There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

http://risa.stanford.edu/teaching/362/particledarkmatter.pdf

Particle dark matter: Evidence, candidates and constraints

This paper gives the 2010 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. The 2010 adjustment takes into account the data considered in the 2006 adjustment as well as the data that became available from 1 January 2007, after the closing date of that adjustment, until 31 December 2010, the closing date of the new adjustment. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2010 set replaces the previously recommended 2006 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.

/pdf/codata-recommended-values-of-the-fundamental-physical-4bsdant71c.pdf

CODATA Recommended Values of the Fundamental Physical Constants: 2006

Theory and phenomenology of two-Higgs-doublet models

Combining our results for various $O({\ensuremath{\alpha}}_{s}^{2})$ corrections to the weak radiative $B$-meson decay, we are able to present the first estimate of the branching ratio at the next-to-next-to-leading order in QCD. We find $\mathcal{B}(\overline{B}\ensuremath{\rightarrow}{X}_{s}\ensuremath{\gamma})=(3.15\ifmmode\pm\else\textpm\fi{}0.23)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ for ${E}_{\ensuremath{\gamma}}g1.6\text{ }\text{ }\mathrm{GeV}$ in the $\overline{B}$-meson rest frame. The four types of uncertainties: nonperturbative (5%), parametric (3%), higher-order (3%), and ${m}_{c}$-interpolation ambiguity (3%) have been added in quadrature to obtain the total error.

/pdf/estimate-of-b-b-x-s-g-at-o-a-s-2-4jg4ehoar4.pdf

Estimate of B(B̄→X s γ) at O(α s 2 )

Effects of strong interactions on the two loop electroweak radiative corrections to the muon anomalous magnetic moment, $a_\mu=(g_\mu-2)/2$, are examined. Short-distance logs are shown to be unaffected. Computation of long-distance contributions is improved by use of an effective field theory approach that preserves the chiral properties of QCD and accounts for constraints from the operator product expansion. Small, previously neglected, two loop contributions, suppressed by a $1-4\sin^2\theta_W$ factor, are computed and the complete three loop leading short-distance logs are reevaluated. These refinements lead to a reduction in uncertainties and a slight shift in the total electroweak contribution to $a_\mu^{\rm EW} = 154(1)(2)\times 10^{-11}$ where the first error corresponds to hadronic uncertainties and the second is primarily due to the allowed Higgs mass range.

Refinements in electroweak contributions to the muon anomalous magnetic moment

Standard model loop contributions to the muon anomalous magnetic moment, a{sub {mu}}equivalent to(g{sub {mu}}-2)/2, and their theoretical uncertainties are scrutinized. The status and implications of the recently reported 2.6 sigma experiment versus theory deviation a{sub {mu}}{sup expt}-a{sub {mu}}{sup SM}=426(165) x 10{sup -11} are discussed. Possible explanations due to supersymmetric loop effects with m{sub SUSY}{approx_equal}55{sub -8}{sup +16}tan {beta} GeV, radiative mass mechanisms at the 1--2 TeV scale and other ''new physics'' scenarios are examined.

Muon anomalous magnetic moment: A harbinger for ''new physics''

/pdf/estimate-ofb-b-xsg-ato-as2-7s4458i80k.pdf

Estimate ofB(B¯→Xsγ)atO(αs2)

Decay rates of unpolarized top quarks into longitudinally and transversally polarized W bosons are calculated to second order in the strong coupling constant {alpha}{sub s}. Including the finite bottom quark mass and electroweak effects, the standard model predictions for the W-boson helicity fractions are F{sub L}=0.687(5), F{sub +}=0.0017(1), and F{sub -}=0.311(5).

/pdf/helicity-fractions-of-w-bosons-from-top-quark-decays-at-next-oywngcgdl6.pdf

Andrzej Czarnecki

Papers

Estimate of B(B̄→X s γ) at O(α s 2 )

Refinements in electroweak contributions to the muon anomalous magnetic moment

Muon anomalous magnetic moment: A harbinger for ''new physics''

Estimate ofB(B¯→Xsγ)atO(αs2)

Helicity fractions of W bosons from top quark decays at next-to-next-to-leading order in QCD