| Records |
| Author |
Ramirez-Uribe, S.; Hernandez-Pinto, R.J.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J. |
| Title |
Universal opening of four-loop scattering amplitudes to trees |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
04 |
Issue |
4 |
Pages |
129 - 22pp |
| Keywords |
Duality in Gauge Field Theories; Perturbative QCD; Scattering Amplitudes |
| Abstract |
The perturbative approach to quantum field theories has made it possible to obtain incredibly accurate theoretical predictions in high-energy physics. Although various techniques have been developed to boost the efficiency of these calculations, some ingredients remain specially challenging. This is the case of multiloop scattering amplitudes that constitute a hard bottleneck to solve. In this paper, we delve into the application of a disruptive technique based on the loop-tree duality theorem, which is aimed at an efficient computation of such objects by opening the loops to nondisjoint trees. We study the multiloop topologies that first appear at four loops and assemble them in a clever and general expression, the (NMLT)-M-4 universal topology. This general expression enables to open any scattering amplitude of up to four loops, and also describes a subset of higher order configurations to all orders. These results confirm the conjecture of a factorized opening in terms of simpler known subtopologies, which also determines how the causal structure of the entire loop amplitude is characterized by the causal structure of its subtopologies. In addition, we confirm that the loop-tree duality representation of the (NMLT)-M-4 universal topology is manifestly free of noncausal thresholds, thus pointing towards a remarkably more stable numerical implementation of multiloop scattering amplitudes. |
| Address |
[Ramirez-Uribe, Selomit; Rodrigo, German; Sborlini, German F. R.; Bobadilla, William J. Torres] Univ Valencia, Inst Fis Corpuscular, CSIC, Parc Cient, E-46980 Valencia, Spain, Email: norma.selomit.ramirez@ific.uv.es; |
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Springer |
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English |
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1029-8479 |
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Conference |
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| Notes |
WOS:000641467800001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4787 |
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| Author |
Hansen, M.T.; Romero-Lopez, F.; Sharpe, S.R. |
| Title |
Decay amplitudes to three hadrons from finite-volume matrix elements |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
04 |
Issue |
4 |
Pages |
113 - 44pp |
| Keywords |
Lattice QCD; Kaon Physics |
| Abstract |
We derive relations between finite-volume matrix elements and infinite-volume decay amplitudes, for processes with three spinless, degenerate and either identical or non-identical particles in the final state. This generalizes the Lellouch-Luscher relation for two-particle decays and provides a strategy for extracting three-hadron decay amplitudes using lattice QCD. Unlike for two particles, even in the simplest approximation, one must solve integral equations to obtain the physical decay amplitude, a consequence of the nontrivial finite-state interactions. We first derive the result in a simplified theory with three identical particles, and then present the generalizations needed to study phenomenologically relevant three-pion decays. The specific processes we discuss are the CP-violating K -> 3 pi weak decay, the isospin-breaking eta -> 3 pi QCD transition, and the electromagnetic gamma (*) -> 3 pi amplitudes that enter the calculation of the hadronic vacuum polarization contribution to muonic g – 2. |
| Address |
[Hansen, Maxwell T.] Univ Edinburgh, Sch Phys & Astron, Higgs Ctr Theoret Phys, Edinburgh EH9 3FD, Midlothian, Scotland, Email: maxwell.hansen@ed.ac.uk; |
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Springer |
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English |
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1029-8479 |
ISBN |
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Expedition |
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Conference |
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| Notes |
WOS:000640574400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4789 |
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| Author |
