Presentation on theme: "DIS from EMC to H1 T.Sloan, University of Lancaster. QCDN-06 Rome 2006 EMC proposal ’72-74 Build 1974-1978 Run 1978-1985 NMC (3 rd generation) SMC (4 th."— Presentation transcript:
DIS from EMC to H1 T.Sloan, University of Lancaster. QCDN-06 Rome 2006 EMC proposal ’72-74 Build Run NMC (3 rd generation) SMC (4 th generation) Compass (5 th gen) H1 proposal 1985; Build Run DIS discovered at SLAC in 1960s – 1990 Nobel Prize This led to - later generations of νN and μ(e)N experiments
The Crowning Glory of the Work
EMC Spin Effect.
Proved that only a small fraction of nucleon’s spin is carried by the quarks. Incredible – we all thought we understood the quark-parton model. Is it ΔG or is the nucleon a Skyrmion ? Or is it something else ?
NMC Unexpected Effect (EMC Effect)
H1 How long will F2 Rise ?
EMC BSM Search for free quarks Search for D→μμ Observe J/ψ peak Charm cross section order of magnitude bigger Set limit on BR D→μμ of < (A. Staiano’s thesis ) Sociology – one senior physicist commented on the draft paper Why have you done this analysis ? This is a very quiet paper.
Was he correct ? There are 8 citations for the paper on Spires. Look at quality of the citations 1. Particle data group (paper still there) 2. The experiment which copied us using a pion beam (bigger luminosity) 3. Others If we had found a signal for D→μμ the standard model would have needed modification Conclusion We were right to do the analysis.
The Collaborations EMC and H1 Work divided into several sub groups Structure Functions, Heavy flavour, hadronic final states (EMC and H1) Diffraction, BSM (H1) – diffraction and the standard model not part of vocabulary in EMC days
Heavy Flavour Physics EMC discovered via multimuons that boson gluon fusion was responsible for charm production – among first evidence for gluons
Contribution of b and c to F 2 - F 2 cc and F 2 bb
Hadronic Final States Programme in EMC (NA2, NA9) Lund Model developed for e+e- and μp data (ca1980). Much work was done to tune up the parameters of the model. H1 works in Breit frame, studies jets etc. Jets give insight into production of primary quarks and gluons.
EMC Inclusive Identified Hadrons
EMC Seagull plot – gluon radiation (1983)
H1 Scaling violations in fragmentation functions in Breit Frame compared to e+e- data.
α s versus Q from event shapes
Using dijets to constrain gluon distribution
EW Physics First BCDMS measurement from μ + p μ - p differences BCDMS data
H1 from e + p e - p differences
Are there right handed currents ?
Diffraction Not known in EMC days except for exclusive ρ, φ, J/ψ … Discovered in rapidity gap data at HERA. Now also being studied in forward leading proton and neutron data. Diffraction important for cosmic ray shower generation.
Cosmic Ray shower simulation Energy flow into forward region is very important for simulation of cosmic ray air showers. Estimate ~x% of events have a leading proton and ~y% have a leading neutron. Hence diffraction is important.
ZEUS Leading neutrons Zeus Leading protons
ISR leading photons ISR leading Neutrons (Flauger and Monnig
Leading neutron data – ISR Is the bump at high x one pion exchange ?
Conclusions EMC and H1 have been great places to work. Plenty of outstanding questions – where is the spin of the proton ? What will limit the rise of F 2 ? Is diffraction telling us something about the nuclear force ? Many questions for the workshop
F2 Accuracy Now and 1996 Expected Wider x range expected to be covered (down to compared to ) Improved systematic errors expected in 1996 compared to now. Eg 0.5% electron energy calibration backward and 1% central and forward (compared to 1% backward and 0.7%-3% central-forward). Some work is needed here. –Projected final accuracy is much better at x=0.65 than we actually have now.
PDF Accuracy 1996 Suggested to use jets to determine PDF by G.Lobo – fit made by ZEUS The ZEUS fit already approaches the accuracy expected in 1996.
Measurement of xF3 from e+ e - differences Based on 16 pb -1 of e - data – so improvement expected.
F L Black points from extrapolation Measurement.Open from 4 proton Energies 10pb -1 at each
Diffraction In 1995/6 rapidity gaps had not been known for too long – so plans at workshop were primitive. We have done much more than was considered at the workshop. E.g.F 2 D3,F 2 D4, diffractive charm, vector meson production, dijets, DVCS…
Correlations between quarks studied by DVCS i.e. scatter highly virtual photon and detect a real one (NB e,γ, proton in final state). Several new structure functions are needed to describe such correlations. It is not yet known how to measure them – hence can only compare with models.
Jets and High ET Group I could not find anything on this topic in the workshop that we have not done. Some things extra – odderon searches, anti-deuterons … However, we still have not published the fragmentation functions for identified particles (except π 0 ).
Flagship Plot α S =0.1198±0.0013(exp) (theor)L=106pb -1
EW Plot – Status with 21 pb -1 L and 27 pb -1 R Classic plot demonstrating directly the left handedness of the W – this plot will end up in the text books. Must check with e - which should have negative slope. Poor fit to SM – New physics ? Current limit on Δσ R /σ L is 7% In 1996 projected to achieve 0.4% With L=500pb -1 and 70% polarisation. Use this to set limit on mass of W R
Conclusions Not much in the 1996 workshop to help us today H1 has done great work – I have shown my ideas of the flagship plots which we should leave for future generations. Each sub-group should identify its flagship plots. These should be made before we stop analysing HERA data with the smallest errors possible.