Phenomenology of Vectorlike Confinement Can Kılıç University of Texas at Austin work done with Takemichi Okui arXiv 10014526 JHEP 1004128 2010 Takemichi Okui Raman Sundrum arXiv 09060577 JHEP 1002018 2010 ID: 500319
Download Presentation The PPT/PDF document "The Collider" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
The Collider
Phenomenology of Vectorlike Confinement
Can Kılıç
, University of Texas at Austin
work done with: Takemichi Okui (arXiv: 1001.4526, JHEP 1004:128, 2010 )
Takemichi Okui, Raman Sundrum (arXiv: 0906.0577, JHEP 1002:018, 2010)
Steffen Schumann, Minho Son (arXiv: 0810.5542, JHEP 0904:128, 2009)
Takemichi Okui, Raman Sundrum (arXiv: 0802.2568, JHEP 0807:038, 2008)Slide2
Introduction
The are well into the LHC era.
We
know
that there must be new physics.
Situation very different from previous experiments. No single compelling extension of SM.
Tension for solutions to hierarchy problem from direct searches and precision data.Slide3
What Might Lie Ahead
M
Planck
v
New Physics
The good
(no-tuning):
we just haven’t found the magic theory yet.Slide4
What Might Lie Ahead
M
Planck
v
New Physics
The bad
(severe fine-tuning)
nothing to be seen at LHC except elementary Higgs boson.Slide5
What Might Lie Ahead
The ugly (“meso-tuning”)Look for low-mass tail
M
Planck
v
New Physics
LHC reachSlide6
A Different Angle
Meso-tuning: how to proceed?We take the absence of low energy signatures as a hint
.
A simple module that can fit into of bigger picture.
Theoretically generic
Signatures:
discoverable?
distinguishable?
M
Planck
v
New Physics
LHC reachSlide7
Safe Strong Interactions
LHC Phenomenology of BSM physics dominated by pair production / resonant production: many constraints
Not all possibilities fully explored.
Strong interactions at TeV scale
have been associated with EW-breaking. Signatures very strongly influenced.
Can there be
safe low energy sector
?
Analogy with sub-GeV e+ e- collider. Rich phenomenology from a minimal theory.Slide8
Analogy in a PictureSlide9
Low Energy QCD – A Brief Review
Begin by strongest interactions (
u,d
only)
special because it is light. Guaranteed by breaking of flavor symmetry.
ρ
special because it is the lightest meson that can be resonantly produced once we add electromagnetism. Decays to
.
’s and baryons stableSlide10
Consequences of adding electromagnetism
(
q
u
= 2/3 ,
q
d
= -1/3)
ρ/
γ mixingresonant production
charges mass differenceNeutral can decay
Low Energy QCD – A Brief ReviewSlide11
Both up and down number still conserved, charged
so far stable, turn on weak interactions.Charged
can now decay.
Need light particles for charged
to decay, introduce leptons: non-strongly interacting particles.
as well as neutron decay.
Proton still stable.
Low Energy QCD – A Brief ReviewSlide12
Could Lightning Strike Twice?From a simple UV theory to rich IR Physics
Hypercolor: New fundamental interaction with scale
Λ
HC
.
“Hyper-pions” lightest. Guaranteed by breaking of flavor symmetry.
Hyperpions and baryons stable at this point.
Hyper-
ρ
is the lightest hyper-meson that can be resonantly produced, decays to 2Slide13
Could Lightning Strike Twice?From a simple UV theory to rich IR Physics
Turn on SM interactions (weak+hypercharge
)
hyperfermions
charged under SM.
SM breaks many of the flavor numbers, introduce “species” of
hyperfermions
. (e.g. color triplet)
Each SM gauge boson can mix with a , resonant production. charges (not only electromagnetic)Radiative
masses forAnomaly of neutral pion decay can decay hyper-pion with zero species number ( - short)Species number unbroken. Leads to stable . Slide14
Could Lightning Strike Twice?From a simple UV theory to rich IR Physics
- long stable, SM charged.
Introduce
hyper-weak interactions.
can now decay to a pair of SM fermions (quark or lepton).
Hyper-baryons can be stable or they can decay.Slide15
Recap
For each SM gauge boson, there can be a , with mass ~ Λ
HC
.
masses from
radiative
effects / EWSB /
hyperquark
masses. Produced through SM or through decay. either collider-stable or decay to pairs of SMGBSlide16
Attractive features
PrecedentFlavor blind, therefore safe from low energy searches. You don’t see new physics coming until you produce it directly.
Dilepton
/
dijet
resonance searches evaded.
Rich phenomenology: A minimal theory naturally gives rise to an array of distinct collider signatures (multi-photons, CHAMPs, R-hadrons,
multijets
).
Few free parameters.Slide17
Benchmark I: Without Color
CHAMP and multi-photon production.Spectrum: W’,Z’,B’ at
Λ
HC
. Slide18
Benchmark I : Mass pointsSlide19
Benchmark I: CHAMP signal
Doubly charged scalar decays promptly to CHAMP, decay products unobservableseveral processes add to “CHAMP production”
DistributionsSlide20
CHAMPs: Triggering
Production away from threshold because of spin-1 intermediate state.Acceptance (|
|<2.5) over 90% for all mass points.
