SEARCH FOR HIGHLY IONIZING PARTICLES WITH THE PIXEL DETECTOR AT - - PowerPoint PPT Presentation

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SEARCH FOR HIGHLY IONIZING PARTICLES WITH THE PIXEL DETECTOR AT - - PowerPoint PPT Presentation

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1 SEARCH FOR HIGHLY IONIZING PARTICLES WITH THE PIXEL DETECTOR AT BELLE II Katharina Dort, Soeren Lange, Klemens Lautenbach (katharina.dort@physik.uni-giessen.de) International Workshop on e+e- collisions from Phi to Psi 28/02/2019 WHAT

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SLIDE 1

SEARCH FOR HIGHLY IONIZING PARTICLES WITH THE PIXEL DETECTOR AT BELLE II

1

Katharina Dort, Soeren Lange, Klemens Lautenbach

(katharina.dort@physik.uni-giessen.de)

International Workshop on e+e- collisions from Phi to Psi 28/02/2019

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SLIDE 2

WHAT ARE HIGHLY IONIZING PARTICLES?

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

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SLIDE 3

HIGHLY IONIZING PARTICLES

  • Examples:
  • Anti-Deuterons
  • Magnetic Monopoles

3

eg = nℏc 2 ≈ 68.5e ⋅ n

= particles with a characteristically high energy loss

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • Monopoles appear in various theories

('t Hooft, GUT, String Theories etc.)

  • Monopoles arising from Dirac Quantization

Theory:

Paul A. Dirac, Proc. R. Soc. Lond. A, 133, 60-72 (1931)
  • G. Lazarides et al., Phys. Rev. Lett., 49, 1756 (1982)
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SLIDE 4

CHARACTERISTICS OF MAGNETIC MONOPOLES

4

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

Non-Bethe-Bloch energy loss Trajectory in magnetic field

➡ See Dark Sector physics at Belle II at

XXXIX International Conference on High Energy Physics by Dmitrii Neverov

Beryllium

dE/dxmpl ≈ β2 ⋅ dE/dxBethe−Bloch

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SLIDE 5

WHAT SEARCH STRATEGY IS PURSUED?

5

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

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SLIDE 6
  • Searches at electron-positron colliders:
  • MODAL at LEP : NTDs
  • TRISTAN at KEK : NTDs
  • CLEO at CESR : NTDs
  • PETRA at DESY : NTDs
  • TASSO at DESY : Tracking
  • OPAL at LEP : Wire Chamber

PAST SEARCHES

6

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • W. Braunschweig et al. [TASSO Collaboration], Z. Phys. C 38, 543 (1988)
  • Most searches

performed with Nuclear Track Detectors (NTDs)

The MoEDAL Experiment
  • T. Gentile et al. [CLEO Collaboration], Phys. Rev. D 35, 1081 (1987).
  • W. Braunschweig et al. [TASSO Collaboration], Z. Phys. C 38, 543 (1988)
  • P. Musset, M. Price and E. Lohrmann, Phys. Lett. 128B, 333 (1983)
  • K. Kinoshita et al., Phys. Lett. B 228, 543 (1989)
  • J. L. Pinfold, et al. Phys. Lett. B 316, 407 (1993)
  • G. Abbiendi et al. [OPAL Collaboration], Phys. Lett. B 663, 37 (2008)
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SLIDE 7

SUPER KEKB

7

  • Asymmetrical Electron-

Positron Collider with center-

  • f-mass energy of 10.58 GeV

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

40x KEKB peak luminosity:

ℒ = 8 ⋅ 1035cm−2s−1

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SLIDE 8

BELLE II DETECTOR

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

More details:

Super KEKB and Belle2 status and plans

from Prof. Xiaolong Wang Vertex Detector Central Drift Chamber Electromagnetic Calorimeter KLong/Muon Detector Aerogel RICH Time-of-Propagation Counter

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SLIDE 9

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

9

Plan for post-LHC physics?

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PIXEL DETECTOR

2 layer DEPFET Pixel Detector (PXD)

  • R = 1.4 cm / 2.2 cm
  • Thickness: 75 μm
  • Pixel size: 50 μm - 85 μm
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SLIDE 10

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

10

Plan for post-LHC physics?

10

PIXEL DETECTOR

2 layer DEPFET Pixel Detector (PXD)

  • R = 1.4 cm / 2.2 cm
  • Thickness: 75 μm
  • Pixel size: 50 μm - 85 μm

H i g h s p a t i a l r e s

  • l

u t i

  • n

i n c l

  • s

e p r

  • x

i m i t y t

  • t

h e i n t e r a c t i

  • n

r e g i

  • n
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SLIDE 11
  • Searches at electron-positron colliders:
  • MODAL at LEP : NTDs
  • TRISTAN at KEK : NTDs
  • CLEO at CESR : NTDs
  • PETRA at DESY : NTDs
  • TASSO at DESY : Tracking
  • OPAL at LEP : Wire Chamber

PAST SEARCHES

11

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • W. Braunschweig et al. [TASSO Collaboration], Z. Phys. C 38, 543 (1988)
  • Most searches

performed with Nuclear Track Detectors (NTDs)

