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CKM Unitarity and Kaon Decays
Baksan 2007 Viacheslav Duk, INR RAS
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contents Viacheslav Duk, Baksan 2007
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contents CKM matrix Vud, Vus and Vub CKM unitarity: current status
Vus measurement: 4.1 Vus from kaon decays 4.2 Precise measurement of BR(Ke3) 5. Vud measurement 5.1 Vud from 0+→0+ transitions 5.2 Vud from neutron decay 6. Results summary 7. Conclusions Viacheslav Duk, Baksan 2007
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Vij - fundamental SM parameters precise determination is important
CKM matrix Vij - fundamental SM parameters VCKM = CKM - quark mixing matrix precise determination is important Viacheslav Duk, Baksan 2007
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Vij - fundamental SM parameters precise determination is important
CKM matrix Vij - fundamental SM parameters VCKM = CKM - quark mixing matrix precise determination is important CKM unitarity: VV+=1 Testing SM Probing New Physics (or constraining it) Viacheslav Duk, Baksan 2007
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Vij - fundamental SM parameters precise determination is important
CKM matrix Vij - fundamental SM parameters VCKM = CKM - quark mixing matrix precise determination is important CKM unitarity: VV+=1 Testing SM Probing New Physics (or constraining it) Best unitarity test: |Vud|2+|Vus|2+|Vub|2=1 Processes are easy for theoretical description Precise measurements are possible Viacheslav Duk, Baksan 2007
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Vud, Vus and Vub measurement
Superallowed 0+→ 0+ Fermi transitions Neutron β-decay n→p e ν pion β-decay π→π0eν Viacheslav Duk, Baksan 2007
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Vud, Vus and Vub measurement
Superallowed 0+→ 0+ Fermi transitions Neutron β-decay n→p e ν pion β-decay π→π0eν Vus Semileptonic kaon decays Leptonic kaon decays Hyperon decays Viacheslav Duk, Baksan 2007
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Vud, Vus and Vub measurement
Superallowed 0+→ 0+ Fermi transitions Neutron β-decay n→p e ν pion β-decay π→π0eν Vus Semileptonic kaon decays Leptonic kaon decays Hyperon decays Vub inclusive B-decays exclusive B-decays Viacheslav Duk, Baksan 2007
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Vud, Vus and Vub measurement
Superallowed 0+→ 0+ Fermi transitions Neutron β-decay n→p e ν pion β-decay π→π0eν Vus PDG06 values: |Vud| = ± |Vus| = ±0.0021 |Vub| = ±0.0030 Semileptonic kaon decays Leptonic kaon decays Hyperon decays Vub Vub can be neglected in unitarity condition inclusive B-decays exclusive B-decays Viacheslav Duk, Baksan 2007
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CKM unitarity: current status
two Vud values 0+→0+: 00Vud= (27) n→p e ν: nVud= (95) nVud - 00Vud=(2.4±1.0)*10-3 or 2.4σ Viacheslav Duk, Baksan 2007
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CKM unitarity: current status
two Vus values two Vud values 0+→0+: 00Vud= (27) n→p e ν: nVud= (95) nVud - 00Vud=(2.4±1.0)*10-3 or 2.4σ Old value: oldVus=0.2196(23) PDG03 New vlaue: newVus=0.2257(21) PDG06 newVus - oldVus=(0.61±0.31)*10-3 or 2.0σ Viacheslav Duk, Baksan 2007
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CKM unitarity: current status
