Measurement ofK + K − production in γγ collisions

Albrecht, H.; Ehrlichmann, H.; Harder, G.; Krüger, A.; Nau, A.; Nilsson, Anders; Nippe, A.; Oest, T.; Reidenbach, M.; Schäfer, M.; Schmidt‐Parzefall, W.; Schröder, H.; Schulz, H. D.; Sefkow, F.; Wurth, R.; Appuhn, R. D.; Drescher, A.; Hast, C.; Herrera, G.; Kolanoski, H.; Lange, A.; Lindner, A.; Mankel, R.; Scheck, H.; Schieber, M.; Schweda, G.; Spaan, B.; Walther, A.; Wegener, D.; Paulini, M.; Reim, K.; Volland, U.; Wegener, H.; Funk, W.; Stiewe, J.; Werner, S.; Ball, S.; Gabriel, J. C.; Geyer, C.; Hölscher, A.; Hofmann, W.; Hölzer, B.; Khan, S.; Spengler, J.; Britton, D.; Charlesworth, C.; Edwards, K. W.; Kapitza, H.; Krieger, P.; Kutschke, R.; MacFarlane, D. B.; McLean, K. W.; Orr, R. S.; Parsons, J. A.; Patel, P. M.; Prentice, J. D.; Seidel, S.; Tsipolitis, G.; Tzariudaki, K.; Yoon, T. S.; Ruf, T.; Schael, S.; Schubert, K. R.; Strahl, K.; Waldi, R.; Weseler, S.; Boštjančič, B.; Kernel, G.; Križan, P.; Križnič, E.; Živko, T.; Cronström, H. I.; Jönsson, L.; Babaev, A.; Danilov, M.; Droutskoy, A.; Fominykh, B.; Golutvin, A.; Gorelov, I.; Ratnikov, F.; Lubimov, V.; Rostovtsev, A.; Semenov, A.; Semenov, S.; Shevchenko, V.; Soloshenko, V.; Tchistilin, V.; Tichomirov, I.; Zaitsev, Yu.; Childers, R.; Darden, C. W.

doi:10.1007/bf01554464

Cited by 26 publications

(9 citation statements)

References 24 publications

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“…In both cases, the measured cross section and the angular distribution are largely in agreement with the previous measurements [3,4,5,6]. As an example, we show the results 1 [7] for the pp measured total cross section in fig.…”

Section: Experimental Statussupporting

confidence: 88%

Hadron pair photoproduction and the Veneziano model

Odagiri

2005

Nuclear Physics A

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We first suppose that low-energy hadron pair photoproduction reactions γ ( * ) γ ( * ) → hh are dominated by s-channel resonance contributions. Their normalization is then calculated by their correspondence with the Reggeon term in the Regge parametrization of the γh total cross sections. For the case of pp, we make use of the measured γp total cross section, and for the case of K + K − , we make use of the corresponding total cross section that is estimated using Regge factorization. For hadrons that have no such data, we can only provide rough estimation based on the additive quark rule. As an effective approach that is convenient and parameter-free, we adopt the Veneziano model in the simplest form. The model is only applicable to the region of low centre-of-mass energy. When the transverse momentum is large, perturbative QCD takes over, whereas in the Regge region, it is known that the Regge pole picture fails in photoproduction. Despite the shortcomings of the model, we find that the parameter-free amplitudes offer a sound description of the data at hand.

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Section: Experimental Statussupporting

confidence: 88%

Hadron pair photoproduction and the Veneziano model

Odagiri

2005

Nuclear Physics A

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“…In the on-shell case, available data on γγ → ππ [104][105][106][107][108][109] (in combination with γγ → KK [110][111][112][113][114][115][116]) are now sufficient to perform a partial-wave analysis [117], but such an approach appears unrealistic to control the dependence on the photon virtualities. However, approaches that exploit more comprehensively the analytic properties of the amplitude, see [54,55,118] for on-shell photons, can be extended towards the off-shell case with limited data input required to determine parameters, as demonstrated for the singly-virtual process in [56].…”

Section: Application: Two-pion Rescatteringmentioning

confidence: 99%

Dispersion relation for hadronic light-by-light scattering: two-pion contributions

Colangelo

Hoferichter

Procura

et al. 2017

J. High Energ. Phys.

371

257

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In this third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in the HLbL contribution to the anomalous magnetic moment of the muon (g − 2) µ , including a detailed discussion of the unitarity relation for arbitrary partial waves. We show that obtaining a final expression free from unphysical helicity partial waves is a subtle issue, which we thoroughly clarify. As a by-product, we obtain a set of sum rules that could be used to constrain future calculations of γ * γ * → ππ. We validate the formalism extensively using the pion-box contribution, defined by two-pion intermediate states with a pion-pole left-hand cut, and demonstrate how the full known result is reproduced when resumming the partial waves. Using dispersive fits to high-statistics data for the pion vector form factor, we provide an evaluation of the full pion box, a π-box µ = −15.9(2)×10 −11 . As an application of the partial-wave formalism, we present a first calculation of ππ-rescattering effects in HLbL scattering, with γ * γ * → ππ helicity partial waves constructed dispersively using ππ phase shifts derived from the inverse-amplitude method. In this way, the isospin-0 part of our calculation can be interpreted as the contribution of the f 0 (500) to HLbL scattering in (g − 2) µ . We argue that the contribution due to charged-pion rescattering implements corrections related to the corresponding pion polarizability and show that these are moderate. Our final result for the sum of pion-box contribution and its S-wave rescattering corrections reads a π-box µ + a ππ,π-pole LHC µ,J=0 = −24(1) × 10 −11 .

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“…However, though the λ ¼ 0 partial wave is small and the Born term plus other single-particle exchanges, as given in Eq. (24), are good enough to represent its left-hand cut, the λ ¼ 2 wave has a much bigger effect because of its interference with the large I ¼ 0; J ¼ λ ¼ 2 wave. Thus, we parametrize this wave by…”

Section: Ij ¼ 22 Channelmentioning

confidence: 99%

“…19 the γγ → K þ K − cross section integrated over the whole angular range and γγ → K 0 K 0 cross section integrated over j cos θj ≤ 0.87, in accordance with the data from Refs. [24,29]. Since the FIG.…”

Section: γγ → Kk Fitsmentioning

confidence: 99%

“…However, while γγ → ππ involves even isospins, the inclusion of the KK channel brings in isospin 1, too. Nevertheless, the older, rather sparse, experimental measurements [24][25][26][27][28][29] of the K þ K − and K 0 K 0 channels limit our amplitudes to a small patch of solutions. When combined with the new high statistics results from Belle [15] on γγ → K s K s , this space narrows to essentially a single solution (we call this solution I).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comprehensive amplitude analysis ofγγ→π+π−,π0π0and
Dai
¹
,
Pennington
²

2014
Phys. Rev. D

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In this paper we perform an amplitude analysis of essentially all published pion and kaon pair production data from two-photon collisions below 1.5 GeV. This includes all the high statistics results from Belle, as well as older data from Mark II at SLAC, CELLO at DESY, and Crystal Ball at SLAC. The purpose of this analysis is to provide as close to a model-independent determination of the γγ to meson pair amplitudes as possible. Having data with limited angular coverage, typically j cos θj < 0.6-0.8, and no polarization information for reactions in which spin is an essential complication, the determination of the underlying amplitudes might appear an intractable problem. However, imposing the basic constraints required by analyticity, unitarity, and crossing symmetry makes up for the experimentally missing information. Above 1.5 GeV multimeson production channels become important, and we have too little information to resolve the amplitudes. Nevertheless, below 1.5 GeV the two-photon production of hadron pairs serves as a paradigm for the application of S-matrix techniques. Final state interactions among the meson pairs are critical to this analysis. To fix these, we include the latest ππ → ππ, KK scattering amplitudes given by dispersive analyses, supplemented in the KK threshold region by the recent precision Dalitz plot analysis from BABAR. With these hadronic amplitudes built into unitarity, we can constrain the overall description of γγ → ππ and KK data sets, both integrated and differential cross sections, including the high statistics charged and neutral pion, as well as K s K s , data from Belle. Since this analysis invokes coupled hadronic channels, having data on both ππ and KK reduces the solution space to essentially a single form in the region where these channels saturate unitarity. For the ππ channel, the separation of isospin-0 and -2 and helicity-0 and -2 components is complete. We present the partial wave amplitudes, show how well they fit all the available data, and give the two-photon couplings of scalar and tensor resonances that appear. These partial waves are important inputs into forthcoming dispersive calculations of hadronic light-by-light scattering. PHYSICAL REVIEW D 90, 036004 (2014) 036004-2 LING-YUN DAI AND M. R. PENNINGTON PHYSICAL REVIEW D 90, 036004 (2014) 036004-4 FIG. 8 (color online). Fit to the γγ → π þ π − differential cross section of CELLO experiment. Here, Cello1 is from Harjes [3] and Cello2 from Behrend et al. [4]. The numbers give the central energy in GeV of each angular distribution listed in order of the cross section at z ¼ 0, where z ¼ cos θ. COMPREHENSIVE AMPLITUDE ANALYSIS OF … PHYSICAL REVIEW D 90, 036004 (2014) 036004-15 FIG. 9 (color online). Fit to the γγ → π þ π − differential cross section of the Belle experiment [13]. The numbers give the central energy in GeV of each angular distribution listed in order of the cross section at z ¼ 0, where z ¼ cos θ. The data are normalized so that the integrated cross section is just a sum of the differential cross sect...

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Measurement ofK + K − production in γγ collisions

Cited by 26 publications

References 24 publications

Hadron pair photoproduction and the Veneziano model

Hadron pair photoproduction and the Veneziano model

Dispersion relation for hadronic light-by-light scattering: two-pion contributions

Comprehensive amplitude analysis ofγγ→π+π−,π0π0and
Dai
¹
,
Pennington
²

2014
Phys. Rev. D

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Measurement ofK + K − production in γγ collisions

Cited by 26 publications

References 24 publications

Hadron pair photoproduction and the Veneziano model

Hadron pair photoproduction and the Veneziano model

Dispersion relation for hadronic light-by-light scattering: two-pion contributions

Comprehensive amplitude analysis ofγγ→π+π−,π0π0andDai1, Pennington2 2014Phys. Rev. D

Contact Info

Product

Resources

About

Comprehensive amplitude analysis ofγγ→π+π−,π0π0and
Dai
¹
,
Pennington
²

2014
Phys. Rev. D