LHCb Collaboration (Aaij, R. et al); Henry, L.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
| Title |
Observation of the decay Lambda b0 -> chi(c1)p pi(-) |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
05 |
Issue |
5 |
Pages |
095 - 21pp |
| Keywords |
B physics; Branching fraction; Hadron-Hadron scattering (experiments); QCD; Quarkonium |
| Abstract |
The Cabibbo-suppressed decay Lambda b0</mml:msubsup>-> chi (c1)p(-) is observed for the first time using data from proton-proton collisions corresponding to an integrated luminosity of 6 fb(-1), collected with the LHCb detector at a centre-of-mass energy of 13 TeV. Evidence for the Lambda b0</mml:msubsup>-> chi (c2)p(-) decay is also found. Using the Lambda b0</mml:msubsup>-> chi (c1)pK(-) decay as normalisation channel, the ratios of branching fractions are measured to be<disp-formula id=“Equa”><mml:mtable displaystyle=“true”><mml:mtr><mml:mtd><mml:mfrac>B<mml:mfenced close=“)” open=“(”>Lambda b0</mml:msubsup>-> chi c1p pi-</mml:mfenced>B<mml:mfenced close=“)” open=“(”>Lambda b0</mml:msubsup>-> <mml:msub>chi c1pK-</mml:mfenced></mml:mfrac>=<mml:mfenced close=“)” open=“(”>6.59 +/- 1.01 +/- 0.22</mml:mfenced>x10-2,</mml:mtd></mml:mtr><mml:mtr><mml:mtd><mml:mfrac>B<mml:mfenced close=“)” open=“(”>Lambda b0 -> <mml:msub>chi c2p pi-</mml:mfenced>B<mml:mfenced close=“)” open=“(”>Lambda b0 -> <mml:msub>chi c1p pi-</mml:mfenced></mml:mfrac>=0.95 +/- 0.30 +/- 0.04 +/- 0.04,</mml:mtd></mml:mtr><mml:mtr><mml:mtd><mml:mfrac>B<mml:mfenced close=“)” open=“(”>Lambda b0 -> <mml:msub>chi c2pK-</mml:mfenced>B<mml:mfenced close=“)” open=“(”>Lambda b0 -> <mml:msub>chi c1pK-</mml:mfenced></mml:mfrac>=1.06 +/- 0.05 +/- 0.04 +/- 0.04,</mml:mtd></mml:mtr></mml:mtable><graphic position=“anchor” xmlns:xlink=“http://www.w3.org/1999/xlink” xlink:href=“13130202115658ArticleEqua.gif”></graphic></disp-formula><p id=“Par2”>where the first uncertainty is statistical, the second is systematic and the third is due to the uncertainties in the branching fractions of chi (c1,2)-> J/psi gamma decays.<fig id=“Figa” position=“anchor”><graphic position=“anchor” specific-use=“HTML” mime-subtype=“JPEG” xmlns:xlink=“http://www.w3.org/1999/xlink” xlink:href=“MediaObjects/13130202115658FigaHTML.jpg” id=“MO1”></graphic |
| Address |
[Bediaga, I.; Cruz Torres, M.; De Miranda, J. M.; Gomes, A.; Massafferri, A.; dos Reis, A. C.; Soares Lavra, L.; Tourinho Jadallah Aoude, R.] CBPF, Rio De Janeiro, Brazil, Email: maria.vieites.diaz@cern.ch |
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Springer |
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1029-8479 |
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Expedition |
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Conference |
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| Notes |
WOS:000651537500001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4837 |
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ATLAS Collaboration (Aad, G. et al); Aparisi Pozo, J.A.; Bailey, A.J.; Cabrera Urban, S.; Cardillo, F.; Castillo, F.L.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Estrada Pastor, O.; Fiorini, L.; Fullana Torregrosa, E.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Gonzalvo Rodriguez, G.R.; Guerrero Rojas, J.G.R.; Higon-Rodriguez, E.; Lacasta, C.; Lozano Bahilo, J.J.; Mamuzic, J.; Marti-Garcia, S.; Martinez Agullo, P.; Mitsou, V.A.; Moreno Llacer, M.; Navarro-Gonzalez, J.; Poveda, J.; Prades Ibañez, A.; Rodriguez Bosca, S.; Ruiz-Martinez, A.; Sabatini, P.; Salt, J.; Sayago Galvan, I.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valero, A.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M. |
| Title |
Determination of the parton distribution functions of the proton from ATLAS measurements of differential W-+/- and Z boson production in association with jets |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
07 |
Issue |
7 |
Pages |
223 - 44pp |
| Keywords |
Hadron-Hadron scattering (experiments); QCD |
| Abstract |
This article presents a new set of proton parton distribution functions, AT-LASepWZVjet20, produced in an analysis at next-to-next-to-leading order in QCD. The new data sets considered are the measurements of W+ and W- boson and Z boson production in association with jets in pp collisions at root s = 8 TeV performed by the ATLAS experiment at the LHC with integrated luminosities of 20.2 fb(-1) and 19.9 fb(-1), respectively. The analysis also considers the ATLAS measurements of differential W-+/- and Z boson production at root s = 7 TeV with an integrated luminosity of 4.6 fb(-1) and deep-inelastic-scattering data from e(+/-) p collisions at the HERA accelerator. An improved determination of the sea-quark densities at high Bjorken x is shown, while confirming a strange-quark density similar in size to the up- and down-sea-quark densities in the range x less than or similar to 0.02 found by previous ATLAS analyses. |
