IDEA - Fast and full simulation - agenda.infn.it · M. Antonello, P. Azzi, S. Braibant, E....

M. Antonello, P. Azzi, S. Braibant, E. Fontanesi,

S. Lo Meo, L. Pezzotti, M. Selvaggi

13th June 2019 - Bologna

IDEA Collaboration Meeting

Fast and full simulationof the IDEA detector

Outline2

Geant4

A standalone full simulation

Delphes

A parametricfast simulation

Plan to provide a complete geometry of the IDEA detector in Geant4

Status of the IDEA detector implementation

and possible future improvements

Outline2

Geant4


Delphes


Status of the IDEA detector implementationand possible future improvements

Choice of a standalone Geant4 simulation of the IDEA detector for

performance and local reconstruction studies

to optimize baseline geometry

Outline2

Geant4


Delphes


Status of the IDEA detector implementationand possible future improvements

Plan to provide a standalone Geant4 simulation of the IDEA detector

PHYSICS BENCHMARK STUDIES with the IDEA baseline detector design

PERFORMANCE STUDIES

Delphes fast simulation3

Fast simulation of detector concept

Particle trajectory is followed in the detector.It only needs general volumes foracceptances, a resolution drivensegmentation, resolution and responsefunctions as obtained from full simulation orrelated to desired/studied performances.

A parametric simulation

It takes into account subdetector types(described as cylinders) with their extension,segmentation and resolution:• a tracker in a solenoidal magnetic field,• a calorimeter with its electromagnetic

and hadronic sections,• a muon system. Schematic view of the baseline DELPHES detector

IDEA description in DelphesB field and tracker

4• B field description

(Particle Propagator module)

- Half length of the magnetic field coverage: 2.5 m- Radius of the magnetic field coverage: 2.25 m- Homogeneous magnetic field: 2 T

• Tracker description(TrackingEfficiency, MomentumSmearing module)

The response of tracking detectors has beenparametrized in the same way for electrons,muons and charged hadrons:=> unique efficiency formula (dependent on E and η);=> total pT resolution formula.

|η| ≥ 3.0 0.00%

E ≥ 500 MeV in |η| ≤ 3.0 99.7%

300 ≤ E ≤ 500 MeV in |η| ≤ 3.0 65%

E ≤ 300 MeV in |η| ≤ 3.0 6%

σpT / pT = √[(7.e-5*pT ) 2 + 0.00062]

Idea to include in Delphes the full covariancematrix for tracking parameters smearingprovided by a specific fast simulation [*].

[*] F. Bedeschi @ Oxford: https://indico.cern.ch/event/783429/contributions/3376675/attachments/1829951/2996531/Oxford_April2019_V1.pdf

https://indico.cern.ch/event/783429/contributions/3376675/attachments/1829951/2996531/Oxford_April2019_V1.pdf

➢ Tracking parameter covariance matrix calculationincluding multiple scattering effects

➢ Covariance matrix grid stored for fast calculation Several parametrizations usable in same program

➢ Track parameter smearing according to appropriate covariance matrix Validated with full simulation

Potential implementation in DELPHES➢ Usable to provide to Delphes fast simulation a realistic full covariance matrix to

parametrize track resolution

ROOT based classes:➢ Simple tracking geometry implementation with

txt files: Easy to implement a modified geometry

and change detector performances

Fast tracking simulation5


cos(ϑ)

Mat

eria

l

Thanks to F. Bedeschi


Examplesee ZH (H µµ)ee ZH (Z µµ)• Higgs from Z recoil• Full recoil study (IDEA)

Fast tracking simulation6


L = 5 ab-1

Higgs recoil mass (GeV) Mass (GeV)

Even

ts/1

.0 G

eV

Higgs mass (GeV)

Even

ts/1

.0 G

eV

Even

ts/1

.0 G

eV 0.136% beam spread

0.136% beam spread

Thanks to F. Bedeschi


7• Dual-Readout (DR) calorimeter description

(DualReadout Calorimeter module)

Implementation of a monolithic calorimeter in a dedicated IDEA card:➢ single segmentation

=> Need to define an appropriate granularity➢ different energy resolution for electromagnetic and hadronic showers

E

%1310−

E

%30

IDEA description in DelphesDual-Readout calorimeter

Never implementedand never studiedin a fast simulation

before

IDEA DR calorimeter in Delphes8

E

%1310−

E

%30

e± barrel

Cell size: 6 cm x 6 cm

Validation plots

Energy resolution forreconstructed objects(both had and emparticles) consideringtwo different regionsof pseudorapidity (η)with particle gun eventsγ barrel

endcap

π± barrel

n barrel

endcap

IDEA DR calorimeter in Delphes9

• The geometry is given in Delphes as asegmentation of the calorimeter cylinderin cells (η-φ directions).

