Physics with the KLOE2 experiment at DAΦΦNE• Machine and detector upgrade• CKM precision measurements• Interferometry• Dark matter seachKLOE-2 at upgraded DAΦΦNEUpgrade of DAΦNE in luminosity:
Crabbed waist scheme at DAΦNE (proposal by P. Raimondi)- increase L by a factor O(5)- Successful experimental test at DAΦNE- requires minor modifications- relatively low cost

KLOE-2 Plan:{- phase 0: KLOE restart taking data end 2009 with a minimalupgrade (L~5 fb-1)- phase 1: full KLOE upgrade (KLOE-2) > 2011 (L>20 fb-1)

Physics issues:• Neutral kaon interferometry, CPTsymmetry & QM tests• Kaon physics, CKM, LFV, rare KS decays• Dark matter• η,η’ physics• Light scalars, γγ physics• Hadron cross section at low energy, muon
anomaly

Detector upgrade issues:• Inner tracker R&D• γγ tagging system• FEE maintenance and upgrade• Computing and networking update• etc.. (Trigger, software, …)

DAΦ
DAΦNE Beam distributions @ IPDAΦΦNE KLOEDAΦΦNE DAΦΦNEKLOE UpgradeDAΦΦNE UpgradeIbunch (mA)1313

Nbunch110110βy* (cm)

1.7

0.65

βx* (cm)

170

20

σy* (µµm)72.6

σx* (mm)

0.7

0.2

σz (mm)2520

θcross/2 (mrad)

12.5

25

ΦPiwinski

0.45

2.5

L (cm-2s-1) x1032

1.5>5

Luminosity vs tunes scan
Crab Off

Crab On  0.6/θ
0.2

0.2

0.18

0.18

0.16

0.16

0.14

0.14

0.12

0.12

0.1

0.1

0.08

0.08

0.06

0.06
0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

0.06

0.08

0.1

0.12

0.14

0.16

Lmax = 2.97x1033 cm-2s-1Lmax = 1.74x1033 cm-2s-1

Lmin = 2.52x1032 cm-2s-1

Lmin = 2.78x1031 cm-2s-1

0.180.2

DAΦ
ΦNE Luminosity versus colliding currents}

NEW COLLISION SCHEME:
Large Piwinski angle
Crab-Waist compensation SXTs

original collision schemefrom P. Raimondi’s talkγγ taggers

HETLET

The HET detector consists in a position
detector with a pitch of few millimeter(¾E ~ 0.6 MeV/mm). The characteristics of thisdetector are the following: Good time resolution to disentangle eachbunch (~2.7 ns bunch spacing); Capability to acquire data at a frequency of
368 MHz in order to permit event

The LET detector consists of a calorimeter capable of detecting electrons and positrons within a wide energy range peakedaround 200 MeV. The environmental conditions require radiation-tolerant devices, insensitive to magnetic fields. The
physical requirements are the following: Good energy resolution to improve the reconstruction of the γγ invariant mass from the decay products;
 Good time resolution to associate detected events with the proper bunch crossing; Small size.

Inner tracker at KLOE
5 independent tracking layers for a fine vertex reconstruction of KS and η
200 µm σrφ and 500 µm σZ spatial resolutions with XV readout
700 mm active lengthfrom 150 to 250 mm radii
1.8% X0 total radiation length in the active region
Realized with Cylindrical-GEM detectors

Kaon physics
 Set bounds on New Physics from LeptonLepton-Quark Universality
 Precise determination of Vus
 Test of Lepton universality Ke3 vs Kµ3
 Most precise test of CKM unitarity
New Physics extensions of the SM can break gauge universality in the form of tree or loop leveli. Exotic Muon Decays
Decays: would contribute to the muon lifetime
contributions to muon decays and/or semileptonic processes.
222

Vud + Vus + Vub = 1 - BR(exotic muon decays)
Provides best limit on
BR (µ + → e + νe ν µ ) ∼ 10 better than direct searchii. Additional Z’ Gauge Bosons,Bosons contributing at loop level to muons and semileptonic decays
differently (Competitive
Competitive with direct search)search[ PRD 35 (1987)]
iii. SUSY particle loops affecting muon and semileptonic decays differently: constraints onslepton--squark mass difference (x2-3 precision needed)
slepton[PRL 75 (1995) , PRL 88 (2002)]

Present accuracy set bounds on the scale of New Physics ΛNP at 1-2 TeV
222Vud + Vus + Vub = 1 + ε NP

ε NP ≈ M 2W /Λ2NP

Vus, lepton universality and CKM unitarity at KLOE
Γ(K → πlν(γ)) ∝ |Vus|2 |f+Kπ(0) |2IlK(λ+,λ0,0) (1 + δlK)

All KLOE exp. inputs but KS lifetime
KLOE average @ 0.28%|Vus|f+(0) = 0.2157(6)err %|Vus| = 0.2237(13)0.6%rµe = 1.000(8)χ2/ndf=7/4(13%)∝|Vus /Vud|= 0.2323(15)

1-|Vud |2 -|Vus|2 = 4(7)x10-4 @0.6σσWorld Average: 6x10-4 accuracy

|Vus|f+(0) present world average (WA)
Γ(KΓ( l3(γγ)) =CK2 GF2MK5192π30 −Kπ
2SEW |Vus| | f+ (0)||2 IKℓ(λ+,0) (1+δδKSU(2)+δδKℓem)2% err BR

τδ

IKℓ

KLe3

0.21652(56)0.25 0.11 0.20 0.11 0.10

KLµ30.21746(69)0.32 0.17 0.19 0.11 0.15

KSe30.21572(132)0.61 0.60 0.03 0.11 0.10+/−e3 0.21624(113)K+/−

0.52 0.31 0.06 0.41 0.09+/−µ3 0.21676(141)K+/−

0.65 0.48 0.06 0.41 0.15
can be improved

Average: |Vus| f(0) = 0.21660(47)χ2/ndf 3.03/4 (55%)

|Vus|f+(0): KLOE+Step0+WA
Γ(KΓ( l3(γγ)) =CK2 GF2MK5192π30 −Kπ2
SEW |Vus| | f+ (0)||2 IKℓ(λ+,0) (1+δδKSU(2)+δδKℓem)2Approx. contr. to % err from:% err

BRKLe3 0.2155(4)0.210.09 0.13 0.11 0.09KLµ30.2167(5)0.25

0.10 0.13 0.11 0.15

KSe3 0.2153(7)0.33

0.30 0.03 0.11 0.09

K±e3 0.2152(8)0.380.25 0.12 0.25 0.09

K±µ3 0.2132(9)0.42

0.27 0.12 0.25 0.15

Fractional error on |Vus|f+(0) is 0.14%
World Average is 0.23%

τδ

IKℓ

Universality: KLOE+Step0+WA
 Today with f+ (0) @ 0.5% the accuracy on the unitarity relation of
the first row isσ (1-Vud 2 -Vus 2 ) = 6 x10-4

 f+ (0) @ 0.1% accuracy from lattice within few years
f+ (0)VusVus

KLOE today

0.28%

0.30%

(World Average)(0.23%)(0.25%)KLOE + Step0 + WA

0.14%

0.17%

 With |Vud | @ 0.02% and |Vus| @0.17% the accuracy on the unitarity relationof the first row would improve by a factor of ∼2σ (1-Vud 2 -Vus 2 ) = (3÷÷4) x10-4

Neutral kaon interferometry[1i =K0 K 0 − K 0 K02π+π−π+φt1]t2π−N(∆t)∆t=|t1-t2|

Most precise test of quantum coherencein an entangled system:

EPR correlation:
no simultaneous decays(∆t=0) in the same
final state due to thedestructive QM interferenceζ 00 = (1.4 ± 9.5STAT ± 3.8SYST )×10−7
ζ decoherence parameter (QM predicts ζ=0)

Quantum gravity effects might induce:
1) decoherence and CPT violation(at most γ=O(mK2/MPlanck)~2x10-20
GeV)2) modification of the initial correlationof the kaon pair(at most ω=O(mK2/MPlanck/∆Γ) ~1x10-3

γ = (0.7 ±1.2STAT ± 0.3SYST )×10−21 GeV() (i ∝ K 0K 0 − K 0K 0 + ω K 0K 0 + K 0K 0(ℑω = (−1.7))×10ℜω = −1.6+−32..01STAT ± 0.4SYST ×10−4+3.3−3.0 STAT

±1.2SYST−4)

Interferometry at KLOE-2: φ →KSKL→π+π− π+π−I(π+π−, π+π−;∆t) (a.u.)

Possible signal of decoherence
concentrated at very small ∆tI(π+π−, π+π−;∆t) (a.u.)
Black hist. :σ(∆t)~1τS => 6mm (KLOE)

ζ 00 = 4 ×10−6Red hist:σ(∆t)~1/4 τS => 1.5mm(KLOE + inner tracker)
Blue curve: idealζ 00 = 0∆t/τS∆t/τSTheoretical distribution

Reconstructed distribution (MC)Perspectives with KLOE-2 at upgraded DAΦ
ΦNE
Mode

Test ofParam.

Present best publishedmeasurement

KLOE-2
L=50 fb-1

KS→πeν

CP, CPTAS(1.5 ± 11) × 10-3

± 1 × 10-3π+π− πeν

CP, CPTAL( 3322 ± 58 ± 47 ) × 10-6± 25 × 10-6π+π− π0π0CP

Re(ε’/ε)(1.65 ± 0.26) × 10-3 (*)± 0.2 × 10-3π+π− π0π0CP, CPT

Im(ε’/ε)(-1.2 ± 2.3) × 10-3± 3 × 10-3πeν πeν

CPTRe(δ)+Re(x)Re(δ) = (0.25 ± 0.23) × 10-3(*)
Re(x-) = (-4.2 ± 1.7) × 10-3(*)± 0.2 × 10-3πeν πeν

CPTIm(δ)+Im(x+)Im(δ) = (-0.6 ± 1.9) × 10-5(*)
Im(x+) = (0.2 ± 2.2) × 10-3(*)± 3 × 10-3∆m(5.288 ± 0.043) × 109 s-1± 0.03 × 109 s-1π+π− π+π−(*) = PDG 2008 fit(*) = PDG 2008 fit(*)

Perspectives with KLOE-2 at upgraded DAΦ
ΦNE
Mode

Test ofParam.

Present best
publishedmeasurement

KLOE-2
L=50 fb-1

π+π− π+π−QM

ζ00(1.0 ± 2.1) × 10-6± 0.1 × 10-6π+π− π+π−QM

ζSL(1.8 ± 4.1) × 10-2± 0.2 × 10-2π+π− π+π−

CPT & QM

α(-0.5 ± 2.8) × 10-17
GeV± 2 × 10-17 GeV

π+π− π+π−CPT & QM

β(2.5 ± 2.3) × 10-19
GeV± 0.1 × 10-19 GeV

π+π− π+π−

CPT & QMγ(1.1 ± 2.5) × 10-21
GeV± 0.2 × 10-21 GeV
compl. pos. hyp.
± 0.1 × 10-21 GeV

π+π− π+π− CPT & EPR corr.

Re(ω)(1.1 ± 7.0) × 10-4± 2 × 10-5π+π− π+π− CPT & EPR corr.

Im(ω)(3.4 ± 4.9) × 10-4

± 2 × 10-5

KS,L→πeν

CPT & Lorentz∆ a0[(0.4 ± 1.8) × 10-17GeV]± 2 × 10-18 GeV

π+π− π+π−

CPT & Lorentz∆aZ[(2.4 ± 9.7) × 10-18GeV]± 7 × 10-19 GeV

π+π− πeν

CPT & Lorentz∆aX,Y[<10-21 GeV]

± 4 × 10-19 GeV

Dark Matter Perspective searches
Several recent puzzling astrophysical observations(PAMELA, ATIC, INTEGRAL, DAMA) can be interpreted bypostulating the existence of some secluded gauge sectorwith a rich phenomenology at low (O(1 GeV)) energies.
Some basic papers on the issue are:
1.
2.
3.
4.
5.
6.

C. Boehm, P. Fayet: Nucl. Phys. B (2004) 219-263
N. Borodatchenkova et al. : Phys. Rev. Lett. 96 (2006) 141802
M. Pospelov: arXiv:0811.1030
N. Arkani-Hamed et al.: arXiv:0810.0713
B. Batell et al.: arXiv:0903.0363
R. Essig et al.: arXiv:0903.3941

Hidden valley model
These models postulate a hidden valley, well separated
from the world with which they only occasionally get in touch

Here, the secluded particles mix with the Standard Modelones through some mechanism with mixing parameter k oforder up to 10–2 – 10–3 Interestingly enough much lower
values for k are disfavoured by cosmological considerationk(from reference 6)

T channel production
The U boson can be observed through the radiative
process: e+e–→ Ug →l+l– (l=e,m)e–γe+UThe cross section for this process is suppressed wrt theQED continuum by a factor
k2, so it can be at most ≈ 1pbThe two leptons however resonate about the U mass, whilethe QED continuum events do notS channel production
Probably the most interesting mechanism for secluded
particles production is the higgs’-strahlung: e+e–→ U h’,which can have a cross section of order 1 pb at DAFNE
energies
h’
e–
U*e+

U

If mh’ < mu then the higgs’ is relatively long-lived, O(10–9 s)thus escaping detection inside KLOE
The resulting signal (again assuming that the U decays onlyto SM particles) would then be a pair of leptons + missing
energyExperimental detection
The two produced leptons have energies high enough totrigger the events with efficiencies > 90% for almost all
possible combinations of mU and mh’, at least for theelectron channel
A possible background specific to DAFNE is KS → π+π–,with the parent KL flying through the apparatus
This should be a problem only for the muon channel and formasses of the U boson close to mK. It can however be wellcalibrated by using K crash events
If it turns out to be still a problem one can always think torun at √s < 2mK

Spectacular final states
If mh’ > 2 mU then the higgs’ decays mainly into two Ubosons giving rise to spectacular 4 leptons+g or 6 leptons
final states
Ue–Uh’

U*e+Ue–

γe+h’UU

Conclusions
| Vus|f+(0) @ 0. 14%(5 fb-1 are enough to do the job).

 Unitarity test at few 10-4 , with lattice improvements on form factors.
 Improve constraints on New Physics and interplay with other sectors.
 at the moment all KLOE results are compatible with no CPT violation.
 Neutral kaon interferometry, CPT symmetry and QM tests are among

the main issues of the KLOE-2 physics program. Measurements will
benefit from both a huge data sample (20-50 fb-1) and a better detector.
 moreover…. KLOE-2 can cover an interesting region of the dark matterparameter space in terms of the mixing parameter with the“standard sector” and mass.