tesis - bib-pubdb1.desy.debib-pubdb1.desy.de/record/209420/files/presentation_0.pdf · title: tesis...
TRANSCRIPT
Mikael Chala (DESY)in collaboration with F. del Águila, A. Santamaria
and J. Wudka. Based on 1311.1510 and 1305.3904.
BLV2015, UmassAmherst, April 29, 2015
Colliders Signatures ofLNV Higgs Sectors
The Standard Model is very strong
TeV scale
valid u
p t
o
Renormalizable
Stable vacuumDegrassi et al., 1205.6497
...
Planck scale
ModelBLV2015, UmassAmherst, April 29, 2015
Majorana neutrinos...About Lepton Number Violation
Accidental symmetry broken byneutrino Majorana mass terms
decay
BLV2015, UmassAmherst, April 29, 2015
The natural scale of LNV scalars
TeV scale
valid u
p t
o
Planck scale
Natural assumption
BLV2015, UmassAmherst, April 29, 2015
The natural scale of LNV scalars
TeV scale
valid u
p t
o
Planck scale
Naturalassumption
del Águila et al,1204.5986, 1111.6960
Gustafsson et al,1212.4806
BLV2015, UmassAmherst, April 29, 2015
Outline
Distinguishing LNV scalars at the LHC RUN2
Observing LNV scalar interactions at the LHC?
A generic approach to LNV scalars
BLV2015, UmassAmherst, April 29, 2015
LNV extensions of the SM canaccommodate neutrino Majoranamasses
Only three scalar fields at therenormalizable level
BLV2015, UmassAmherst, April 29, 2015
Experiment scale
Different doubly-charged scalar
at a lower scale can mix with
LNV extensions of the SM canaccommodate neutrino Majoranamasses
Only three scalar fields at therenormalizable level
BLV2015, UmassAmherst, April 29, 2015
After integrating out scale, higher multiplets ( )
couple to same-sign leptons via Yukawa-like interactions
BLV2015, UmassAmherst, April 29, 2015
Either or
What about
Equivalent by the ec. motion and integration + others?
After integrating out scale, higher multiplets ( )
couple to same-sign leptons via Yukawa-like interactions
and suppressed by powers of
BLV2015, UmassAmherst, April 29, 2015
What is the phenomenology of these scalars?
VS
What current analyses assume (see-saw II)?
ATLASEur.Phys.JC72-2244
CMSEur.Phys.JC72-2189
BLV2015, UmassAmherst, April 29, 2015
Observing LNV interactions in simplest
models can be really hard
BLV2015, UmassAmherst, April 29, 2015
Using current CMS three- and four-lepton analyses, set
bounds on LNV processes mediated by doubly-charged scalars
BLV2015, UmassAmherst, April 29, 2015
Using current CMS three- and four-lepton analyses, set
bounds on LNV processes mediated by doubly-charged scalars
BLV2015, UmassAmherst, April 29, 2015
Using current CMS three- and four-lepton analyses, set
bounds on LNV processes mediated by doubly-charged scalars
BLV2015, UmassAmherst, April 29, 2015
F. del Águila and M.C., 1311.1510
Efficien
cies in
%
Can we discriminate among the different multiplets?
LNV can be very difficult to be established at the LHCBut doubly-charged scalars can be still present
Discrimination is possible if two-body decays dominate
Measure the neutral
cross section using
four-lepton events
arXiv:1305.3904
BLV2015, UmassAmherst, April 29, 2015
BLV2015, UmassAmherst, April 29, 2015
BLV2015, UmassAmherst, April 29, 2015
Distinguishing the
different
four-lepton channels
BLV2015, UmassAmherst, April 29, 2015
Distinguishing the
different
four-lepton channels
BLV2015, UmassAmherst, April 29, 2015
Distinguishing the
different
four-lepton channels
BLV2015, UmassAmherst, April 29, 2015
Distinguishing the
different
four-lepton channels
BLV2015, UmassAmherst, April 29, 2015
How well can we discriminate among the different multiplets?
14 TeV, L = 100, 300, 3000/fb - Only light leptons
- Light leptons and taus
- Light leptons and Ws
- Light leptons taus and Ws
Águila, MC, Santamaría, Wudka, '13
BLV2015, UmassAmherst, April 29, 2015
Doublet caseSinglet case
BLV2015, UmassAmherst, April 29, 2015
It is a background of
Charged signals VS neutral current backgrounds
Cut here mainly signal
BLV2015, UmassAmherst, April 29, 2015
Conclusions
BLV2015, UmassAmherst, April 29, 2015
The SM describes nature to a very good accuracy, although there are still open questions: neutrino masses
LNV scalar interactions can be very difficult to be proved at the LHC
For the first time, bounds on LNV scalar interactions, and many other channels
Thank you!Even if no LNV, doubly-charged scalars can be distinguished in a large run of LHC
BLV2015, UmassAmherst, April 29, 2015