two Vus values two Vud values 0+→0+: 00Vud= (27) n→p e ν: nVud= (95) nVud - 00Vud=(2.4±1.0)*10-3 or 2.4σ Old value: oldVus=0.2196(23) PDG03 New vlaue: newVus=0.2257(21) PDG06 newVus - oldVus=(0.61±0.31)*10-3 or 2.0σ Unitarity condition: |Vud|2+|Vus|2 +|Vub|2 =1 - Δ |oldVud|2 + |oldVus|2 + |oldVub|2 = (14) Δ=0.0035(14) σ |00Vud|2 + |new Vus|2 + |newVub|2 = (15) Δ=0.0008(15) σ |nVud|2 + |oldVus|2 + |oldVub|2 = (21) Δ=0.0011(21) σ |nVud|2 + |new Vus|2 + |newVub|2 = (28) Δ= (28) -1.4σ Viacheslav Duk, Baksan 2007
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CKM unitarity: current status
two Vus values two Vud values 0+→0+: 00Vud= (27) n→p e ν: nVud= (95) nVud - 00Vud=(2.4±1.0)*10-3 or 2.4σ Old value: oldVus=0.2196(23) PDG03 New vlaue: newVus=0.2257(21) PDG06 newVus - oldVus=(0.61±0.31)*10-3 or 2.0σ Unitarity condition: |Vud|2+|Vus|2 +|Vub|2 =1 - Δ |oldVud|2 + |oldVus|2 + |oldVub|2 = (14) Δ=0.0035(14) σ |00Vud|2 + |new Vus|2 + |newVub|2 = (15) Δ=0.0008(15) σ |nVud|2 + |oldVus|2 + |oldVub|2 = (21) Δ=0.0011(21) σ |nVud|2 + |new Vus|2 + |newVub|2 = (28) Δ= (28) -1.4σ One should select more reliable results Viacheslav Duk, Baksan 2007
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Trying to understand 2σ deviation between old and new magnitude
Vus measurement Choosing the most reliable process for Vus extraction Trying to understand 2σ deviation between old and new magnitude Viacheslav Duk, Baksan 2007
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Vus from different processes
Good agreement PDG average is based on Vus from K→eνπ0 (Ke3) Viacheslav Duk, Baksan 2007
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Vus from kaon decays K→eνπ0 (Ke3) New results are more reliable
Most precise measurement of Vus – from BR(Ke3) old experiments (PDG03): BR(Ke3)=(4.86±0.06)*10-2 5K events new experiments (PDG06): BR(Ke3)=(4.98±0.07)*10-2 71K events New results are more reliable Viacheslav Duk, Baksan 2007
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Vus from charged kaon decay K→eνπ0 (Ke3)
ISTRA+(INR/IHEP): most precise measurement SEW=1.0232(3) – short-distance radiative correction δSU2 =(2.3±0.2)* SU(2) breaking correction δe+=(-0.1±0.16)*10-2 – long-distance QED correction f+(0) =0.961±0.008 – form factor Main theoretical uncertainties are from f+(0) and δe+ Viacheslav Duk, Baksan 2007
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Vus from charged kaon decay K→eνπ0 (Ke3)
ISTRA+(INR/IHEP): most precise measurement BR(Ke3) is measured 2M events! SEW=1.0232(3) – short-distance radiative correction δSU2 =(2.3±0.2)* SU(2) breaking correction δe+=(-0.1±0.16)*10-2 – long-distance QED correction f+(0) =0.961±0.008 – form factor Main theoretical uncertainties are from f+(0) and δe+ Viacheslav Duk, Baksan 2007
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|Vus|=0.2275±0.0024 Vus from charged kaon decay K→eνπ0 (Ke3)
ISTRA+(INR/IHEP): most precise measurement BR(Ke3) is measured 2M events! SEW=1.0232(3) – short-distance radiative correction δSU2 =(2.3±0.2)* SU(2) breaking correction δe+=(-0.1±0.16)*10-2 – long-distance QED correction f+(0) =0.961±0.008 – form factor |Vus f+(0)|=0.2186±0.0009(BR)±0.0012(th) |Vus|=0.2275±0.0009(BR)±0.0022(th) |Vus|=0.2275±0.0024 Main theoretical uncertainties are from f+(0) and δe+ Viacheslav Duk, Baksan 2007
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Trying to understand 2.4σ deviation between 00Vud and nVud magnitudes
Vud measurement Choosing the most reliable process for Vud extraction Trying to understand 2.4σ deviation between 00Vud and nVud magnitudes Viacheslav Duk, Baksan 2007
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Vud from different processes
Discrepancy between 00Vud and nVud PDG average is based on Vud from 0+→0+ transitions Viacheslav Duk, Baksan 2007
