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GUT SCALE THRESHOLD EFFECTS ON PROTON DECAY 1 Takumi KUWAHARA - - PowerPoint PPT Presentation
GUT SCALE THRESHOLD EFFECTS ON PROTON DECAY 1 Takumi KUWAHARA - - PowerPoint PPT Presentation
GUT SCALE THRESHOLD EFFECTS ON PROTON DECAY 1 Takumi KUWAHARA Nagoya University SUSY 2016 Based on arXiv:1503.08561 NPB 898 (2015) with J.Hisano and Y.Omura (Nagoya U.) arXiv:1603.03568 NPB 910 (2016) with B.Bajc (J.Stefan inst.), J.Hisano
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Supersymmetric Grand Unified Theories (SUSY GUTs) => Predicting Baryon-Number Violating Processes (Proton Decay etc..) The promising extension of the SM …
Precise prediction towards discovery
strong and electro-weak interactions quarks and leptons Unified description of * B# is accidentally preserved in SM * Signature of BSM if we find
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Introduction SUSY SU(5) GUTs Proton Decay Procedure & Results Summary
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SUSY SU(5) GUTs
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SUSY SU(5) GUTs Gauge Sector
V(24) = ✓ G X† X W ◆
−
1 2
√
15 ✓ 2
−3
◆ B
DC, L ∈ Φ, UC, Q, EC ∈ Ψ
- N. Sakai (1981) S.Dimopoulos H.Georgi (1981)
Matter Sector: completely embedded in 5* (Φ) and 10 (Ψ) Matter and Gauge sectors are almost universal in the SUSY SU(5) GUTs Higgs Sector
H(5) = ✓ HC Hd ◆ , H(5) = ✓ HC Hu ◆
+ GUT breaking Higgs, and etc.. MSSM Higgs doublets are embedded in fields in (anti-)fundamental reps. So, Higgs sector depends on models
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Higgs Sector (besides 5+5* Higgs containing MSSM Higgses) Adjoint (24-dimensional) Higgs Minimal SU(5) Blue Higgses: GUT breaking one Missing Partner Model 50+50* 75-dimensional Higgs Models for Yukawa Realization additional 45+45* etc..
Masiero, Nanopoulos, Tamvakis, Yanagida (1982)
Grinstein (1982) Georgi, Jarlskog (1979) et al.
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Higgs Sector (besides 5+5* Higgs containing MSSM Higgses) Minimal SU(5) Missing Partner Model In this talk, I focus on * Simple * Still valid in high-scale SUSY Scenario (D=5 decay) * with fine-tuning in doublet-triplet splitting * Solving doublet-triplet splitting without fine-tuning * Models requiring huge number of fields => prospect for large quantum correction to proton decay prediction * Free from D=5 proton decay (if imposing Peccei-Quinn symmetry)
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Proton Decay
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CURRENT FUTURE p->π0+e+ 1.67×1034yrs 1.0×1035yrs
Current lower bound (future sensitivity) on proton decay. V(24) = ✓ G X† X W ◆
−
1 2
√
15 ✓ 2
−3
◆ B Main decay mode: p → π0 + e+ X bosons give rise to baryon-number violating process! p π0 e+ X Super-K Result 2016 Moriond Hyper-K Prospect 10-years exposure Proton Decay induced by gauge-interaction: in general, model (= Higgs sector) independent decay
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Theoretical progress (Higher-order corrections to Wilson coeff. of D=6 operators)
QCD correction (2-loop) RGE in SM (2-loop) RGE in SUSY SM (2-loop) Threshold Corrections
Arafune, Nihei (1994) Hisano, Kobayashi, Nagata, Muramatsu (2013) Daniel, Penarrocha (1984)
RGE effects are computed @ 2-loop order (Gauge interaction) 1-loop threshold corrections are also expected as the same order In addition, Hadron Matrix Elements @ 2GeV are calculated by lattice simulation with 30% errors
Aoki, Shintani, Soni (2013)
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Results
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C(0)
1
= C(0)
2
= − g2
5
M2
X
O(0)
1
= eabgersUC†aDC†bQr gLs O(0)
2
= eabgersEC†UC † aQbrQsg
In the Effective theory (~ MSSM),
Threshold corrections to Wilson coeff. λ(I) For each threshold corrections, we obtain; Vacuum polarization Vertex + Box
Analytic formula for Threshold Corrections
Vacuum polarization strongly depends on GUT mass spectrum Hisano, TK, Omura (2015)
λ(1) = Σ(0) M2
X + Σ(0) +
g2
5
16π2 16 5 1 − ln M2
X
µ2 ! , λ(2) = Σ(0) M2
X + Σ(0) +
g2
5
16π2 18 5 1 − ln M2
X
µ2 ! .
Ldim.6 =
Z
d4q ∑
I=1,2
(1 − l(I))C(0)
I O(0) I
+ h.c.
