Strong coupling constant from Adler function in lattice QCD

2016 ◽  
Vol 31 (32) ◽  
pp. 1630037
Author(s):  
Renwick J. Hudspith ◽  
Randy Lewis ◽  
Kim Maltman ◽  
Eigo Shintani
Keyword(s):  
Z Boson ◽  
Statistical Error ◽  
Vector Current ◽  
Boson Mass ◽  
Coupling Constant ◽  
Lattice Data ◽  
Momentum Scale ◽  
Local Vector ◽  
Global Fit ◽  
Adler Function

We compute the QCD coupling constant, [Formula: see text], from the Adler function with vector hadronic vacuum polarization (HVP) function. On the lattice, Adler function can be measured by the differential of HVP at two different momentum scales. HVP is measured from the conserved-local vector current correlator using nf = 2 + 1 flavor Domain Wall lattice data with three different lattice cutoffs, up to a[Formula: see text] 3.14 GeV. To avoid the lattice artifact due to O(4) symmetry breaking, we set the cylinder cut on the lattice momentum with reflection projection onto vector current correlator, and it then provides smooth function of momentum scale for extracted HVP. We present a global fit of the lattice data at a justified momentum scale with three lattice cutoffs using continuum perturbation theory at [Formula: see text] to obtain the coupling in the continuum limit at arbitrary scale. We take the running to Z boson mass through the appropriate thresholds, and obtain [Formula: see text](MZ) = 0.1191(24)(37) where the first is statistical error and the second is systematic one.

NUMERICAL ANALYSIS OF GUTs PREDICTIONS IN THE LIGHT OF RECENT RESULTS FROM LEP

1992 ◽  
Vol 07 (35) ◽  
pp. 3319-3330
Author(s):  
DARIUSZ GRECH
Keyword(s):  
Z Boson ◽  
Electromagnetic Coupling ◽  
Boson Mass ◽  
Threshold Effects ◽  
Coupling Constant ◽  
Central Values ◽  
Unified Theories ◽  
Proton Lifetime ◽  
Experimental Values ◽  
Best Fit

We find numerical best fit for sin 2 Θw(MZ), unifying mass MX and the proton lifetime τp as the outcome of analysis where experimental values of Z boson mass MZ, strong coupling constant αs(MZ) and electromagnetic coupling α0(MZ) are taken as the only input parameters. It is found that simple nonsupersymmetric models are unlikely to be realistic ones. On the other hand, we find the best numerical fit: sin 2Θw(MZ = 0.2330 ± 0.0007 (theor.) ± 0.0027 (exp.) , [Formula: see text] yr for supersymmetric unified theories with three generations. The central values require, however, that the supersymmetric mass Λs≲300 GeV . Possibilities of increasing this limit as well as cases with four generations and threshold effects are also discussed. Compact formulas for theoretical and experimental uncertainties involved in the analysis are also produced.

scholarly journals PRECISION MASS DETERMINATION OF THE HIGGS BOSON AT PHOTON–PHOTON COLLIDERS

2000 ◽  
Vol 15 (16) ◽  
pp. 2605-2611 ◽  
Author(s):  
TOMOMI OHGAKI
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Higgs Mass ◽  
Statistical Error ◽  
High Energy ◽  
Boson Mass ◽  
Total Width ◽  
Mass Determination ◽  
The Standard Model

We demonstrate a measurement of the Higgs boson mass by the method of energy scanning at photon–photon colliders, using the high energy edge of the photon spectrum. With an integrated luminosity of 50 fb-1 it is possible to measure the standard model Higgs mass to within 110 MeV in photon–photon collisions for mh=100 GeV. As for the total width of the Higgs boson, the statistical error ΔΓh/Γh SM=0.06 is expected for mh=100 GeV, if both Γ(h→γγ) and [Formula: see text] are fixed at the predicted standard model value.

TESTING SOME PROPERTIES OF NEUTRAL CURRENT NEUTRINO INTERACTIONS IN NEUTRINO COUNTING REACTION

1988 ◽  
Vol 03 (03) ◽  
pp. 721-729 ◽  
Author(s):  
P. RAM BABU
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Z Boson ◽  
Neutral Current ◽  
Z Bosons ◽  
Coupling Constant ◽  
Neutral Currents ◽  
Lorentz Structure ◽  
Neutrino Interactions

We have considered the ‘neutrino counting’ reaction [Formula: see text]. We restrict to V, A Lorentz structure of weak neutral interaction (WNI), allow many Z bosons to mediate WNI and νi to be different from νj. We derive the expression for differential cross section by allowing the polarizations of e+ and e− but summing over the polarizations of final photons. From the study of differential cross section with polarized and unpolarized beams three different coupling constant combinations can be determined. A definite relation between these observables and the observables in [Formula: see text] scatterings is suggested as a test of single-Z-boson hypothesis. Similarly another test relates observables in [Formula: see text] to those of [Formula: see text] scatterings. By assuming universality a test for presence of nondiagonal neutrino neutral currents (NDνNC’s) is also pointed out. The effects of presence of wrong-handed (anti-) neutrinos on our tests are also discussed. As a by-product, we find a way to determine number of neutrino types, in the case i≠j, assuming universality.