• Since each tower reconstructed in thecalorimeter corresponds to a single cell inDelphes work flow, the granularity has tobe defined accordingly to the physicsdimensions of showers.

➢ No clustering➢ No longitudinal segmentation➢ Need to take into account the possible

overlap between particles

Cell size: 30 cm x 30 cm

• Modified Energy Flow in Delphes: hadronic resolution (pessimisticscenario) in case of an electromagneticand hadronic deposit in the same cell

➢ New branch availablein Delphes (by Michele):branch DualReadout

GOAL: Check the effect in Delphes given by changing DR calorimeter granularity

Different cell sizeConfigurations have

been implemented and studied for variousphysics processes

Etower= E1 + E2

E1 E2

Jet energy resolution10

Cell size: 30 cm x 30 cmCell size: 6 cm x 6 cm

Cell size: 6 cm x 6 cm Cell size: 30 cm x 30 cmCell size: 10 mm x 10 mm

ENDCAP

Cell size: 10 mm x 10 mm

BARREL

σ(E

)/E

(%)

σ(E

)/E

(%)

σ(E

)/E

(%)

σ(E

)/E

(%)

σ(E

)/E

(%)

σ(E

)/E

(%)

The jet energy resolution is not particularly affected by the variation of the cell size

Jet angular resolution11

The angular resolution is not so much dependenton the cell size. It decreases in the same way withthe increase of the cell size for PF and Calo jets.

PF jet Calo jet

σ(θ) = θGEN - θRECO

σ(θ) [rad] 2 mm x 2mm 3 cm x 3 cm 30 cm x 30 cm 40 cm x 40 cm 60 cm x 60 cm 80 cm x 80 cm

PF jet 0.01 0.01 0.02 0.02 0.03 0.04

Calo jet 0.03 0.03 0.04 0.05 0.07 0.1

ZH(ττ+jets)12

The number of towers with both an electromagnetic and hadronicdeposit increases when increasing granularity.

Dijet mass resolution is not significantly affected by the different cellsize, while the τ jet invariant mass gets worse.

Need to invastigate this case: τ studies, considering especially π0 decay into two photons

ZH(ττ+jets): ρ invariant mass13

e+ e- Z H

τ+τ-

τ decay forced to ρ π± π0 ντ

Jets (u, d s) Invariant mass of ρ resonance searching for acharged pion and distinguishing two categories:

➢ Presence of two reconstructed pion inthe cone around π±

➢ Presence of one reconstructed pion inthe cone around π±

Cell size: 10 mm x 10 mm Cell size: 6 cm x 6 cmCell size: 30 cm x 30 cmCell size: 40 cm x 40 cmCell size: 60 cm x 60 cmCell size: 80 cm x 80 cm

# reco photons per event

The number of reconstructedphotons per event decreases withthe increasing size of thecalorimeter cells.

➢ If more photons arrive in the samecell, we reconstruct only one ofthem with an energy correspondingto all of them.

14

Considering a cell size of6 cm x 6 cm or greater,the peak in the π± + 2γis considerably reduced.

ZH(ττ+jets): ρ invariant mass

15

The mass resolution on thediphoton invariant massgets worse changing the cellsize from 10 mm x 10 mm to30 cm x 30 cm effectof the implemented EFlow


16

The category π± + 1γshow the effect of theworsen energy resolutionon the photons increasingthe cell size of the DRcalorimeter.


17

Combination of both π± + 2γ and π± + 1γ categories

π± + 2γ π± + 1γ π± + 0γ

2 mm x 2 mm 51% 35% 14%

10 mm x 10 mm 51% 35% 14%

3 cm x 3 cm 51% 35% 14%

6 cm x 6 cm 43% 43% 14%

16 cm x 16 cm 6% 47% 47%

22 cm x 22 cm 2% 32% 66%

30 cm x 30 cm 0.4% 19.3% 80.3%

The best choice seems to be a cell size not greater than 6 cm x 6 cm to be able to reconstructin a good way overlapping photons => we need some investigation using DR full simulation

Selected event for each category (%)


Tracker

(G. Tassielli)

Preshower

(E. Fontanesi)

Magnet

(L. Pezzotti)

Calorimeter

(L. Pezzotti, M. Antonello)

Standalone Geant4 simulation18

Uniqueframework

(S. Lo Meo)

Drift chamber

+

Silicon wrapper

Two μ-RWELL layers in BARREL

+ ENDCAP

MagnetFull projective geometry

(BARREL + ENDCAP)


Uniqueframework

To be tested

[*] See Massimiliano’s talk for details!

