Sunny Seo, IBS IBS-KMI Workshop 2020.08.24 - PowerPoint Presentation

Slide1

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

1

Dark Photon

Sensitivityat Yemilab

Sunny Seo @ IBS-CUP

2020.08.24

IBS-KMI

Joint Workshop

Slide2

Standard Model has been very successful

But

…

e

+ excess in cosmic rays(PAMELA, FERMI, AMS)Excess of events of unknown origin(DAMA/LIBRA, CoGENT

)Anomalous magnetic moment of muon: am = (gm-2)/2

Dark

sector ?

p excess

in cosmic rays

(AMS)

proton

radius:

7

s

discrepancy

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

2

Slide3

Visible Universe

(Standard model particles)

Dark Universe

(Dark matter etc.)Portal

3

Slide4

Portals (mediators) to Dark Sector

L

=

L

SM + LMediator + LDSVisible sector

Dark sector

Portals to

dark sector

Standard Model symmetries allow

only a few important interactions.

“Neutrino”, “Higgs”, “

Axion

”, and “Vector” portals

Sunny Seo, IBS

4

IBS-KMI Workshop 2020.08.24

Slide5

Visible sector

Dark sector

Portals to

dark sector

d

ark Higgs

Higgs

v

ector

d

ark photon

neutrino

s

terile neutrino

axion

ALPs

L

mediator

Sunny Seo, IBS

5

Slide6

“

Kinetic Mixing

”

Photon (

g) and Dark Photon (A’) can mix.Minimal Dark Sector could consist of A’ only.

Dark sector

A’

Visible sector

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

6



one of the best motivated DP models

Need new U(1)

D

Slide7

Dark Photon

Search World

Map

Y2015 Status

: publishing, approved, proposalSunny Seo, IBSIBS-KMI Workshop 2020.08.247

Slide8

Dark Photon Search Experiments

Beam dump

Collider Exp.

Astrophysical Obs.

Fixed target

SN 1987A, Sun etc.e- beam: E137, KEK,

Orsay, E141, E774, NA64,

BDX, LDMX, HPSe+

beam

:

MMAPS, VEPP-3, PADME

g

beam

:

GlueX

, LEPS2, LEPS, and FOREST

p

beam

:

SHiP, NA62, FASER, REDTOP, SeaQuest

(thick target)

(thin target)

pp: LHCb

e+e-: Belle II, KLOE-2

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.248

Slide9

Sub-MeV A’

Search Status

S

imilar to

Axion/ALP search techniques,but magnet is not required for A’ <-> g conversion.Sunny Seo, IBS

9IBS-KMI Workshop 2020.08.24

Slide10

Sub-

G

eV A’ Search Status & Prospects

“Dark Sectors 2016 Workshop:

Community Report” In the near future, heavier mass ands

maller e regioncan be explored. DP

parameter space f

avored byanomalous muon g

m

-2

seems to be excluded

b

y most exp.

Sunny Seo, IBS

10

Slide11

Sub-

G

eV A’

Search

> GeV A’ Search

SHiP: 2x1020 POTSHiP can explore ~10 GeV region at

e ~ 10-7

- 10-8.

Sunny Seo, IBS

11

IBS-KMI Workshop 2020.08.24

Slide12

Yemilab

@

Handuk

iron mine

12

~1 km depthTo be completed in 2021

Sunny Seo, IBS

Slide13

LSC @

Yemilab

LSC = Liquid

Scintillator Counter

~3 kton

22m(

f

) x 28m(H)

LSC Hall

Pit:

20

m (D) x 20 m (H)

Sunny Seo, IBS

e

-

beam

e

-

beam

Slide14

Dark Photon Search Scheme

Detector

e

-

100 MeV

@1MW

A’ detection

3

) Absorption

2)

ggg

decay

1

)

e+e

- decay

(

E

det

> 200

keV

)

A’ decay

A’

 e+e

-A’  ggg

~3 kton LS targets

urrounded by buffer & veto

A’ Production"dark-

strahlung

"

process

Target

Shield

Decay distance

Absorption distance

LSC @

Yemilab

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

14

L

t/

sh

=

0.5

m

L

decay

=

20

m

L

detector

=

20 m

Slide15

Dark Photon Productions

e

-

beam

Dark photon

electronelectronnucleus

“Bremsstrahlung-like” process

a.k.a.

“dark-

strahlung

”

15

Liu & Miller: PRD 96, 016004 (2017)

Slide16

Dark Photon Production

by “dark-

strahlung”

d

s/(e2dx)[GeV-2]x = EA’/

EemA’ = 10 MeVmA’ = 1 MeV

m

A’ = 100 keV

m

A’

= 10

k

eV

m

A’

= 1

k

eV

IWW approximation

16

100 MeV

e- beam

on Tungsten targetSunny Seo, IBS

IBS-KMI Workshop 2020.08.24

Slide17

Dark Photon Detections

17

Absorption

A’

 e+ e- ( > 1 MeV)

Visible DecaysA’  ggg ( < 1 MeV)

Invisible

Decays

A’

c

c

-

Sunny Seo, IBS

Raggi

&

Kozhuharov

,

Nuovo

Cimento

V.38 n.10 (2015)

IBS-KMI Workshop 2020.08.24

Compton-like

Slide18

Liu

& Miller: PRD 96, 016004 (2017)

We should add an additional term of DP

absorption signal

to decay signal.