| Address |
[Duvnjak, D.; Jackson, P.; Kong, A. X. Y.; Oliver, J. L.; Ruggeri, T. A.; Sharma, A. S.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
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Springer |
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English |
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1029-8479 |
ISBN |
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Expedition |
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Conference |
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| Notes |
WOS:000680916500001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4936 |
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| Author |
Du, M.L.; Baru, V.; Guo, F.K.; Hanhart, C.; Meissner, U.G.; Oller, J.A.; Wang, Q. |
| Title |
Revisiting the nature of the P-c pentaquarks |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
08 |
Issue |
8 |
Pages |
157 - 50pp |
| Keywords |
QCD Phenomenology; Non-perturbative renormalization |
| Abstract |
The nature of the three narrow hidden-charm pentaquark P-c states, i.e., P-c (4312), P-c (4440) and P-c (4457), is under intense discussion since their discovery from the updated analysis of the process Lambda(0)(b) -> I ) J/psi pK(-) by LHCb. In this work we extend our previous coupled-channel approach [Phys. Rev. Lett. 124, 072001 (2020)], in which the Pc states are treated as Sigma(()(c)*()) (D) over bar (()*()) molecules, by including the Lambda(c)(D) over bar (()*()) and eta(c)p as explicit inelastic channels in addition to the J/psi p, as required by unitarity and heavy quark spin symmetry (HQSS), respectively. Since inelastic parameters are very badly constrained by the current data, three calculation schemes are considered: (a) scheme I with pure contact interactions between the elastic, i.e., Sigma(()(c)*()) (D) over bar (()*()), and inelastic channels and without the Lambda(c)(D) over bar (()*()) interactions, (b) scheme II, where the one-pion exchange (OPE) is added to scheme I, and (c) scheme III, where the Lambda(c)(D) over bar (()*()) interactions are included in addition. It is shown that to obtain cutoff independent results, OPE in the multichannel system is to be supplemented with S-wave-to-D-wave mixing contact terms. As a result, in line with our previous analysis, we demonstrate that the experimental data for the J/psi p invariant mass distribution are consistent with the interpretation of the P-c(4312) and P-c(4440)/P-c(4457) as Sigma(c)(D) over bar and Sigma(c)(D) over bar* hadronic molecules, respectively, and that the data show clear evidence for a new narrow state, P-c(4380), identified as a Sigma(c)*(D) over bar molecule, which should exist as a consequence of HQSS. While two statistically equally good solutions are found in scheme I, only one of these solutions with the quantum numbers of the P-c (4440) and P-c (4457) being J(P) = 3/2(-) and 1/2(-), respectively, survives the requirement of regulator independence once the OPE is included. Moreover, we predict the line shapes in the elastic and inelastic channels and demonstrate that those related to the P-c (4440) and the P-c (4457) in the Sigma(()(c)*())<(D)over ( )anf eta(c)p mass distributions from Lambda(0)(b) ->( )Sigma(()(c)*()) (D) over barK(-) and Lambda(0)(b) -> eta(c)pK(-) will shed light on the quantum numbers of those states, once the data are available. We also investigate possible pentaquark signals in the Lambda(c)(D) over bar (()*()) final states. |
| Address |
[Du, Meng-Lin; Meissner, Ulf-G.] Univ Bonn, Helmholtz Inst Strahlen & Kernphys, D-53115 Bonn, Germany, Email: du@hiskp.uni-bonn.de |
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Springer |
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English |
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1029-8479 |
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Conference |
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| Notes |
WOS:000693090600001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4958 |
| Permanent link to this record |