[*] More info in my talk later

• A general framework to include standalone geometry of each IDEA sub-detector is ready.This MC provides:➢ the chance to choose a specific physics list (specifying the desired cuts);➢ the possibility to include easily another geometry described in a separate file.cc and file.hh;➢ the creation of a basic rootfile (each sub-detector have to specify its sensitive volume in a

dedicated section).For now it contains only the basic geometry of the preshower detector.

• We imported this new framework in Lorenzo’s github in order to have an easy way toshare the code.


Conclusions and plans20

DELPHES - FAST SIMULATION

The implementation is based on the output of dedicated Geant4 simulation of the IDEAtracker and DR calorimeter

Delphes is flexible enough to provide a fast simulation of the IDEA detector Significant improvements can be provided by the inclusion of the full covariance matrix

to provide tracks smearing, the development of new algorithms oriented to e+e- physics(adeguate clustering for jets), …

GEANT4 – STANDALONE FULL SIMULATION

Combined performances of the IDEA sub-detectors have to be investigated with acomplete full simulation

We are almost ready to try to merge all the IDEA sub-detector in an unique geometry Best solution to have a quick development of the IDEA baseline geometry and then

facilitate the import of the detector description in FCC/CEPC framework

Additional slides

THANK YOU!

IDEA baseline detector

z[m]

r[m]

BARREL until 45° (|η| = 0.88)

ENDCAP

• A magnetic field of 2 T with

- Solenoid length: 5 m- Solenoid inner radius: 2.1 m- Solenoid outer radius: 2.4 m

• A Tracker composed of

- a drift chamber and a drift chamberservice area (DCH);

- silicon pixels and a silicon strips doublestereo layer;

- a μ-RWELL double layer as preshower.Angular coverage up to 100 mrad (η = 3.0)

• A Dual-Readout calorimeterAngular coverage up to 100 mrad (η = 3.0)

• A muon system composed of three

μ-RWELL stations (each of them has abidimensional view)

IDEA tracker – Geant4

• ROOT based classes:➢ Simulation of the tracking system geometry➢ Validation using tracker full simulation in Geant4➢ Easy to implement a modified geometry➢ Easy to change detector performances

Fast tracking simulation


Track fit χ2 linearized in the fit parameters:

Parameter resolution depends only on S and derivatives:

d/d* = predicted/measured distance of track from wire or pixel

p = track parametersS = covariance of all measurements:

resolution & MSMS → worse resolution and non

diagonal correlation terms

cos(ϑ)

Mat

eria

l


Fast tracking simulation



DR full simulation

[*] Massimiliano’s talk here in Bologna

Electron 40 GeV

DR full simulation


Photons 40 GeV

DR full simulation


Pions 40 GeV

ZH(ττ+jets): ρ studiesG

enle

veld

istr

ibu

tio

ns

Gen GenReco

ZH(ττ+jets): ρ studies

π± + 2γ π± + 1γ π± + 0γ # π± matched to τ daughter

2 mm x 2 mm 20309 13757 5508 39574

10 mm x 10 mm 20330 13727 5544 39601

3 cm x 3 cm 20111 13958 5517 39586

6 cm x 6 cm 16889 17131 5575 39595

16 cm x 16 cm 2247 18743 18618 39608

22 cm x 22 cm 616 12745 12745 39594

30 cm x 30 cm 133 7657 31811 39601

40 cm x 40 cm 20 4343 35210 39573

60 cm x 60 cm 5 2547 37017 39569

80 cm x 80 cm 0 1354 38224 39578

Summary of selected event for each category

ZH(eebb)

No significant discrepancies on electron/muon resolution mass:signal leptons are very well isolated,

so changing the granularity does not affect the peak reconstruction

Z mass Higgs recoil mass

Dilepton invariant mass

Comparison with other detectors

Dilepton invariant mass

ZH (10k events)

As we develop the IDEA detector description in Delphes, we try to compare the IDEAperformance with other detector implemented in Delphes and fully validated

➢ waiting for a full simulation of the IDEA detector

Z mass Higgs recoil mass

Dijet invariant mass

ZH(10K events)

As we develop the IDEA detector description in Delphes, we try to compare the IDEAperformance with other detector implemented in Delphes and fully validated

➢ waiting for a full simulation of the IDEA detector

Z(10K events)

Comparison with other detectors

IDEA - Fast and full simulation - agenda.infn.it · M. Antonello, P. Azzi, S. Braibant, E....

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