ABCDEFGHIJKLMNOPQRSTUVWXYZ
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changes after Venice marked in pink
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Notation:
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a = \alpha_ew
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as = \alpha_s
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at = y_t^2/(4 pi)
(ew. corr. enhanced by top mass)
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af = \alpha_ew with closed fermion loop
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Higgs decays(slide 5)
red = updated compared to Snowmass 21/22
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currentfuture projection (conservative)future projection (agressive)
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th.err. estimateavail. ordersth.err. estimateadditional orders availablecommentsth.err. estimateadditional orders availablecomments
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bb/cc [%]<0.4as^4+a+at^2+at*as0.2a^2+a*as0.1as^5unc. dominated by N3LO mixed EW-QCD
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ττ/μμ [%]<0.3a+at^2+at*as<0.1a^2+a*as0.05 ??a*af^2+a*af*aswhat is dominant remaining error? how to estimate?
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WW/ZZ [%]0.5as+a+at^2+at*as0.3as^2
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gg [%]3.2as^3+a1.0as^40.5as^5+a*asunc. dominated by a^2 (3-loop)
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γγ [%]<1.0as^2+a0.4a*asunc. dominated by a^2 (3-loop)
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Zγ [%]1.5as+a
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Higgs production(slide 8+9)
red = updated compared to Snowmass 21/22
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currentfuture projection (conservative)future projection (agressive)
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th.err. estimateavail. ordersth.err. estimateadditional orders availablecommentsth.err. estimateadditional orders availablecomments
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HZ [%]0.3a+a*as+af*a<0.1a^2estimate based on prefactors (see below)
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WW fusion [%]~1a~0.1a*as+a^2simply using the HZ estimates
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Prefactor estimates: [del(x) = relative cross-section correction of O(x)]
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del(a^3) = del(a^2) * a/pi*nf, where a = g^2/(4*pi), nf = 12 = # of charged fermion species
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del(a^2*as) = del(a^2) * as/pi*2*CF (heuristic factor 2 to account for diagram combinatorics)
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del(a*as^2) = del(a*as) * as/pi*2*CA (heuristic factor 2 to account for diagram combinatorics)
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Z-pole "backgr."(slide 12)
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currentfut. projectionComments:
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sig^0_had5 pb0.8 pbMethod used by AF:
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R^0_l2.1e-30.27e-3
(a) evaluate predictions using GRIFFIN with and without NLO corrections for contributions beyond leading Z pole.
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R^0_c2.3e-60.34e-6
(b) multipy this difference by factor a/pi*nf to get current uncertainty, where a = g^2/(4*pi), nf = 12 = # of charged fermion species
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R^0_b1.5e-60.23e-6
(c) multiply once more by a/pi*nf to get future uncertainty
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Gamma_Z0.11 MeV0.016 MeV
(d) for a*as (current) use known af*as corrections as proxy
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sineff_l (from AFB_l)20e-42.4e-4
(e) for a^2*as (future) multiply (a) by relative factor af*as/a; for a*as^2 (future) multiply af*as by factor as/pi*2*CA
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sineff_l(from AFB_b)1.2e-40.15e-4
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AFB_l3.4e-44.2e-5
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AFB_b1.1e-42.2e-5
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AFB_c0.8e-41.6e-5
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ALR(from ee->had)1.4e-42.9e-5
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P_tau3.0e-44.0e-5
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QED MC errors(slide 14)
estimates from 1903.09895
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currentfut. projectionneeded improvements
Comments/questions:
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sig^0_had25 pb1.5 pb
fermion pairs, IFI beyond O(a)
(a) QED uncertainties for R^0_{b,c} should be smaller than for R^0_l, but by how much?
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R^0_l12e-30.3e-3
fermion pairs, FSR, IFI beyond O(a)
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m_Z0.3 MeV0.03 MeVfermion pairs
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Gamma_Z0.2 MeV0.03 MeVfermion pairs
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sineff_l (from AFB_l)2.8e-40.05e-4 ??
full O(a^2) QED plus log-enhanced O(a^3)
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AFB_l5e-40.09e-4see above
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m_W(from thrs. scan)3 MeV0.3 MeVO(a^2) QED corrections for W prod. and decay; soft photon exponen. for photons emitted from W bosons; improved ISR
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QCD MC errors(slide 15+16)
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currentfut. projection (conservative)commentsfut. projection (agressive)comments
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R_b(rel. uncertainty)2.00E-032.00E-04dominated by gluon splitting; based on hep-ex/0509008, 2209.08078; assume factor 10 improvement compared to LEP4.00E-05assume factor 50 improvement compared to LEP
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R_b(abs. uncertainty)4.40E-044.40E-058.80E-06
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R_c(rel. uncertainty)1.00E-021.00E-032.00E-04
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R_c(abs. uncertainty)1.70E-031.70E-043.40E-05
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A_b / A_c(rel. uncertainty)1.04E-032.24E-04based on 2010.08604, 2209.08078; assume 0.3 acol. cut, NNLO QCD, factor 5 improvement in non-perturb. QCD2.83E-05assume N3LO QCD (factor as/pi*2*CA ~ 5 improvement) and factor 50 improvement in np. QCD
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A_b(abs. uncertainty)9.61E-042.06E-042.60E-05
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A_c(abs. uncertainty)7.00E-041.50E-041.90E-05
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Z-pole SM predict.(slide 3)
red = updated compared to Snowmass 21/22
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currentfuture projection (conservative)fut. projection (agressive)
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Gamma_Z [MeV]0.40.080.016
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R_l6e-31.2e-32e-4
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R_b1e-42e-53.5e-6
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R_c5e-51.0e-52e-6
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sig^0_had [pb]61.60.3
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sin^2\theta_eff^l4.5e-50.7e-50.06e-5
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M_W [MeV]410.1
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Assumptions:
currently avail. orders: a^2 + a*as + at*as^2 + at^2*as + at^3 + at*as^3
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conservative additional orders: a*as^2 + a^2*as + af^2*a + at^2*as + at^3*as + at^4 +as^5
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aggressive additional orders: a^3 + a^2*as^2 + af^2*a*as + af^2*a^2 + at*as^4 + at^2*as^3 + as^6
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Method:
extrapolation of known order ratios (e.g. [a^2*as] = [a^2] / [a] * [a*as] )
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SM parameters(slide 22 ff)
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No updates performed here!
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currentfuture projection (conservative)fut. projection (agressive)Comments
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m_t50 MeV30 MeV
based on 1711.10429, 1906.05379
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alpha_s1e-33e-41e-4
comfirm against QCD group
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\Delta\alpha<1e-4<5e-51...3e-5
conservative from Jegerlehner using e+e- data and Adler method; aggressive from direct measurement based on Janot's or Riembau's methods
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m_W (from thrsh.)3 MeV0.6 MeV