Neutrinos Ramon Miquel LBNL Exciting period About 75

Neutrinos Ramon Miquel (LBNL) • Exciting period. About 75 new measurements. Further confirmation of large mixing between neutrinos. • Many changes in previous year 2000 2002 • No big changes in 2004 – Turned mixing mini-review into big review on mass and mixing. • Another batch of changes foreseen for 2006. PDG '04 Meeting

Large Group of People Involved Maury Goodman Don Groom Encoding of accelerator neutrino papers “Understanding Two-Flavor Oscillation Parameters and Limits” Boris Kayser “Neutrino Mass, Mixing, and Flavor Change” (new review; was a mini-review) Dean Karlen “Number of Light Neutrinos” Ramon Miquel Overseer Hitoshi Murayama Plot with current oscillation parameters Kenzo Nakamura Encoding of extraterrestrial neutrino papers “Solar Neutrinos” Keith Olive Encoding of Astrophysical papers Andreas Piepke Encoding of Nuclear Physics papers & “Electron, Muon and Tau Neutrino Listings” Petr Vogel “Limits from Neutrinoless Double Beta Decay” + consultants, referees, verifiers… PDG '04 Meeting

Implications of Large Mixing • One experiment measuring the “neutrino” mass with neutrinos produced with charged lepton l is actually sensitive to • Since off-diagonal terms in are large, one cannot pretend to be measuring any particular • Furthermore, kinematics, for instance, can make the measurement insensitive to one of the mass eigenstates, further complicating the interpretation PDG '04 Meeting

Current Structure of Summary Tables • Old ne, nm, nt headers are kept because most experiments are performed with beams/samples of weak eigenstates. • However, there are caveats in the tables and an introductory mini-review by Vogel and Piepke. 2/26/2021 PDG '04 Meeting 4

Current Structure of Particle Listings (1) i. Minireview on neutrino masses ii. Listings of ne, nm, nt with the appropriate caveats iii. Listings of number of neutrino types (with minireview) and sum of masses iv. Listings of double-b decay (with minireview) v. Minireview: Understanding 2 -flavor oscillation limits (continued) PDG '04 Meeting

Current Structure of Particle Listings (2) (continued) vi. Listings of neutrino mixing: A. Accelerator neutrino experiments B. Reactor neutrino experiments C. Atmospheric neutrino experiments D. Solar neutrino experiments (with minireview) vii. Listings of searches for heavy neutral leptons (exotics) PDG '04 Meeting

Reviews • Greatly expanded mass and mixing review by Kayser: – Upgraded from mini-review to full review – Added two-flavor oscillation plot – Added discussion on Majorana masses and 0 nbb decay • Revised neutrino masses review by Vogel and Piepke. • Revised neutrinoless double-beta decay by Vogel and Piepke. • Revised solar neutrino review by Nakamura. PDG '04 Meeting

New Figure by Hitoshi Murayama • Combines all two-flavor oscillation data in one figure. • Solar, atmospheric, reactor and accelerator results available at a glance. • It is now part of Boris Kayser’s review on neutrino mass and mixing. 2/26/2021 PDG '04 ’ 04 Meeting 8

Challenges • Sections on ne, nm, nt still seem to generate confusion about mass eigenstates vs. flavor eigenstates. • Mixing section is long and potentially confusing, with many old and now maybe irrelevant limits mixed with the current, exciting mixing measurements. • Classification of mixing by technique puts related measurements (SNO & Kam. LAND, Super. K & K 2 K) several pages apart. Decided to have small workshop to discuss possible improvements in neutrino listings (LBL, 11/12/04) PDG '04 Meeting

Summary of Workshop on 11/12/04 (I) • Mixing – Introduce new “nodes” with measurements of q 12, q 23, q 13, Dm 212, Dm 223 in the 3 -neutrino scenario, including mini-review explaining how it is done, assumptions, etc. – Remove Don’s two-flavor mini-review which focuses on understanding limits. – Keep solar fluxes, atmospheric flux ratios, reactor flux ratios. Add accelerator flux ratios. – Remove obsolete oscillation limits in Dm 2 regions we now know are irrelevant. – Keep LSND-related limits from nm ↔ ne oscillation searches. PDG '04 Meeting

Summary of Workshop on 11/12/04 (II) (Karsten Heeger, LBNL) PDG '04 Meeting

Summary of Workshop on 11/12/04 (III) • Sections on ne, nm, nt: – Eliminate “particles” called ne, nm, nt. – Rename nodes with masses, etc. to reflect what is really being measured. Example: . – Same thing for lifetime to mass ratio, magnetic moment, electric dipole moment, etc. – In some cases (astrophysics), limits apply to all flavors: only one node needed. – Remove many obsolete results, mostly in mass ranges that are now irrelevant. – Add node for n 2 lifetime to mass ratio (from limits to Majoronemission decays of solar neutrinos). 2/26/2021 PDG '04 Meeting 12

Summary of Workshop on 11/12/04 (IV) • This was the outcome to the Workshop on Friday 11/12/04. We will send this proposal around to the wider neutrino PDG group for comments. • Plan is to come up with a final design by early 2005, so that it can be applied to the 2006 book, maybe to the 2005 web update. Freedman, Goodman, Groom, Miquel, Nakamura, Olive, Vogel, Gonzalez-Garcia, Kayser, Lesko, Lisi, Murayama, Piepke 2/26/2021 PDG '04 Meeting 13

Conclusions • Neutrino physics continues to be very exciting. • RPP is adapting well to the changes in our understanding of neutrino physics. • Great reviews help the reader follow this rather complicated subject. • Several changes in the listings will be applied for 2006. Final decision to be taken early 2005. • Future changes may depend on the outcome of Mini. BOONE. PDG '04 Meeting