DP production x-section

only decay

signal

x

[1

–

exp

(

–

L

dec

/l

f

– L

det/ldet

)]decay

or absorption signal

w

here,Ldet: detector lengthldet: DP abs. length in detector

18

Production: “dark-

strahlung

”

Detection :

A’



e+e

- or 3

g

, or

A’ absorption

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

Liu

& Miller: PRD 96, 016004 (2017)

Expected

# of Dark Photons

Slide19

DP Sensitivity @

YemiLab

DP

“decay” signal onlyPreliminary

A’  e+e-A’ 

ggg

L

t/

sh

=

50 cm

(W)

L

decay

= 20 m

Excluded region

@95%

L

det

= 20 m

Sunny Seo, IBS19

Slide20

DP Sensitivity @

YemiLab

DP

“absorption” signal onlyPreliminary

Excluded region @95%Lt/sh =

50 cm (W)

Ldecay

= 20 m

L

det

= 20 m

Sunny Seo, IBS

20

Slide21

DP Sensitivity @

YemiLab

DP

“decay” + “absorption”

PreliminaryLt/sh = 50 cm

(W)

Ldecay = 20 m

L

det

= 20 m

Excluded region

@95%

Sunny Seo, IBS

21

Slide22

For light A’ ( < 1MeV),

g—A’

oscillation is possible (like

n oscillation

)Danilov, Demidov, GorbunovPRL 122, 041801 (2019)

Where, 1/G

: photon attenuation length in matter

m

f

>> m

g

: P =

e

2

m

f

<< m

g

: P =

e2

(mf /m

g)4

m

f = mg

: resonanceSunny Seo, IBSIBS-KMI Workshop 2020.08.24

22

mg

= 21 eV (water) 80 eV

(tungsten)

Slide23

arXiv:1812.02719

Demidov

,

Gninenko

, GorbunovSunny Seo, IBSIBS-KMI Workshop 2020.08.2423

Slide24

Oscillations @

Yemilab

case

g—A’

oscillation @ target (tungsten)A’—g oscillation @ detector (water)

+ ...

Photon flux per electron in matter

 See next

2 pages

Sunny Seo, IBS

24

Slide25

(1)

photon flux (1

st generation)

Eq. (24)

25Tsai & Whitis, Phys.Rev. 149 (1966) 1248-1257

Sunny Seo, IBSIBS-KMI Workshop 2020.08.24

Slide26

(2) Photon flux

(

2nd

generation)

Eq. (29)26

Tsai & Whitis, Phys.Rev. 149 (1966) 1248-1257Sunny Seo, IBS

Slide27

Using NIST database

27

Attenuation

lengths

1/G [cm]

EgG [eV2]

Eg [MeV]

Eg

[MeV]

Photon

Attenuation in Matter

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

Slide28



Best

direct DP search sensitivity in O(1 eV) <

Mf <

1 MeVg—A’ Oscillation Sensitivity

Resonance in water(21 eV)

Resonance in Tungsten

(80 eV)

Only Direct

Measurement Experiments

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

28

Preliminary

E

g

= 10 MeV

Slide29

Summary & Conclusion

In

Yemilab

, we could host a

n detector (~3 kton LS).There has been increased interest in DP searches and various experimental techniques/models exist.  Some interesting results are expected in the near future.

29 multi-purpose detector: dark photon, solar n, reactor

n, geo

n,…

Using the

n

detector (~3

kton

LS) in

Y

emilab

,

w/ 1 year operation of

100 MeV

e- beam (1 MW), DP kinetic mixing

parameter (e) sensitivities are obtained:

e2 ~ 10

-13 ( < 1MeV), e

2 ~ 10-17

( > 1MeV)preliminary

 Best direct DP search

sensitivity in O(1 eV) < Mf < 80 MeV

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

Slide30

Backup Slides

Sunny Seo, IBS

IBS-KMI Workshop 2020.08.24

30

Slide31

DP decay length

(

l

f

)

(m

f > 1 MeV)

(mf < 1 MeV)

31

w

here,

E

k

: DP energy

E

k

=

xE

e

(Continued…

)

Slide32

DP absorption length (

l

)

n

e

: electron number density of the shieldsabs: DP absorption x-section

w

here,

|k|:

DP 3

momentum

|q|:

g

3 momentum =

E

g

Sunny Seo, IBS

32

(Continued

…

)

Slide33

33

e

DP mass

(

mf )Decay length(lf)Absorption length (l

sh)In shieldAbsorption length (ldet)In detector10^-5

0.1 MeV

~1022 m (3g)

~10

9

m

~10

10

m

10^-5

10 MeV

< 1 m (

e+e

-)

~10

9

m

~1010 m

Lsh =

0.5 m, Ldecay = 20

m, Ldetector = 20 m

10^-3

0.1 MeV

~10

18

m

(3

g

)

~10

5

m

~10

6

m

10^-3

10 MeV

~10^-5

m (

e

+

e

-

)

~10

5

m

~10

6

m

100 MeV

e-

beam

Tungsten target (0.5 m), Water detector

10^-8

0.1 MeV

~10

28

m

(3

g

)

~10

15

m

~10

16

m

10^-8

10 MeV

~10

5

m (

e+e

-)

~10

15

m

~10

16

m

47



DP

absorption

is a dominant DP

interaction mode

for light DP

.

< 1 MeV



DP decay

is a dominant DP

interaction mode

for heavier DP

.

(Significant fraction of DP loss is possible at shield.)

>

1 MeV

Slide34

f



ggg

f

 e+e-

Absorp

tion

Detector

diameter

Sunny Seo, IBS

34

Preliminary

IBS-KMI Workshop 2020.08.24

Slide35

f



ggg

f

 e+e

-

Absorp

tion

Detector

diameter

Sunny Seo, IBS

35

Preliminary

IBS-KMI Workshop 2020.08.24

Slide36

f



ggg

f

 e+e

-

Absorp

tion

Detector

diameter

Sunny Seo, IBS

36

Preliminary

IBS-KMI Workshop 2020.08.24