|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'504'928
Articles rated: 2609
25 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Muon g-2 estimates : Can one trust Effective Lagrangians and global fits ? | | M. Benayoun
; P. David
; L. DelBuono
; F. Jegerlehner
; | | Date: |
10 Jul 2015 | | Abstract: | Previous studies have shown that the Hidden Local Symmetry (HLS) Model,
supplied with appropriate symmetry breaking mechanisms, provides an Effective
Lagrangian (BHLS) which encompasses a large number of processes within a
unified framework; a global fit procedure allows for a simultaneous description
of the e+ e- annihilation into the 6 final states $pi^+ pi^-$, $pi^0
gamma$, $eta gamma$, $pi^+ pi^- pi^0$, $K^+ K^-$, $K_l K_s$ and includes
the dipion spectrum in the { au} decay and some more light meson decay partial
widths. The contribution to the muon anomalous magnetic moment $a_{th}$ of
these annihilation channels over the range of validity of the HLS model (up to
1.05 GeV) is found much improved compared to its partner derived from
integrating the measured spectra directly. However, most spectra for the
process $e^+ e^- o pi^+ pi^-$ undergo overall scale uncertainties which
dominate the other sources, and one may suspect some bias in the dipion
contribution to $a_{th}$. However, an iterated fit algorithm, shown to lead to
unbiased results by a Monte Carlo study, is defined and applied succesfully to
the $e^+ e^- o pi^+ pi^-$ data samples from CMD2, SND, KLOE (including the
latest sample) and BaBar. The iterated fit solution is shown to be further
improved and leads to a value for $a_{mu}$ different from $a_{exp}$ above the
4 $sigma$ level. The contribution of the $pi^+ pi^-$ intermediate state up
to 1.05 GeV to $a_{th}$ derived from the iterated fit benefits from an
uncertainty about 3 times smaller than the corresponding usual estimate.
Therefore, global fit techniques are shown to work and lead to improved
unbiased results. The main issue raised in this study and the kind of solution
proposed may be of concern for other data driven methods when the data samples
are dominated by global normalization uncertainties. | | Source: | arXiv, 1507.2943 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER