Photon Structure
This page contains the collection of results on the structure of the photon which have been presented in Phys Rep 332(2000) 165-317. The full paper is available as PDF or PostScript file. A preprint version of this work is available as hep-ex/9912049.
This page provides access to the Encapsulated PostScript files of all Figures. In addition listed are the numerical results presented in the Tables of the appendices C and D. Since the tables are not completely standardised it is advisable to always consult the manuscript before using the numerical results! For convenience, the gzip'ed tar files which always contain the complete most up-to-date Set of Figures and Set of Tables are also available. The results have been collected with great care, however mistakes are not excluded. Please feel free to contact Richard Nisius should you have any comment or question.
Whenever new data on photon structure functions are available or preliminary results are finalised, I intend to update the summary figures. In this case the figure is marked as (updated) and you are directed to a new page giving the record of the changes made. Tables will only be updated should there be an error discovered and corrected.
List of known misprints and acknowledgements
Unfortunately, there are still some misprints in the document.
- Page 182, Equation 27: In the formula for P2max it should read theta2primesquared instead of theta2prime.
- Page 207, item 7 GRsc: The sentence, `The contribution of charm quarks was changed from 1.5 to 1.4 GeV.` , has been truncated and should be replaced by: `The contribution of charm quarks is taken from the leading order Bethe-Heitler formula, both for the leading order and the higher order parametrisations, and the mass of the charm quarks was changed from 1.5 to 1.4 GeV.`
- Page 287, Equation A.16: The Equation should be broken into four lines, i.e. the second line should be split into two before the second occurrence of alpha/2pi.
- Page 303, Table 26: For Q2=59.0 GeV2 the bin boundaries in x should read 0.050 - 0.100 - 0.350 - 0.600 - 0.800. I like to thank Martin Erdmann for spotting this typo.
- Page 310, Ref [49]: The reference should read Nucl Phys B199 instead of PhysLett B199. I like to thank Johannes Hess for spotting this typo.
If you spot something else that is wrong, please let me know.
List of Figures
| Figure | Description |
| Fig01 | Probing the structure of quasi-real photons, g, by highly virtual photons, g*. |
| Fig02 | The different appearances of the photon. |
| Fig03 | A diagram of the reaction ee –> ee ff, proceeding via the exchange of two photons. |
| Fig04 | The different contributions to the reaction ee –> ee g(*)g(*) –> ee ff. |
| Fig05 | Illustrations of the scattering angles barphi, theta* and chi in the photon-photon centre-of-mass system. |
| Fig06 | A schematic view of the OPAL detector. |
| Fig07 | The kinematical coverage of the OPAL detector. |
| Fig08 | The predicted differential cross-section dsigma/dx for the reaction ee –> ee µ+µ- for the acceptance of the PLUTO experiment, and for two different lower limits on W. |
| Fig09 | The predicted differential cross-section dsigma/dx for the reaction ee –> eeµ+µ- for some typical acceptances of a LEP experiment. |
| Fig10 | Comparison of the equivalent photon and the Weizsäcker-Williams approximations. |
| Fig11 | A diagram of the reaction eg –> eg*g –> e ff . |
| Fig12 | The structure functions F2,QED, FA,QED and FB,QED for µµ final states at Q2=1 GeV2. |
| Fig13 | The structure functions F2,QED, FA,QED and FB,QED for µµ final states at Q2=100 GeV2. |
| Fig14 | The P2 dependence of the structure function F2,QED. |
| Fig15 | The QPM prediction for the structure function F2 for light quarks. |
| Fig16 | Comparison of the parametrisations of the x dependence of the leading order asymptotic solution of F2. |
| Fig17 | Comparison of the asymptotic solution and the leading order GRV parametrisation of F2. |
| Fig18 | The structure function F2 in the limit Q2 >> P2 >> Lambda2. |
| Fig19 | The leading order contributions to F2,h. |
| Fig20 | The point-like heavy quark contribution to F2 for various values of Q2. |
| Fig21 | Comparison of parametrisations of the hadron-like contribution to the photon structure function F2. |