The MoEDAL Experiment
  • T. Gentile et al. [CLEO Collaboration], Phys. Rev. D 35, 1081 (1987).
  • W. Braunschweig et al. [TASSO Collaboration], Z. Phys. C 38, 543 (1988)
  • P. Musset, M. Price and E. Lohrmann, Phys. Lett. 128B, 333 (1983)
  • K. Kinoshita et al., Phys. Lett. B 228, 543 (1989)
  • J. L. Pinfold, et al. Phys. Lett. B 316, 407 (1993)
  • G. Abbiendi et al. [OPAL Collaboration], Phys. Lett. B 663, 37 (2008)

Belle II at KEK : PXD (+ Tracking)

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SLIDE 12

PIXEL DETECTOR (PXD)

12

  • Principal purpose of PXD: Tracking in

close proximity to interaction region

  • Our objective: Check if particle

identification with PXD is feasible

Input Variables

Cluster size properties + Charge distribution in cluster ——————————————————————— 6-dim input vector

  • r

5x5 pixel matrix around cluster

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

Neural Networks

Feed-Forward Networks Unsupervised Training: Self - Organizing Maps

  • Dirac monopoles do not reach outer

sub-detectors

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SLIDE 13

PIXEL DETECTOR (PXD)

13

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • Principal purpose of PXD: Tracking in

close proximity to interaction region

  • Our objective: Check if particle

identification with PXD is feasible

  • Dirac monopoles do not reach outer

sub-detectors

Input Variables

Cluster size properties + Charge distribution in cluster ——————————————————————— 6-dim input vector

  • r

5x5 pixel matrix around cluster Neural Networks

Feed-Forward Networks Unsupervised Training: Self - Organizing Maps

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SLIDE 14

WHAT’S THE STATUS?

14

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

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SLIDE 15

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

Minimum ionizing particles

STATUS - MONOPOLE SIMULATION

Testbeam at DESY and CERN

DEPFET Technology, Test Beam Performance at Taller de Altas Energías 2013 by Boronat et al.

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SLIDE 16

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • Preliminary simulation of 1 GeV magnetic monopoles with unit charge:

Preliminary Preliminary

STATUS - MONOPOLE SIMULATION

Belle II Simulation Belle II Simulation

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SLIDE 17

17

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • Preliminary simulation of 1 GeV magnetic monopoles with unit charge:

Preliminary

STATUS - MONOPOLE SIMULATION

Belle II Simulation

Preliminary

Background

Belle II Simulation

Monopoles

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SLIDE 18

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

STATUS - IDENTIFICATION OF ANTI-DEUTERONS

Belle II Simulation Belle II Simulation

  • Branching fraction in decay:

Υ(4S) Γi/Γ < 1.3 ⋅ 10−5

Preliminary Preliminary

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SLIDE 19

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

STATUS - CLASSIFICATION WITH NEURAL NETWORK

  • Motivation: Online

identification with PXD to prevent loss of HIP events

  • Challenge: Background at

least four orders of magnitude higher

Preliminary Preliminary

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SLIDE 20

OUTLOOK AND CONCLUSION

20

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • Challenge: Identification of HIPs complicated due to short

range in detector

  • Strategy: HIP identification with the Belle II Pixel Detector
  • Status: Feasibility study underway / implementation of

monopole simulation currently evaluated

  • Future Objective : HIP identification on hardware level
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SLIDE 21
  • Challenge: Identification of HIPs complicated due to short

range in detector

  • Strategy: HIP identification with the Belle II Pixel Detector
  • Status: Feasibility study underway / implementation of

monopole simulation currently evaluated

  • Future Objective : HIP identification on hardware level

OUTLOOK AND CONCLUSION

21

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

Спасибо за внимание!

Thank you for your attention!

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SLIDE 22

BACK-UP

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

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SLIDE 23

SUPER-KEKB

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

Phase II: ~

0.5 fb−1

First collision: April 2018

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SLIDE 24

MONOPOLE PRODUCTION

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PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • Monopole pair production:

e+e− → γ* → M+M−

  • No perturbative treatment possible due

to large coupling constant

  • Based on QED pair production:

αm ≈ 34n2

σ(e+e− → M+M−)/σ(e+e− → μ+μ−) ∝ β3( ng e )2

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SLIDE 25

WHY NOT DETECTED YET?

25

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • General-purpose detectors in

today’s particle physics experiments not suitable for HIPs Characterize detector with HIP source (e.g. alpha emitter)

  • Short range prevents activation of

trigger

  • Conventional tracking algorithms

do not recognize trajectory Provide (partial) particle identification with inner detectors Implement Monopole-tracking

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SLIDE 26

MAGNETIC MONOPOLES

  • Modified Maxwell equations:

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∇D = 4πρe ∇B = 4πρm −∇ × E = 1 c ∂ ∂t B + 4π c jm ∇ × H = 1 c ∂ ∂t D + 4π c je .

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

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SLIDE 27

27

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

  • Preliminary simulation of 1 GeV magnetic monopoles with unit charge:

Preliminary Preliminary

STATUS - MONOPOLE SIMULATION

Belle II Simulation Belle II Simulation

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SLIDE 28

NEURAL NETWORKS

28

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN

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SLIDE 29

SELF-ORGANIZING MAPS

29 Self organizing maps

  • Node space: 15 x 15
  • Size of input vector: 6
  • 40,000 input vectors (50% anti-

deuterons, 50% background)

  • Gaussian learning function
  • 400,000 iterations (1 vector per

iteration)

  • Test with 3,000 vectors
  • Deuterons
  • Background

PHIPSI19 NOVOSIBIRSK KATHARINA DORT, UNIV. OF GIESSEN