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Vud from superallowed 0+→0+ transitions
Pure vector transition (no axial component) Most reliable way to extract Vud Viacheslav Duk, Baksan 2007
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Vud from superallowed 0+→0+ transitions
Pure vector transition (no axial component) Most reliable way to extract Vud Viacheslav Duk, Baksan 2007
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Vud from superallowed 0+→0+ transitions
Pure vector transition (no axial component) Most reliable way to extract Vud RC – electroweak radiative corrections (from 3.1% to 3.6% for different nuclei) f – phase space factor t – half-life time PDG06: 00Vud= (27) Viacheslav Duk, Baksan 2007
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Vud from neutron decay n→peν
Compared with Vud from 0+→0+ smaller theoretical uncertanities more difficult experimental procedure Viacheslav Duk, Baksan 2007
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Vud from neutron decay n→peν
Compared with Vud from 0+→0+ smaller theoretical uncertanities more difficult experimental procedure Viacheslav Duk, Baksan 2007
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Vud from neutron decay n→peν
Compared with Vud from 0+→0+ smaller theoretical uncertanities more difficult experimental procedure measured quantites: τn – from neutron decay (see next slide) λ – from asymmetry A0= - 2λ(λ+1)/(1+3λ2) f – phase space factor τn – neutron life time ΔR~1.5% – model-dependent internal radiative correction δR~2.4% – model-independent external radiative correction K=h*2π3(hc)6/(mec2)5 λ=GA/Gv PDG06: λ= (29) PERKEO 2005: λ= (13) more precise Viacheslav Duk, Baksan 2007
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The most close extrapolation to neutron lifetime (5 s only)
Precise measurement of neutron life time Gravitational storage of UCN τ=878.5±0.8 s A.P.Serebrov et al 2005 The most close extrapolation to neutron lifetime (5 s only) New value of τ is in better agreement with cosmology Viacheslav Duk, Baksan 2007
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New Physics contribution to nVud
Vud : n→peν vs 0+→0+ 0+→0+ n→peν 00Vud is the most reliable value nVud ≠ 00Vud nVud is determined by τn and λ τn is confirmed by cosmology wrong value of λ or New Physics contribution to nVud Viacheslav Duk, Baksan 2007
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|Vud|2+|Vus|2+|Vub|2=0.9992(15)
Results summary Unitarity condition: |Vud|2+|Vus|2+|Vub|2=1 |Vub|=0.0043(3) can be neglected Most reliable |Vus| from kaon decays |Vud| from 0+→0+ transitions |Vud|2+|Vus|2+|Vub|2=0.9992(15) |Vud| can also be extracted from n→peν using τ and λ measurements New τ is confirmed by cosmology New λ value |nVud|≠|00Vud|, |nVud|2+|Vus|2+|Vub|2=1.0038(28) Δ=-1.5σ Wrong magnitude of λ or New Physics ? Viacheslav Duk, Baksan 2007
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Unitarity condition |Vud|2+|Vus|2+|Vub|2=1 is a good test of SM
Conclusions Unitarity condition |Vud|2+|Vus|2+|Vub|2=1 is a good test of SM Vud is extracted from 0+→0+ transitions, Vus – from kaon decays, Vub is small Most reliable results on Vud, Vus and Vub confirm CKM unitarity Vud can also be obtained from neutron decay using τ and λ measurements Vud extracted from neutron decay violates unitarity condition by 1.5σ New measurements of τ and λ are needed Viacheslav Duk, Baksan 2007
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Thank you! Baksan 2007 Viacheslav Duk, INR RAS
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