Time lag to muon system.Slide21
CHAMPs: BoundsSlide22
CHAMPs: Prospects
Moderate β: TOF, dE/dx, curvature
High-
β
: Analysis by Adams et al. (arXiv: 0909.3157) uses the fact that muons are no longer MIPs at these energies. (200 pb
-1
at 10 TeV)Slide23
CHAMPs: VC Signatures
Can verify spin-1 s-channel productionresonanceSlide24
3γ+W: Final States
Production channels: +-,+0 or -0 (no 00, therefore no 4
γ
)
decays
also 2
γ
from (WZ)(
γγ)(res) / (
γZ)(γW) and (γ
W)(γW)(non-res) – relevant for GMSB searches.Since 3
γ rate comparable, focus on the easier case.Should be easy to distinguish from (fermiophobic) HiggsSlide25
3γ+W: BG
BG: Taking guidance out of h->
γγ
searches, we expect irreducible BG to be O(1) fraction of total BG.
Scale up irreducible BG by x10. (MG
γγ
+jet(s) /
Pythia
/ PGS)
Signal done with batch mode of CalcHep /
Pythia / PGShard pT cut to reduce BGSlide26
3γ+W: BG
BG: Taking guidance out of h->
γγ
searches, we expect irreducible BG to be O(1) fraction of total BG.
Scale up irreducible BG by x10. (MG
γγ
+jet(s) /
Pythia
/ PGS)
Signal done with batch mode of CalcHep /
Pythia / PGShard pT cut to reduce BGSlide27
3γ+W: BG
BG: Taking guidance out of h->
γγ
searches, we expect irreducible BG to be O(1) fraction of total BG.
Scale up irreducible BG by x10. (MG
γγ
+jet(s) /
Pythia
/ PGS)
Signal done with batch mode of CalcHep /
Pythia / PGShard pT cut to reduce BGSlide28
3γ+W:
Use resonance mass from previous part
Define best W candidate
for leptonic W, solve for neutrino rapidity, reconstruct scalar
for hadronic W, take pair (pT>20,
Δ
R<2
) with 70GeV<m
jj<90GeV
Reconstruct ECMConsistency check with CHAMP distributionSlide29
Benchmark II: With Color
R-hadron and multi-jet production
Two resonances, g’ and B’.Slide30
Benchmark II: Mass PointsSlide31
R-hadrons
Large cross section from QCDDistributionsEffect of gg initial state
Hadronization, comparison to CHAMPsSlide32
R-hadrons: Triggering
Very similar kinematics to CHAMPs, good triggering efficiency.Acceptance over 80% for all mass points.Slide33
R-hadrons: VC Signatures
Evidence for g’ resonanceSmaller mass gap4 R-hadron productionSlide34
Multi-jets: Tevatron
Signal dominantly from valence quark initial state, background from gluons. 2
2 vs. 2
many
4j with similar pT. Use pT
1
>120GeV for trigger, 1fb-1 data, 2fb
-1 bgCone jets, ΔR=0.7
For mg’=350GeV use pT4
>40GeV, Δminv
<25GeVFor mg’=600GeV use pT
4>90GeVSlide35
Multi-jets: LHC
For mg’
=750GeV use pT
4
>150GeV,
Δ
m
inv
<50GeV (1fb-1
of data)For mg’=1.5TeV use pT
4>250GeV (10 fb-1 of data)
<2 for all partons,
cone jets, ΔR=0.5
Straightforward to discover scalarSliding cutg’ more tricky.Slide36
Multi-jets at the LHC: BoundsSlide37
Multi-jets: LHC (g’)
Boldly go where no one has gone before: 8 jets.Large cross section for g’ pair production.
Self-calibrating search: m
inv
cuts from 4j, pT cuts from hT.
After pT cuts, signal and bg comparable.Slide38
Multi-jets: LHC (g’) Analysis
parton level truth – PGS level jet matching
Take 4 hardest jets, 4 more out of next 6.
All pairings, use result of 4j analysis
Plot mass of g’ candidates: signal accumulates
Background sanity check: cannot do 2
8 unweighted events, do 26 and shower.
Cross-check with R-hadronsSlide39
Conclusions
VC: QCD-like theories with rich phenomenology, safe from low energy precision tests.
Vector states can be resonantly produced, decay to naturally light scalars.
Scalars have short-lived and collider stable species.
Short-lived scalars decay to a pair of SM gauge bosons.
Long lived scalars appear as CHAMPs / R-hadrons.
Benchmarks
without color: multi-photons, CHAMPs
with color: multi-jets, R-hadrons
Kinematic reconstruction possible in all final states
Novel signatures: Resonances, 4 R-hadronsOther possibilities: decay to fermions, cascades, DM candidatesSlide40
Backup SlidesSlide41
Backup SlidesSlide42
Backup Slides
Anomaly first in shape – then in normalization