"CP-violating decay K0L -> pi0 nu nubar"
by L. Littenberg(BNL),
Phys. Rev. D39 (1989), 3322
[pdf file]:
the first paper on pi0nunubar.
supplementary documents:
"Measurement of the Decay Rate of K_2^0 -> pi^0 pi^0"
by J.W. Cronin et al.,
Phys.Rev.Lett. 18 (1967) 25 [ pdf file ]:
the experiment cited in Reference [18].
Please remind the drawings for Figs. 2 and 3 should be interchanged
(the captions are correct); see the ERRATUM.
"Particle Production by 2.9-BeV Protons Incident on Beryllium and Platinum"
by P.A.Piroue and A.J.S.Smith (Princeton),
Phys.Rev 148 (1966) 1315 [ pdf file ]:
the beam survey program at the 2.9-GeV Princeton-Pennsylvania Accelerator (PPA).
Exercises
Explain, in a few sentences,
why the amplitude of the KL->pi0 nu nubar decay is proportional to
Im(V_td), i.e. CP violation, while the amplitude of
the K+->pi+ nu nubar decay is proportional to |V_td|.
Explain why the ratio of the KL and K+ lifetimes appear
in the last two equations in page 3322.
Show that "the photon spectrum from K0L->2pi0 is a flat box
extending from 19 to 229 MeV" (in page 3323)
with the kinematics of the pi0 -> gamma gamma decay.
Hints: See Problem 1.4 of "Introduction to High Energy Physics", 4th edition,
by D.H.Perkins.
In page 3323, with 156 events observed in the interval 180-225 MeV ("signal" region),
181 events were used as an upper limit.
Explain how to calculate the upper limit (based on the Poisson distribution) exactly, and approximately.
"Search for the decay KL -> pi0 nu nubar"
by G.E. Graham et al.(FNAL-E731 collaboration),
Phys. Lett B295 (1992) 169-173
[pdf file]:
the first experimental search for the decay, with pi0->eegamma, <2.2E-4.
Exercises
Show that the pi0 nu nubar system is an even-CP state.
Hints: See Section 1.1 of the E391a proposal (KEK Internal 96-13).
Write down schematic Feynman-diagrams of KL->e+e-gamma and KL->e+e-gammagamma decays,
respectively, and estimate their branching ratios from the branching ratio of KL->gammagamma.
Explain why the branching ratio of KL->e+e- is much smaller than that of KL->e+e-gamma.
Explain why "each drift chamber consisted of __two__ X planes and __two__ Y planes" (in page 170).
What new detector-subsystem(s) should be added to the E731 detector
if we want to achieve better e+-/pi+- separation ?
Explain why "the electron-positron pair (from pi0 Dalitz decay) usually has a
very small opening angle" (in page 171).
Consider a set of better trigger conditions for KL->pi0nunubar and KL->e+e-gamma than the case of E731.
Calculate the probability that 350GeV Lambda hyperon survives at 120m from the production target.
Guess the background level expected in the signal region of Fig.3.
"Limit on the Branching Ratio of KL -> pi0 nu nubar"
by M. Weaver et al.(FNAL-E799 collaboration),
Phys. Rev. Lett. 72 (1994), 3758
[pdf file]:
with pi0->eegamma, <5.8E-5.
supplementary documents:
"Incorporating systematic uncertainties into an upper limit"
by R.D. Cousins (UCLA) and V.L. Highland (Temple UnivJ,
Nucl. Instr. and Meth. A320 (1992) 331-335:
the paper in Reference [11].
The paper discusses how to incorporate the uncertainty in the experimental sensitivity
into the calculation of an upper confidence limit on a branching ratio or similar quantity.
"A Calculator for Confidence Intervals"
by R. Barlow (Manchester Univ),
hep-ex/0203002.
A calculator program to give confidence intervals on branching ratios for rare decay modes.
Exercises
Write down a schematic Feynman-diagram of CP conserving KL->pi0e+e-.