CANCELLATION OF ULTRAVIOLET DIVERGENCES IN THE SU(2)L×U(1) ELECTROWEAK MODEL

1989 ◽  
Vol 04 (28) ◽  
pp. 2733-2738 ◽  
Author(s):  
ROGER DECKER ◽  
JEAN PESTIEAU
Keyword(s):  
Top Quark ◽  
Z Boson ◽  
Charged Lepton ◽  
W Boson ◽  
Boson Mass ◽  
Three Generations ◽  
Electroweak Model

We assume that, in the SU(2)L×U(1) model, ultraviolet divergences of the charged lepton self-masses are zero. We predict the top and Higgs masses in the vicinity of the Z-boson mass. Our assumption holds only if there are no more than three generations of quarks and leptons and if quarks and leptons, except for the top quark, have negligible masses compared to the W-boson mass.

scholarly journals Electroweak measurements from W, Z and photon final states

2014 ◽  
Vol 31 ◽  
pp. 1460276
Author(s):  
Hang Yin ◽  
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Z Boson ◽  
W Boson ◽  
Charge Asymmetry ◽  
Distribution Functions ◽  
Boson Mass ◽  
Electroweak Theory ◽  
Final States ◽  
Parton Distribution Functions

We present the most recent precision electroweak measurements of single W and Z boson cross section and properties from the LHC and Tevatron colliders, analyzing data collected by ATLAS, CDF, CMS, D0, and LHCb detectors. The results include the measurement of the single W and Z boson cross section at LHC, the differential cross section measurements, the measurement of W boson mass, the measurement of W and Z charge asymmetry. These measurements provide precision tests on the electroweak theory, high order predictions and the information can be used to constraint parton distribution functions.

scholarly journals Measurement of the Z-boson mass using e+e−→Zγ events at centre-of-mass energies above the Z pole

2004 ◽  
Vol 585 (1-2) ◽  
pp. 42-52 ◽  
Author(s):  
P. Achard ◽  
O. Adriani ◽  
M. Aguilar-Benitez ◽  
J. Alcaraz ◽  
G. Alemanni ◽  
...  
Keyword(s):  
Z Boson ◽  
Boson Mass ◽  
Centre Of Mass

scholarly journals Z-boson hadronic decay width up to $${{\mathcal {O}}}(\alpha _s^4)$$-order QCD corrections using the single-scale approach of the principle of maximum conformality

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Xu-Dong Huang ◽  
Xing-Gang Wu ◽  
Xu-Chang Zheng ◽  
Qing Yu ◽  
Sheng-Quan Wang ◽  
...  
Keyword(s):  
Quantum Chromodynamics ◽  
Perturbative Qcd ◽  
Decay Width ◽  
Z Boson ◽  
Hadronic Decay ◽  
Experimental Measurements ◽  
Renormalization Scale ◽  
Single Scale ◽  
Global Fit ◽  
Principle Of Maximum

AbstractIn the paper, we study the properties of the Z-boson hadronic decay width by using the $$\mathcal {O}(\alpha _s^4)$$ O ( α s 4 ) -order quantum chromodynamics (QCD) corrections with the help of the principle of maximum conformality (PMC). By using the PMC single-scale approach, we obtain an accurate renormalization scale-and-scheme independent perturbative QCD (pQCD) correction for the Z-boson hadronic decay width, which is independent to any choice of renormalization scale. After applying the PMC, a more convergent pQCD series has been obtained; and the contributions from the unknown $$\mathcal {O}(\alpha _s^5)$$ O ( α s 5 ) -order terms are highly suppressed, e.g. conservatively, we have $$\Delta \Gamma _{\mathrm{Z}}^{\mathrm{had}}|^{{{\mathcal {O}}}(\alpha _s^5)}_{\mathrm{PMC}}\simeq \pm 0.004$$ Δ Γ Z had | PMC O ( α s 5 ) ≃ ± 0.004 MeV. In combination with the known electro-weak (EW) corrections, QED corrections, EW–QCD mixed corrections, and QED–QCD mixed corrections, our final prediction of the hadronic Z decay width is $$\Gamma _{\mathrm{Z}}^{\mathrm{had}}=1744.439^{+1.390}_{-1.433}$$ Γ Z had = 1744 . 439 - 1.433 + 1.390 MeV, which agrees with the PDG global fit of experimental measurements, $$1744.4\pm 2.0$$ 1744.4 ± 2.0 MeV.

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