University of Manchester QUARK FLAVOUR PHYSICS Chris Parkes University of Manchester Part VI Concluding Remarks Other flavour physics / CPV searches Overall Constraints on CKM Triangle

Other areas of measurements made by quark flavour experiments not discussed yet: Spectroscopy Spectroscopy: Z(4430)-

Exotic States Mesons: quark, anti-quark Baryons: 3 quarks An area of quark flavour physics we haven’t discussed is searching for new meson states Mesons: quark, anti-quark Baryons: 3 quarks 50 year history of searching for ‘exotic’ states For example:

Z(4430)- : Exotic State Belle discovered X(3872 MeV) in 2014 LHCb, 2014, arXiv:1404.1903 Belle discovered X(3872 MeV) in 2014 didn’t match any predicted mass state for a charm meson Subsequently a number of other states that don’t “fit” have been found Z(4430)- is a charged state, given its mass its minimal quark content i.e. a four-quark state Possible exotic explanations include: tetra-quark : di-quark di-anti-quark; or charmonium-’molecule’ mixture.

Pentaquark States Invariant mass calculation using with measured momenta known J/Ψ, p, K masses E, p, conservation Clean selection – low background Λb quark content (udb) Study two-body mass combinations Quark content J/Ψ (cc), p (uud)

Full analysis – with all known contributions to Dalitz plots included in model – shows two new states needed Pentaquarks !

Other type of measurements sensitive to CP violation in quarks but not made by accelerator-based quark flavour experiments Dipole Moments

So another way of finding CP Violation Dipole moment reverses under P Spin reverses under T So another way of finding CP Violation (and another good LHCb PhD thesis topic…)

Neutron Electric Dipole Moments Experiment at IIL, Grenoble from Sussex, RAL et al. Initially rom temp, now cryo. expt Neutron Electric Dipole Moments Spin precession frequency of ultracold neutrons in a weak magnetic field. 1.Take neutrons from reactor at ILL 2. Slow them down and store (100s) 3. Apply weak magnetic field neutron spin precesses in magnetic field due to magnetic moment of neutron 4. strong electric field is applied also If an EDM this will interact and spin precession will speed up or slow down 5. Measure precession with NMR

Triangle – Overall Fits CKM Measuring Parameters Triangle – Overall Fits

CKM metrology How are the CKM parameters magnitudes (not phases) measured? Magnitudes are typically determined from (ratios of) decay rates E.g. compare decay rates of neutron and muon decays (  Vud2) |Vud| : nuclear b-decay ~ (0.97380.0003) |Vus| : semileptonic kaon decays ~ (0.2260.002)

Remember unitarity constraints – e.g. so can constrain for further generations of quarks from magnitudes only

CKM metrology – constraints in the (r, h) plane Taken from the UTfit homepage: http://www.utfit.org Kaons CPV B CPV B magnitudes only B CPV B Mixing B CPV

CKM metrology and unitarity triangle fit CKM Mechanism in SM proven to work Now a good way to discover new physics Over constraining triangle and compatibility of angle measurements

CKM metrology and UnitarityTriangle: Current Status There is still compatibility with the Standard Model ! Constraints from many CKM matrix complementary and independent measurements

Concluding remarks CP violation is a fundamental broken symmetry Needed for matter anti-matter asymmetry It can be incorporated in the Standard Model, but seems like an “add-on”  SM cannot be the final answer nowhere near enough CP Violation in quark sector Study of CP violation involves precise measurements of the CKM matrix Present measurements allow to over-constrain the CKM triangles and look for inconsistencies Inconsistencies would be a sign for New Physics And rare decays also an important method for searching for New Physics A lot of hope and expectation for the (near) future experimental results!