Explain how the information on the indirect CP violating part and CP conserving part of KL->pi0e+e-
can be obtained from other experimental measurements.
Show the changes from the E731 to E799-I detectors and in their trigger conditions.
List and compare the main background sources to KL->pi0nunubar in the E731 and E799-I analyses.
In FIG.1, the plot of eegamma mass from Ke3 decays with radiative or accidental photons
for data (histograms) is reproduced by Monte Carlo simulation (crosses).
How can "accidental photons" be produced in the Monte Carlo ?
"With the E799 detector 96% of electrons satisfied these requirements, compared to 2.5% of pions from Ke3 decays"
(in page 3760) suggests that the pi+ rejection (or pi/e separation) in the E799-I detector was around 40.
In the E731 analysis, pi/e separation was about 100. Why was the pi/e separation in E777-I not-so-good,
even after the detector was upgraded ?
All the information from this experiment is 1) the single event sensitivity (SES): 2.48+-0.16+-0.19 E-5,
2) the expected background events (BGD): 0.6+-0.2, and
3) the number of observed event (SIG): zero.
Getting an upper limit on the branching ratio
is a matter of statistical analysis of these numbers.
Calculate the 90% C.L. upper limits by:
ignoring both the errors in the SES and the number of BGD,
taking care of the correction due to the uncertainty in the SES and ignoring the number of BGD
(Hints: See supplementary document 1),
ignoring the errors in the SES and taking care of the number of BGD
(Hints: Use the calculator in supplementary document 2),
ignoring the errors in the SES and taking care of the number of BGD with its error, and
ignoring the errors in the SES and taking care of the number of BGD with its error
in the case that the number of SIG is one,
respectively.
In the conclusion, "Of particular importance are hermetic photon veto systems and better e/pi separation".
Consider how the E799-I detector should be upgraded, and how the trigger rate, which was dominated by Ke3 decays
in E799-I, can be reduced.
"Search for the decay KL -> pi0 nu nubar"
by J. Adams et al.(FNAL-KTeV Collboration),
Phys. Lett. B447 (1999), 240
[pdf file]:
with pi0->gamma gamma for the first time, <1.6E-6.
supplementary documents:
"The KTeV hardware cluster counter"
by C. Bown et al.,
Nucl. Instr. and Meth. A369 (1996) 248:
the paper in Reference [10].
Exercises
What Single-Event-Sensitivity can we reach if E391s performs a "one-day special run" ?
Check the thickness of a vacuum window, the expected vacuum, and the relative ratio of neutrons and KL's
in E391a.
Check the proton intensity per pulse and the targetting angle of the proton beam in KTeV and in E391a, respectively.
What is the main purpose of the Photon Veto Sets in the KTeV detector in the epsilon'/epsion mode ?
Why was the TRD detector in KTeV unused in the one-day special run ?
Why are the energy threshold levels in Photon Veto subsystems different each other ?
Where are the hyperon decay events in Fig,2 ?
Check the lifetime, c*tau and main decay modes of the Lambda and Xi hyperons, respectively.
List up the offline cuts used in this analysis. These cuts will be tested at first in the E391a analysis.
Explain how the 90% C.L. upper limit is calculated
by "conservatively assuming that the last remaining event is signal"(p.245).
What is the conclsion of this paper on the improvement of the sensitivity in the future experiments ?
"Search for the decay KL -> pi0 nu nubar using pi0->e+e-gamma"
by A. Alavi-Harati et al.(FNAL-KteV collaboration),
Phys. Rev. D61 (2000), 072006
[pdf file]:
the best upper limit with pi0->eegamma, <5.9E-7.
supplementary documents:
"Use of the KL->3pi0 decay as a tagged photon source
to measure material thickness in a neutral kaon beam"
by E. D. Zimmerman (Chicago),
Nucl. Instr. and Meth. A426 (1999) 229
[pdf file]:
the paper in Reference [14]. This technique (with the spectrometer magnet off)
should also be used in E391a.
