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Title: Proceedings, High-Precision $$\alpha_s$$ Measurements from LHC to FCC-ee

This document provides a writeup of all contributions to the workshop on "High precision measurements of $$\alpha_s$$: From LHC to FCC-ee" held at CERN, Oct. 12--13, 2015. The workshop explored in depth the latest developments on the determination of the QCD coupling $$\alpha_s$$ from 15 methods where high precision measurements are (or will be) available. Those include low-energy observables: (i) lattice QCD, (ii) pion decay factor, (iii) quarkonia and (iv) $$\tau$$ decays, (v) soft parton-to-hadron fragmentation functions, as well as high-energy observables: (vi) global fits of parton distribution functions, (vii) hard parton-to-hadron fragmentation functions, (viii) jets in $$e^\pm$$p DIS and $$\gamma$$-p photoproduction, (ix) photon structure function in $$\gamma$$-$$\gamma$$, (x) event shapes and (xi) jet cross sections in $e^+e^-$ collisions, (xii) W boson and (xiii) Z boson decays, and (xiv) jets and (xv) top-quark cross sections in proton-(anti)proton collisions. The current status of the theoretical and experimental uncertainties associated to each extraction method, the improvements expected from LHC data in the coming years, and future perspectives achievable in $e^+e^-$ collisions at the Future Circular Collider (FCC-ee) with $$\cal{O}$$(1--100 ab$$^{-1}$$) integrated luminosities yielding 10$$^{12}$$ Z bosons and jets, and 10$$^{8}$$ W bosons and $$\tau$$ leptons, are thoroughly reviewed. The current uncertainty of the (preliminary) 2015 strong coupling world-average value, $$\alpha_s(m_Z)$$ = 0.1177 $$\pm$$ 0.0013, is about 1\%. Some participants believed this may be reduced by a factor of three in the near future by including novel high-precision observables, although this opinion was not universally shared. At the FCC-ee facility, a factor of ten reduction in the $$\alpha_s$$ uncertainty should be possible, mostly thanks to the huge Z and W data samples available.
Authors:
 [1] ;  [2]
  1. CERN
  2. Monash U.
Publication Date:
OSTI Identifier:
1250540
Report Number(s):
CERN-PH-TH-2015-299; COEPP-MN-15-13; FERMILAB-CONF-15-610-T; arXiv:1512.05194
1409920
DOE Contract Number:
AC02-07CH11359
Resource Type:
Conference
Resource Relation:
Conference: Workshop on high-precision alpha_s measurements: from LHC to FCC-ee, CERN, Geneva, Switzerland, 10/12-10/13/2015
Research Org:
Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS