New opportunities in h → 4ℓ
A bstract The Higgs decay h → 4 ℓ has played an important role in discovering the Higgs and measuring its mass thanks to low background and excellent resolution. Current cuts in this channel have been optimized for Higgs discovery via the dominant tree level ZZ contribution arising from electroweak...
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Published in | The journal of high energy physics Vol. 2015; no. 9 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
28.09.2015
Springer Berlin |
Subjects | |
Online Access | Get full text |
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Summary: | A
bstract
The Higgs decay
h
→ 4
ℓ
has played an important role in discovering the Higgs and measuring its mass thanks to low background and excellent resolution. Current cuts in this channel have been optimized for Higgs discovery via the dominant tree level
ZZ
contribution arising from electroweak symmetry breaking. Going forward, one of the primary objectives of this sensitive channel will be to probe other Higgs couplings and search for new physics on top of the tree level
ZZ
‘background’. Thanks to interference between these small couplings and the large tree level contribution to
ZZ
, the
h
→ 4ℓ decay is uniquely capable of probing the magnitude
and
CP phases of the Higgs couplings to
γγ
and
Zγ
as well as, to a lesser extent,
ZZ
couplings arising from higher dimensional operators. With this in mind we examine how much relaxing current cuts can enhance the sensitivity while also accounting for the dominant non-Higgs continuum
q
q
¯
→
4
ℓ
background. We find the largest enhancement in sensitivity for the
hZγ
couplings (≳100%) followed by
hγγ
(≳40%) and less so for the higher dimensional
hZZ
couplings (a few percent). With these enhancements, we show that couplings of order Standard Model values for
hγγ
may optimistically be probed by end of Run-II at the LHC while for
hZγ
perhaps towards the end of a high luminosity LHC. Thus an appropriately optimized
h
→ 4
ℓ
analysis can complement direct decays of the Higgs to on-shell
γγ
and
Zγ
pairs giving a unique opportunity to directly access the CP properties of these couplings. |
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Bibliography: | AC02-07CH11359 USDOE Office of Science (SC), High Energy Physics (HEP) FERMILAB-PUB-15-091-T; LPT-ORSAY-15-22 |
ISSN: | 1029-8479 1029-8479 |
DOI: | 10.1007/JHEP09(2015)185 |