| Fig22 | The Q2 dependence of the photon structure function F2 in comparison to the hadron-like contribution. |
| Fig23 | The structure function F2 from the LAC parton distribution functions. |
| Fig24 | The structure function F2 from the WHIT parton distribution functions. |
| Fig25 | Comparison of the GRV leading order and next-to-leading order parametrisations of the photon structure function F2. |
| Fig26 | Comparison of the higher order structure function F2 from AFG and GRV. |
| Fig27 | Comparison of the leading order GRV and GRSc parametrisations of F2. |
| Fig28 | The structure function F2 from the SaS parton distribution functions for several values of Q2. |
| Fig29 | Predictions for the Q2 evolution of the photon structure function F2 for various x ranges. |
| Fig30 | Comparison of leading order parametrisations of the photon structure function F2 for virtual photons. |
| Fig31 | The variation of the P2 suppression of F2 in the SaS1D parametrisations. |
| Fig32 | The predicted P2 suppression of the photon structure function F2(uds). |
| Fig33 | Comparison of the photon structure function F2 for virtual photons with the purely perturbative point-like part. |
| Fig34 | The point-like and hadron-like contributions to F2,c (updated). |
| Fig35 | The measured average structure function <F2,QED> from the CELLO, DELPHI, L3 and the TPC/2g experiments, compared to QED predictions. |
| Fig36 | The world summary of F2,QED measurements (updated). |
| Fig37 | The measured Q2 evolution of F2,QED (updated). |
| Fig38 | The dependence of F2,QED on P2 and on the mass of the muon. |
| Fig39 | The measurements of FA,QED / F2,QED and ½ FB,QED / F2,QED (updated). |
| Fig40 | The measurements of FA,QED and FB,QED. |
| Fig41 | The measurement of the differential QED cross section dsigma/dx for highly virtual photons. |
| Fig42 | The general behaviour of the hadronic energy flow. |
| Fig43 | The correlation between the measured and generated hadronic invariant mass. |
| Fig44 | The measured Et,out distribution for <Q2> = 13 GeV2 in bins of x. |
| Fig45 | The corrected hadronic energy flow for <Q2> = 13 GeV2. |
| Fig46 | The corrected hadronic energy flow for <Q2> = 135 GeV2. |
| Fig47 | Comparison of different methods for the reconstruction of the invariant mass of the hadronic final state. |
| Fig48 | The measured hadronic energy flow from L3. |
| Fig49 | Measurements of the hadronic structure function F2 except from LEP. |
| Fig50 | Comparison of measurements of F2 at low values of Q2. |
| Fig51 | Preliminary update of F2 at low values of Q2 from OPAL. |
| Fig52 | The measurements of F2 at low values of Q2 from L3. |
| Fig53 | The first measurement of F2 for sqrt(see) > mZ . |
| Fig54 | Measurements of the hadronic structure function F2 from LEP (updated). |
| Fig55 | Summary of measurement of the hadronic structure function F2 (updated). |
| Fig56 | The measured Q2 evolution of F2 for three active flavours. |
| Fig57 | The measured Q2 evolution of F2 from OPAL (updated). |
| Fig58 | The measured Q2 evolution of F2 from L3. |
| Fig59 | The measured Q2 evolution of F2 at medium x (updated). |
| Fig60 | Summary of the measurements of the Q2 evolution of F2 (updated). |
| Fig61 | Measurements of the Q2 evolution of F2 compared to a linear fit (updated). |
| Fig62 | The Q2 evolution of F2 for three active flavours compared to the asymptotic solution and the QPM prediction (updated). |
| Fig63 | The effective photon structure function F2,eff from PLUTO. |
| Fig64 | The effective photon structure function F2,eff from L3. |
| Fig65a , Fig65b | The virtuality dependence of F2,eff. |
| Fig66 | The hadronic cross-section for the exchange of two virtual photons from L3. |
| Fig67 | The hadronic cross-section for the exchange of two virtual photons from OPAL. |
| Fig68 | The forward region of a future linear collider detector. |
| Fig69 | The production mechanism for high energetic photons. |
| Fig70 | Prospects for structure function measurements at a future linear collider. |
| Fig71 | Prospects for the measurement of the Q2 evolution of F2 at a future linear collider (updated). |
| Fig72 | Published results on sigmagg as a function of W. |
| Fig73 | Preliminary results on sigmagg as a function of W . |
| Fig74 | Fits to sigmagg using various data and fit assumptions. |
