1

Search for one large extra dimension with the DELPHI

detector at LEP

2009/5/25 論文会

M1 齋藤智之

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

Eur. Phys. J.C (2009) 60:17-23

2

Hierarchy problem

The experimental results including LEP greatly agree with the Standard Model.

But, there are some theoretical problems in the SM.

The hierarchy problem

: Gravity is too weak

Planck mass Electroweak symmetry breaking scale

Too large

The New Physics is needed

3

Extra dimensionLarge (flat) Extra Dimension (ADD)

–4+n dimensions (n>2, n=1,2 is excluded by direct gravity tests)–The gravity travels throghout the extra dimensions → KK Graviton

Warped Extra Dimension (RS)–4+1 dimensions–The gravity travels throughout the extra dimensions　　　　　→ KK Graviton

SM brane

Planck brane

Extra Dimension (Bulk)

Extra DimensionSM brane

Graviton

4

ADD model +

The ADD model test was peformed the mode for n≥2 at LEP and Tevatron

No excess with SM predictions

at the 95% CL

•　 This model is slightly warped but large ED

ADD model + IR cut-offADD model + IR cut-off

•　 For n small, this model evades the constrains

5

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

DELPHI

ALEPH OPAL

L3

EM CAL :

ALEPH

DELPHI

OPAL

6

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

DELPHI detector

① 45°<<135°

② 12°<<32°

② 148°<<168°

③ 3.8°<<8°

③ 172°<<176.2°

② Forward Electro Magnetic Calorimeter

③ Small Angle Tile Calorimeter

① High-Density Projection Calorimeter

Radius : 5 m

Weight : 3500 t

7

•　 r = 208-260 cm, |z| = 254 cm,•　 Granularity : 1degree in phi, 4 mm in z•　 Angular resolution : mrad in θ　 　　　　　　　　　　　　　　　　　　　　　　　　　 mrad in •　 Energy resolution :

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

High-density Projection Chamber(HPC)：measure the three-dimensional charge distribution

52 cm

47 cm

90 cm

Lead

Gas

8

Forward Electro Magnetic Calorimeter (FEMC)

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

•　 5 m diameter disk with 9064 lead glass blocks•　 granlarity : 55 cm ~ 1degree 1 degree•　

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

9

< 2.2°, < 0.8 GeV within 3°, 15°, 20° 　 from the highest energy photon　 in the STIC, FEMC, HPC respectively

Data preselection(single photon event)

HPC 　　　 > 0.06 FEMC 　　 > 0.10 STIC 　　　 > 0.30

•

To remove the mode

Why different value?

The cross section decreases with increasing energy and polar angle of photon.

•　 Of more than one photon events

Then the events accept the single photon events

10

of selected single photon

: the expected distribution from

: the data of single photon

: the signal expected from

for n=1 and =1.25 TeV/c 2

LEP energy : 180 ~ 209 GeV

overall luminosity : ~ 650

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

cosmic ray, collision,

This data are well compatible with expectations from SM processes

11

Results

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

+ detector effects (efficiency, energy resolution)

In order to agree with this data,

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

with

(n=1)

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅBThe fundamental mass scale

at 95 % CL(n=1)

12

Results

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

+ detector effects (efficiency, energy resolution)

In order to agree with this data,

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

with

(n=1)

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅBThe fundamental mass scale

at 95 % CL(n=1)

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

13

Conclusion

In order to study with n=1 large ED ,

we have re-analysised single-photon events

with DELPHI at LEP at √s=180~209 GeV.

•　 The mesuared single photon cross sections are in agreement with the expectations from SM processes

•　 The absence of excesses of events sets of a limit of 1.69 TeV/c at 95 % CL on with n=1 ED

14

Backgrounds

15

Of the photons,

40%→convert before they reach the HPC

7%→convert in front of the TPC ( → 　　　 )

A useful fraction of these can be reconstructed very precisely.

An energy precision : 1.2 %

A derectional precision : 1.2 mrad in and

The conversion radius : 5 mm

• In order to select well measured charged particle tracks,

•　 0.4 GeV < p < 100 GeV

•p/p ≤ 1.0 •　 measured track length ≥ 30 cm

•　 distance to I.P. in r plane ≤ 4 cm•　 distance to I.P. in z ≤ 4 cm

16

Small angle TIle Calorimeter(STIC)

160 tiles

Energy resolution : 3 % at 45 GeV

Spacil resolution : 1.5 degrees in phi , 1 mm in radius

Scintillator tiles

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

QuickTime˛ Ç∆TIFFÅiîÒà≥èkÅj êLí£ÉvÉçÉOÉâÉÄ

ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB