FUTURE PROSPECTS OF FLAVOR PHYSICS IMPACT OF NEUTRINO PHYSICS TO THEORY THREE MAIN EXPERIMENTAL RESULTS (HIGGS, NEUTRINOS AND CKM) INDICATE SUSY GUT NAGOYA UNIV. KMI NOBUHIRO MAEKAWA 1, Message to Nishikawa-san 2, Main Experimental results of particle physics in 21 st century 3, Higgs particle (LHC) 4, SUSY GUT 5, Neutrino physics 6, CKM matrix 7, Nucleon decay 8, Summary Koichiro Nishikawa Memorial Symposium 2019.9.27
MESSAGE TO NISHIKAWA-SAN 5-6 years overlap in Kyoto univ. but I was just an assistant in theory group… • I was asked to pass the words to Nishikawa-san by Mr.&Mrs. Kubo. • They are close family friends of Nishikawa-san. I will present their message here.
MESSAGE TO NISHIKAWA-SAN Dear Koichiro san, 34 years ago our small children brought our famlies together in Stony Brook, Long Island. The trust and sympathy were there from the beginning. We enjoyed together eating, drinking, picnics, etc. and forgot for a while our insecure future. In the following decades we met each other time to time. Each time we met, you left behind remarks that brought us to think about for a long time. After you returned to Japan, you had have to overcome numerous problems to realise your ideas in particle physics, and finally you achieved extraordinary successes. Once again we would like to express our respect. We cherish the fond memories of you and your family. Rest in peace. Annette and Jisuke Kubo in München
SUMMARY OF MY TALK Impact of neutrino physics is huge. A SUSY SO(10) (or E6) GUT is indicated by neutrino experiments. It was confirmed by CKM measurement. Neutrino masses and mixings are important to understand the signature of SU(5) GUT. • The quark and lepton masses and mixings can be an experimental signature for unification of • matters in SU(5) GUT. A simple assumption explains hierarchical structures of quark and lepton masses and mixings • in SU(5) GUT. SO(10) GUT is more attractive because one generation quark and leptons can be unified into a • * + + ) * + 0) + 1(1 ) * ) + - * ) ), that leads to unrealistic SO(10) single multiplet ( 16 = 10(& + ( ) 5(/ ) GUT relation 2 3 = 2 4 = 2 5 = 2 6 7 A change in SO(10) realizes the simple assumption in SU(5) so that realistic Yukawa matrices • can be obtained. 8 59 ∼ sin > ? = @ , which is confirmed in 2012, is a remnant of matter unification of SO(10), • and can be a signature of the SO(10) GUT with the above change. 3A ∼ @ B is a remnant of unrealistic SO(10) relation 2 8 3 = 2 4 and can be a signature of the • SO(10) GUT with the above change. Nucleon decay is interesting. •
BUT LHC HAS NO SIGNATURE FOR SUSY. Let us look back at “before LHC starts”. • 180 GeV<Higgs mass → strong coupling (Technicolor etc) 130 GeV<Higgs mass < 180 GeV → standard model Higgs mass < 130 GeV → SUSY LHC found that the Higgs mass is 125 GeV, that indicates SUSY! 125 GeV Higgs implies larger SUSY breaking scale ( " #$#% > 1 TeV) . • No SUSY signature in LHC is not surprising. (It is a “prediction”.) SUSY becomes the standard model in the low energy if SUSY breaking scale is • large. (This is not the case in technicolor theory.) Precision measurements and/or constraints from cosmology may be more • important in near future.
BRIEF REVIEW OF GRAND UNIFIED THEORY (GUT) Two unifications Unification of forces (Gauge interactions) • !" 3 $ ×!" 2 ' ×" 1 ) ⊂ !"(5) ⊂ !.(10) Unification of matters • 4 + 5 3 4 + 6 4 + 8 + 1 9 3 4 10 0 + 2 3 5 7 3 = 16 Experimental supports for both unifications ⟹ GUT is promising •
BRIEF REVIEW OF GRAND UNIFIED THEORY Unification of gauge interactions : Prediction ! " = ! $ = ! % • Standard model(SM) SUSY SM This is quantitative evidence for unification of forces Unification of matters • Hierarchical structures of quark and lepton masses and mixings can be explained by a simple assumption in SU(5) GUT. (Without neutrino observations, we would not come to this conclusion.) “10 fields induce stronger hierarchies in Yukawa couplings than & 5 fields �
MASSES & MIXINGS AND GUT � � � ����������� �� �� ���� �� �������������� �� �������� �� ��� ��� u, c, t Strongest CKM small mixings Neutrinos Weakest e, μ � τ Middle MNS large mixings d, s, b Middle These can be naturally realized in SU(5) GUT!!
IMPACT OF NEUTRINO PHYSICS SU(5) GUT IS INDICATED “10 fields induce stronger hierarchies in Yukawa couplings than ! • 5 fields � • Up quarks have the strongest hierarchy. Neutrinos have the weakest. Down quarks and charged leptons have middle hierarchies. Neutrino mixings are larger than quark mixings. • %& Left index: LH fields, Right index:RH fields %& , # %& , # • # $ ) ( %& Both indeces: LH fields : ; • F + G E F + I, F , ! F 10 = B + D E 5 = H E 1 = J E • ( (10 , ! ) (! 5, 10 ), : ; ( ! 5 , ! # $ ( 10 , 10 ), # 5 ), # 5 ) • • Stronger hierarchy results in smaller mixings. 5 L , ! ! 5 M , ! 10 L , 10 M , 10 N → P N , P M , 1 , 5 N → P N , P M.R , P M P ∼ 0.22 • P U P R P N P U P R.R P R P U P R.R P R W ∼ # $ ∼ , # ( ∼ # , : ; ∝ P R P V P M P R P V.R P V P R.R P R P V.R ) P N P M P N P M.R P M P R P V.R P V 1 P N P ].R 1 P 1 P Y Z[\ ∼ Y L] ∼ P M , Y \^_ ∼ Y R ∼ P ].R P ].R P 1 1 ` P N P M P ].R 1 P 1
SO(10) GUT IS SUGGESTED BY NEUTRINO PHYSICS N.M.01 * + + ) * + 0) + 1(1 ) * ) + - * ) SO(10) is more attractive. 16 = 10(& + ( ) 5(/ ) • 8 5 67 ∼ 0.05 eV, 2 3 7 ∼ 100 GeV ⇒ = 3 : ∼ 10 >? GeV ∼ Λ ABC Seasaw mechanism: 2 3 ∼ 9 6: This suggests that right-handed neutrinos can obtain masses only after breaking unified group. SO(10) or E6 GUT. Unrealistic Yukawa relations D E = D F = D G = D D HI 16 H 16 I 10 J 16 > , 16 L , 16 M → • 3 7 (O M , O L , 1) Realization of the assumption “10 induce stronger hierarchies in Yukawa couplings than - 5 � Easiest solution � 10 C = 5 C + - 5 C One of four - 5 fields is superheavy after breaking PQ 10 → PR(5) The other three become matters. D H 16 H 16 S 10 C + = C 10 C 10 C 16 S PQ 10 → PR(5) - M is larger. Typical matter is - 5 > , - 5 C , - 5 L . If - 5 C + O L.T - 5 M becomes heavy because D 5 M , 5 UM → O M , O L.T , O L is realized. 5 U> , - - 5 UL , - 10 > , 10 L , 10 M → O M , O L , 1 , Important evidence V SW9 >L ∼ V 9XY >M ∼ O : is discovered in 2012. E6 GUT: 27 = 16 + 10 + 1 The above structure is naturally realized. •
SO(10) GUT IS SUGGESTED BY UNITARITY TRIANGLE. Kurosawa-N.M. "# ∼ % & ! (not % ( ) % & ! • -% ( (/ − 12) 1 % ! )*+ ∼ -% 4 −% 1 -% ( (1 − / − 12) −-% 4 1 Ishiduki-Kim-N.M.-Sakurai 09 The prediction of 5 6 ×89 2 ; ×9 1 < ×=> Necessary condition 78 < = 45 < ∝ E FGH This direction plays an important role in solving the doublet-triplet splitting problem Today’s claim "# ∼ % & can be a prediction of the 8W 10 GUT ! discussed previously. "# ∼ % & is an evidence of So, we want to say that ! SO(10) or E6 GUT
NUCLEON DECAY IS INTERESTING BECAUSE WE HAVE UNDERSTOOD YUKAWA STRUCTURE. That is important in predicting nucleon decay via superheavy gauge boson. • 5 . ( / ∗ ) , 10 # , 10 % , 10 & → ( & , ( % , 1 , 10(*) 5 # , , , 5 % , , 5 & → ( & , ( %.2 , ( % ( & 1 ( 6 , 3 #4 ∼ 3 3, 2 9 3 ( % ( 1 ; #4 2 : ( & ( % 1 , 10 . (< = >∗ ) > ) 5(? = ( 4.2 1 ( 3 2 ∼ ( 4.2 ( 4.2 1 ; ( 4.2 ( 1 It is like CKM matrix in weak interaction. • In SO(10) we have an additional superheavy gauge boson which induces nucleon decay. • In E6, we have an additional superheavy gauge boson which induces nucleon decay. • We may identify the unified group by measuring branching ratios of nucleon decay. •
N.M.-Muramatsu 1307,1601 ! "#(%) = ! "(()*) = 2! , - By Y. Muramatsu Unfortunately, . → 0 * 1 is more difficult to be observed.
WHAT HAPPENS IF O(1) COEFFICIENTS ARE FIXED? IT MAY BE POSSIBLE IN SO(10). More sharp predictions of nucleon decay become possible. • If SUSY breaking parameters are fixed, various FCNC and CP violating processes • can be predicted.
SUMMARY OF MY TALK Impact of neutrino physics is huge. SUSY SO(10) (or E6) GUT is suggested by neutrino experiments. It was confirmed by CKM measurement. Neutrino masses and mixings are important to understand the signature of SU(5) GUT. • The quark and lepton masses and mixings can be an experimental signature for unification of • matters in SU(5) GUT. A simple assumption explains hierarchical structure of quark and lepton masses and mixings in • SU(5) GUT. SO(10) GUT is more attractive because one generation quark and leptons can be unified into a • * + + ) * + 0) + 1(1 ) * ) + - * ) ), that leads to unrealistic SO(10) single multiplet ( 16 = 10(& + ( ) 5(/ ) GUT relation 2 3 = 2 4 = 2 5 = 2 6 7 A change in SO(10) realizes the simple assumption in SU(5) so that realistic Yukawa matrices • can be obtained. 8 59 ∼ sin > ? = @ , which is confirmed in 2012, is a remnant of matter unification of SO(10), • and can be a signature of the SO(10) GUT with the above change. 3A ∼ @ B is a remnant of unrealistic SO(10) relation 2 8 3 = 2 4 and can be a signature of the • SO(10) GUT with the above change. Nucleon decay is interesting. •
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