level. The TMD operators are systematically ordered with respect to TMD-twist, which allows a certain separation of kinematic and genuine power corrections. The process dependence enters via the boundary conditions for the background fields. As a proof of principle, we derive the TMD factorization up to the next-to-leading power (∼ qT /Q) at the next-to-leading order for any process with two detected states. ar X iv :2 10 9. 09 77 1v 1 [ he pph ] 2 0 Se p 20 21
We present the next-to-leading order full results in Chiral Perturbation Theory for the charged K... more We present the next-to-leading order full results in Chiral Perturbation Theory for the charged Kaon K → 3π slope g CP violating asymmetries. We discuss the constraints that a measurement of these asymmetries would impose on the Standard Model results of ε K and search for new physics. We also study the kind of information that such measurement can provide on Im G8, Im (e GE) and higher order weak couplings. September 2005 Work supported in part by MEC, Spain and FEDER, European Commission (EC) Grant Nos. FPA2003-09298-C02-01 (J.P.) and FPA2004-00996 (I.S.), by Junta de Andalućıa Grant No. FQM-101 (J.P.), and by the EC RTN EURIDICE Contract No. HPRN-CT-2002-00311 (J.P. and I.S.). E.G. is indebted to the EC for the Marie Curie Fellowship No. MEIF-CT-2003501309. Invited talk given by J.P. at “XII International Conference on Quantum Chromodynamics (QCD ’05)”, 4-8 July 2005, Montpellier, France.
Disclaimer/Complaints regulations If you believe that digital publication of certain material inf... more Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible.
We discuss the recently proposed scheme for the evolution of Transverse Momentum Distributions us... more We discuss the recently proposed scheme for the evolution of Transverse Momentum Distributions using the so-called “D R ”. We discuss a new method to separate perturbative and nonperturbative effects in the analysis of the evolution of Transverse Momentum Distributions. We argue that the scheme is compatible with the standard CSS resummation approach when the running of the strong coupling is taken into account properly.
By considering semi-inclusive deep-inelastic scattering and the (complementary) qT -spectrum for ... more By considering semi-inclusive deep-inelastic scattering and the (complementary) qT -spectrum for Drell-Yan lepton pair production we derive the QCD evolution for all the leading-twist transverse momentum dependent distribution and fragmentation functions. We argue that all of those functions evolve with Q following a single evolution kernel. This kernel is independent of the underlying kinematics and it is also spin-independent. Those features hold, in impact parameter space, to all values of bT . The evolution kernel presented has all of its large logarithms resummed up next-to-nextto leading logarithmic accuracy, which is the highest possible accuracy given existing perturbative calculations. As a study case we apply this kernel to investigate the evolution of Collins function, one of the ingredients that have attracted recently much attention within the phenomenological studies of spin asymmetries. Our analysis can be readily implemented to revisit previously obtained fits that i...
At hadron colliders, the differential cross section for W production can be factorized and it is ... more At hadron colliders, the differential cross section for W production can be factorized and it is sensitive transverse momentum dependent distributions (TMD) for low boson transverse momentum. While, often, the corresponding non-perturbative QCD contributions are extrapolated from Z boson production, here we use an existing extraction (based on the code Artemide) of TMD which includes data coming from Drell–Yan and semi-inclusive deep inelastic scattering, to provide checks and predictions for the W case. Including fiducial cuts with different configurations and kinematical power corrections, we consider transverse momentum dependent cross sections within several intervals of the vector boson transverse mass. We perform the same study for the $$p_T^{W^-}/p_T^{W^+}$$ p T W - / p T W + and $$p_T^Z/p_T^W$$ p T Z / p T W distributions. We compare our predictions with recent extractions of these quantities at ATLAS and CMS and results from TeVatron. The results encourage a broader experim...
We study a transverse momentum dependent (TMD) factorization framework for the processes of dijet... more We study a transverse momentum dependent (TMD) factorization framework for the processes of dijet and heavy-meson pair production in deep-inelastic-scattering in an electron-proton collider, considering the measurement of the transverse momentum imbalance of the two hard probes in the Breit frame. For the factorization theorem we employ soft-collinear and boosted-heavy-quark effective field theories. The factorized cross-section for both processes is sensitive to gluon unpolarized and linearly polarized TMD distributions and requires the introduction of a new soft function. We calculate the new soft function here at one-loop, regulating rapidity divergences with the δ-regulator. In addition, using a factorization consistency relation and a universality argument regarding the heavy-quark jet function, we obtain the anomalous dimension of the new soft function at two and three loops.
We study the transverse-momentum spectrum of quarkonium production from single light-parton fragm... more We study the transverse-momentum spectrum of quarkonium production from single light-parton fragmentation mechanism. In the case of semi-inclusive deep inelastic scattering, we observe that there are two possible initiating processes, namely photon-gluon fusion and light-quark fragmentation. For the second case we derive the factorization theorem, which involves a new hadronic quantity: the quarkonium transverse-momentum-dependent fragmentation functions in NRQCD. We calculate their matching onto the non-perturbative long distance matrix elements at the lowest order in the strong-coupling constant, $$ \mathcal{O}\left({\alpha}_s^2\right) $$ O α s 2 . Focusing on the case of the electron-ion collider, we make a comparative phenomenological study of the two production mechanisms and find the regions of the phase space where one is dominant over the other.
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Papers by Ignazio Scimemi