From kotwal@phy.duke.edu Mon Jun 18 17:41:52 2001 Date: Mon, 4 Jun 2001 17:15:28 -0400 (EDT) From: Ashutosh Kotwal Subject: physics topics for VLHC hi, I went through the ATLAS tdr and made a list of topics that could benefit from a VLHC after the LHC. If anyone knows of an SSC physics TDR available online, please let me know because that would be very useful to compare with LHC. QCD processes ------------ 1) Sin2 (theta_W) from forward-backward asymmetry of DY This is also sensitive to new physics through interference with DY. Interference effects can be 'more sensitive' to new physics than production of anomalous events, because interference with SM will show up at first order in new physics coupling, whereas cross section for anomalous events goes as second order in new physics coupling. 2) alpha_s from Z pt and/or Z + jets measurement 3) diffractive physics 4) PDFs - very low x gluons - double parton scattering - saturation of parton densities at very low x Electroweak physics ------------------ 1) W mass - LHC if not Tevatron run 2 will probably do as well as can be done. no obvious gain at VLHC 2) W Width - same as above 3) Trilinear gauge couplings - VLHC can definitely improve on LHC here. B Physics --------- 1) unitarity triangle and CP violation - angle measurements at LHC are statistically limited. VLHC luminosity is similar to LHC, but does increased energy give an advantage? 2) B_s oscillations - is this better at VLHC, because of higher transverse boost? 3) rare B decays - eg. B->mumu is VLHC better than LHC? Heavy quarks and leptons ------------------------ 1) ttbar resonances - VLHC reach should be definitely better than LHC 2) ttbar spin correlations - top quantum numbers 3) top mass - systematics limited - can VLHC exploit a new method to reduce systematics? 4) top couplings 5) charged Higgs in top decays 6) rare top decays 7) single top 8) 4th generation heavy quarks and leptons - LHC reach upto 700 GeV. VLHC can do better. HIGGS ----- LHC will probably see light higgs. VLHC needed for 1) very heavy higgs 2) precise couplings and branching ratios (LHC can measure to 25% accuracy only) 3) higgs spin and parity measurements 4) H->hh in MSSM: couplings between different Higgs is for VLHC to measure 5) precise MSSM higgs couplings and branching ratio measurements 6) composite higgs - spectroscopy of new bound states due to strong dynamics 7) exploiting ttH to measure higgs quantum numbers and other properties. MSSM Higgs ---------- LHC has difficulty at moderate tan(beta) and moderate m_A. SUSY ---- LHC cannot resolve the entire model. We will VLHC for this. Other physics beyond SM ----------------------- Technicolor, compositeness, new gauge bosons, excited quarks and leptons: LHC will not have the last word on this. LHC may just see the low energy end of this spectroscopy. ------------------------------------------------------------------------- Ashutosh V. Kotwal tel: (919) 660-2563 Duke University, Dept. of Physics fax: (919) 660-2525 Box 90305, Durham N.C. 27708-0305, USA kotwal@phy.duke.edu