Physics potential of timing layers in future collider detectors - - PowerPoint PPT Presentation

*Chih-Hsiang Yeh, Sergei Chekanov (Argonne National Lab), Ashutosh Kotwal (Duke University), Shin-Shan Eiko Yu (National Central University)

Physics potential of timing layers in future collider detectors

2020/11/11

Outline

• Motivation
• Publication
• Software and Structure
• Showcases
• Conclusion

Motivation

Motivation

• Future colliders:
• FCC, CEPC, CLIC
• High-precision measurements of particles/jets
• 5D information(position, energy, timing)
• Improve particle/jet reconstruction
• Suppress the background
• CPAD report: Critical needs of Calorimeters (https://arxiv.org/pdf/1908.00194.pdf)
• Pico-second resolution

Add Timing Info

Publications

Publications of our studies

References

• Initial performance studies of a general-purpose detector for multi-TeV

physics at a 100TeV pp collider [JINST/P06009]

• Talking about the structure of our SiFCC detectors and energy resolution
• Studies of granularity of a hadronic calorimeter for tens-of-TeV jets at a 100

TeV pp collider[JINST/P05008]

• Talking about the effect of HCAL granularity

→ →

Publications of our studies

References

• The Latest one!
• Physics potential of timing layers in future collider detectors[JINST/P09021]
• Talking about the timing applied to identify single particle species
• Mainly included in this talk

→ →

Software and Structure

Software and Structure

• Full GEANT4 simulation with SiFCC detectors
• Length between TL1 and TL2: 24cm
• ECAL hits information used to measure the timing difference TL1 and TL2
• 2 x 2(

), 35

• Material: Silicon

𝖽𝗇𝟥 𝖸𝟣

The advantage of TL2

• Identify the stable massive particles [BSM particles] “without knowing a

production vertex”

• Mitigate the situations when the primary vertex position is smeared.
• Correlated with the first layer (TL1), which can provide the directionality of the

particle back-scattered hits can be identified.

→

Showcases

Capability of timing

Peaks are smaller than 1ns Seen as instantaneous hits

→

Resolution: 1ns Resolution: 10ps Distinguish the different particles apart(1GeV) 𝖴𝖴𝖬𝟥 − 𝖴𝖴𝖬𝟤 = 𝖴 (1) (2) Landau peak: 0.7ns Mean: 1.4ns Peak: 0.5ns Peak: 0.5ns Peak: 0.5ns Distinguishable! Non-distinguishable! GEANT4 Simulation! Leading in time hits

Semi-analytic 3- hypothesis

σ

L: Length of particle’s trajectory : Resolution of the detector m: Particle mass p: Momentum of particle : Reference particle mass

σ𝖴𝖯𝖦 𝗇𝖦

If the condition is met, particle can be distinguished from

𝗇 𝗇𝖦

(JHEP 04 (2019) 037 [arXiv:1807.05453)] 


The showcase of 3- hypothesis

σ

K mesons from Pions Heavy particle(BSM) from particle(BKG)

α

Ｗith 1ns resolution, 300MeV-500MeV can be achieved=>Not enough for FCC! Minimum~0.5GeV L= 2m from vertex to ECAL

3GeV

BSM studies General cases

700GeV 70GeV 0.4GeV

Another case

L=0.2m from TL1 to TL2

100GeV 200GeV

Beneficial for particles produced in events with large pile-up (multiple pp interactions)! Also, we don’t need to know about the interaction vertex

0.2m TL1 TL2 Heavy particle(BSM) from particle(BKG)

α

15GeV

Showcase of Dark QCD model

P P

MX MX

SM quark Dark quark SM quark Dark quark Dark Pion Emerging jet

→

Dark Pion Emerging jet

→

Test the capability of using the timing to tag the Dark Pion

JHEP 05 (2015) 059

Setup

CMS s = 𝟤𝟦𝖴𝖿𝖶 SiFCC s = 𝟥𝟪𝖴𝖿𝖶 Production Vertex to ECAL(L) L=1.2m L=2m Dark Pion(m) Momentum of Dark Pion(p) particle ( )

α mF

Momentum of Dark Pion(p)

Track acceptance vs. Calorimeter with the timing

Cover the different ranges! Dark Pion Mass=5GeV, Varying the ctau and Mediator Mass

JHEP 02 (2019) 179

Emerging jets with the same condition as CMS

Dark Pion Mass=5GeV, Varying the ctau and Mediator Mass With the higher resolution With the higher lifetime The acceptance is higher!

Emerging jets for HL-LHC with SiFCC

Mediator Mass=10TeV, Varying the ctau and Dark Pion mass With the higher resolution With the higher lifetime The acceptance is higher!

Conclusion

Conclusion

• Timing layers with tens of picosecond capabilities complement calorimeters with

the standard ~0.5 - 1 ns readout

• Overwhelming benefits for BSM long-lived particles
• Other expected benefits:
• Particle identification (baryons vs pions vs kaons etc.)
• Reducing confusion terms in particle flow algorithm → improvements for jets etc.
• b-tagging, etc.
• To be quantified using realistic Monte Carlo simulations
• Survey for best technology for timing layers is ongoing

Q&A TIME

Thank you for your attention!