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(Ratio) ≡
Γ(p → π0 + e+)
- w
Γ(p → π0 + e+)|w/o
Comparing with the previous study
Ratio of decay rate with and without threshold corrections
Minimal SU(5) Missing-Partner SU(5) Ratio 0.994 0.394 τ(p→e+π0) 2.23×1036yrs 7.09×1035yrs
α−1
i
(µ) = α−1
G (µ) + λi(µ)
Unified coupling MSSM couplings Depends on GUT Scale Masses
Determination of GUT Mass Spectrum
Numerical Results: among the GUT models (MX = 2×1016GeV)
Constraining on * Color-triplet Mass * MX2M∑ Suppressed rate <= thanks to threshold effects Short lifetime <= Large unified coupling @GUT scale due to many fields Bajc, Hisano, TK, Omura (2015)
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Summary
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We have derived 1-loop threshold correction to Wilson coefficients of Dim.-6 operators at GUT scale. Proton lifetime becomes longer about a few % due to threshold corrections in the minimal SUSY SU(5). Large suppression of decay rate in the missing-partner SU(5) model (due to many fields and mass splitting)
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Backups
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SUSY SU(5) GUTs and Its Spectrum
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Minimal SUSY SU(5) GUT
ΦA(5) = ✓ DC
a
ersLs ◆ , ΨAB(10) = ✓ eabcUC
c
Qas
−Qbr
ersEC ◆
Matter Sector Gauge Sector Higgs Sector
V(24) = ✓ G X† X W ◆
−
1 2
√
15 ✓ 2
−3
◆ B
H(5) = ✓ HC Hd ◆ , H(5) = ✓ HC Hu ◆
Σ24 = ✓ Σ8 Σ(3,2) Σ(3∗,2) Σ3 ◆
+
1 2
√
15 ✓ 2
−3
◆ ΣS
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Minimal SUSY SU(5) GUT
K24 = (Σ†
24)A B (e2g5V)B C(e−2g5V)D A(Σ24)C D,
→
MX = 5g5v24 h(Σ24)r
si = 3v24δr s,
D
(Σ24)α
β
E
= 2v24δα
β
W = λH(Σ24 + 3v24)H,
→
MHC = 5λv24
W = f 3 Tr(Σ24)3 + m24 2 Tr(Σ24)2
→ W = m8
2 ΣA
8 ΣA 8 + m3
2 ΣA
3 ΣA 3 + mS
2 ΣSΣS + · · ·
m8 : m3 : mS = 5m24/2 : 5m24/2 : m24/2
= 5 : 5 : 1
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Missing-Partner SU(5) D
(Σ75)[rs]
[tu]
E
= 3
2v75(δr
tδs u − δr uδs t),
D
(Σ75)[αβ]
[γδ]
E
= 1
2v75(δα
γδβ δ − δα δ δβ γ),
D
(Σ75)[αr]
[βs]
E
= −1
2v75δα
βδr s,
K75 = (Σ†
75)[AB]
[CD](e2g5V)C
E(e2g5V)D F (e−2g5V)G A(e−2g5V)H B (Σ75)[EF]
[GH].
→
MX = 2
√
6g5v75
W = MHC HCH0
C + MH0
C H0
CHC, MHC ⌘ 48v2
75
MPl gHg0
H,
MHC ⌘ 48v2
75
MPl g0
HgH.
with after integrating out 50+50* typically, ~1015 GeV
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Missing-Partner SU(5) D
(Σ75)[rs]
[tu]
E
= 3
2v75(δr
tδs u − δr uδs t),
D
(Σ75)[αβ]
[γδ]
E
= 1
2v75(δα
γδβ δ − δα δ δβ γ),
D
(Σ75)[αr]
[βs]
E
= −1
2v75δα
βδr s,
75 = (1, 1)0 ⊕ (3, 1)− 5
3 ⊕ (3, 1) 5 3 ⊕ (3, 2) 5 6 ⊕ (3, 2)− 5 6 ⊕ (6, 2) 5 6 ⊕ (6, 2)− 5 6 ⊕ (8, 1)0 ⊕ (8, 3)0
= 2 : 4 : (NG Mode) : 2 : 1 : 5
M(8,3)0 = 5m75
with
W = m75(Σ75)[CD]
[AB](Σ75)[AB] [CD] − 1
3λ75(Σ75)[AB]
[EF] (Σ75)[CD] [AB](Σ75)[EF] [CD]
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Constrained Mass Spectra
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By using central values for couplings (& sparticles around 1 TeV)
3 g2
2(µ) −
2 g2
3(µ) −
1 g2
1(µ) =
1 8π2 12 5 ln MHC µ , 5 g2
1(µ) −
3 g2
2(µ) −
2 g2
3(µ) =
1 8π2 12 ln M2
XMΣ24
µ3 . 3 g2
2(µ)
2 g2
3(µ)
1 g2
1(µ) =
1 8π2 12 5 ln MHC MHC MH0
f µ
+ 6 ln 26
55 ! , 5 g2
1(µ)
3 g2
2(µ)
2 g2
3(µ) =
1 8π2 12 ln M2
XMΣ75
µ3
+ 54 ln 5
4 ! .
MHC = 6.4 × 1015 GeV
(M2
XMΣ24)1/3 = 1.5 × 1016 GeV
Minimal SU(5)
(M2
XMΣ75)1/3 = 5.4 × 1015 GeV
MHC MHC MH0
f