| Fig75 | Transverse momentum distribution dsigma / dpT for hadron production in photon-photon scattering compared to other experiments. |
| Fig76 | Transverse momentum distribution dsigma / dpT for hadron production in photon-photon scattering compared to next-to-leading order calculations. |
| Fig77a , Fig77b | Angular dependence of di-jet production in photon-photon scattering. |
| Fig78 | Transverse energy distribution dsigma / dEjet,T for jet production in photon-photon scattering compared to next-to-leading order calculations. |
| Fig79 | Transverse energy distribution dsigma / dEjet,T for jet production in photon-photon scattering compared to predictions for different parton distribution functions. |
| Fig80 | Differential cross-sections for charm quark production with semileptonic decays into electrons. |
| Fig81 | Differential cross-sections for charm quark production with tagged D* mesons. |
| Fig82 | The separation of the D* production into direct and single-resolved contributions. |
| Fig83 | Total cross-section for charm quark production. |
| Fig84 | Di-jet cross-section in photon-proton scattering compared to next-to-leading order QCD predictions. |
| Fig85 | Inclusive di-jet cross-section for photon-proton scattering from H1. |
| Fig86a , Fig86b | Leading order effective parton distribution function of the photon from H1. |
| Fig87a , Fig87b | Measurements of the gluon distribution function of the photon from H1. |
| Fig88 | Triple differential jet cross-section dsigma/dP2dET2dxg for virtual photons from H1. |
| Fig89 | Leading order effective parton distribution function of virtual photons from H1. |
| Fig90 | The P2 suppression of the leading order effective parton distribution function of virtual photon from H1. |
List of Tables
| Table | Description |
| TabC01 | Results on the average photon structure function <F2,QED> from the CELLO experiment. |
| TabC02 | Results on the average photon structure function <F2,QED> from the DELPHI experiment. |
| TabC03 | Results on the average photon structure function <F2,QED> from the L3 experiment. |
| TabC04 | Results on the photon structure function F2,QED from the OPAL experiment. |
| TabC05 | Results on the photon structure function F2,QED from the OPAL experiment, continued. |
| TabC06 | Results on the photon structure function F2,QED from the PLUTO experiment. |
| TabC07 | Results on the average photon structure function <F2,QED> from the TPC/2g experiment. |
| TabC08 | Preliminary results on the photon structure function F2,QED from the DELPHI experiment. |
| TabC09 | Results on the photon structure functions FA,QED and FB,QED from the L3 experiment. |
| TabC10 | Results on the photon structure functions FA,QED and FB,QED from the OPAL experiment. |
| TabC11 | Preliminary results on the photon structure function ratios FA,QED / F2,QED and ½ FB,QED / F2,QED from the DELPHI experiment. |
| TabC12 | Differential cross-section dsigma/dx for two exchanged virtual photons. |
| TabD01 | Results on the photon structure function F2 from the ALEPH experiment. |
| TabD02 | Results on the photon structure function F2 from the AMY experiment. |
| TabD03 | Results on the photon structure function F2 from the DELPHI experiment. |
| TabD04 | Results on the photon structure function F2 from the JADE experiment. |
| TabD05 | Rsults on the photon structure function F2 from the L3 experiment. |
| TabD06 | Results on the photon structure function F2 from the OPAL experiment (updated). |
| TabD07 | Results on the photon structure function F2 from the PLUTO experiment. |
| TabD08 | Results on the photon structure function F2 from the TASSO experiment. |
| TabD09 | Results on the photon structure function F2 from the TPC/2g experiment. |
| TabD10 | Results on the photon structure function F2 from the TOPAZ experiment. |
| TabD11 | Additional preliminary results on the photon structure function F2 from the ALEPH experiment. |
| TabD12 | Additional preliminary results on the photon structure function F2 from the DELPHI experiment. |
| TabD13 | Additional preliminary results on the photon structure function F2 from the L3 experiment. |
| TabD14 | Results on the Q2 evolution of F2 for three active flavours. |
| TabD15 | Results on the Q2 evolution of F2 for four active flavours. |
| TabD16 | Preliminary results on the Q2 evolution of F2. |