Exercises
Why were the events with three __or four__ clusters in the calorimeter accepted in the trigger ?
What is the merit of using the TRD pulse height information in the trigger ?
Explain the "blind analysis" in this analysis.
Show the figure-of-merits of the E/p cut, the cut to identify pions formed from the 8 TRS's,
the photon veto (PV) cuts to Kpi3 and the PV cuts to Kpi2, respectively.
Calculate the probabilities of hyperons surviving in the beamline of KTeV and E391a,
respectively.
What is the main background source in this analysis ?
and what would be the most serious background when the sensitivity is improved
with this detector ?
Why is the Kpi2 backround not-so-serious in this technique ?
What determines the systematic uncertainty of the single-event sensitivity ?
Which KL decay mode would be used in the normalization of E391a analysis ?
"Collider Experiment: Strings, Branes and Extra Dimensions"
by Maria Spiropulu (EFI-Chicago) at TASI 2001,
hep-ex/0305019
[2003 - 7/03,7/10,8/07,8/21,9/04,9/18].
supplementary documents:
"Tevatron Physics"
by John Womersley (FNAL) at TASI 2002,
hep-ex/0301007.
Another TASI lecture given by an experimentalist to theorists.
In the Appendix: Student Exercise for TASI 2002,
you can experience an analysis in hadron collider experiments
(which is quite different from the analysis in rare kaon-decay experiments !),
by using the public interface to D0 Run 1 data called "Quaero".
the ABC's of accelerators:
"Chapter 2 Accelerators"
of "Subatomic Physics (Second Edition)"
by H.Frauenfelder and E.M.Henley, 1991.
"Chapter 16 High-Energy Physics: The Gadgets"
of "Modern Physics from alpha to Z^0" by J.W.Rohlf, 1994.
"Experimental Aspects of the Standard Model: A Short Course for Theorists"
by Persis Drell (Cornell) at TASI 1996,
hep-ex/9701001.
"Future Accelerators (?)"
by John Womersley (FNAL),
hep-ex/0308028.
"Search for Gluinos and Scalar Quarks in $p\bar{p}$ Collisions at $\sqrt{s}=1.8$ TeV
using the Missing Energy plus Multijets Signature"
by the CDF Collaboration,
hep-ex/0106001,
Phys.Rev.Lett. 88 (2002) 041801 [ pdf file ]:
the paper cited as Reference [17].
"Search for Large Extra Dimensions in the Monojet + Missing ET Channel at D0"
by the D0 Collaboration,
hep-ex/0302014,
Phys.Rev.Lett. 90 (2003) 251802 [ pdf file ]:
the D0 paper cited in Reference [47].
"Limits on Extra Dimensions and New Particle Production
in the Exclusive Photon and Missing Energy Signature in p pbar Collisions at sqrt(s) =
1.8 TeV"
by the CDF Collaboration,
hep-ex/0205057,
Phys.Rev.Lett. 89 (2002) 281801 [ pdf file ]:
the CDF paper cited in Reference [47].
"Extra Dimensions and More"
by Greg Landsberg (Brown),
hep-ex/0105039:
a summary of LEP results on graviton emission, cited in Reference [47].
"Large Extra Dimensions in Rare Decays"
by Johan Bijnens and Martin Maul (Lund),
hep-ph/0006042:
Some general arguments why in Kaon and Pion decays signals of the large extra dimensions will be small.
"Neutrinos, Grand Unification and Leptogenesis"
by W. Buchmueller (DESY),
hep-ph/0204288
[2003 - 5/15,5/22,5/29,6/05,6/12,6/19].
There are serious mistakes in pages 26-28 (SNO's results on Solar neutrinos).
See my note.
supplementary documents:
"Neutrino Masses and Mixing: Evidence and Implications"
by M.C. Gonzalez-Garcia (CERN/Valencia/SUNY) and Y. Nir (Weizmann),
hep-ph/0202058.
This is a pedagogical (and thicker) review on the subject.
"The Radiations Emitted from Artificially Produced Radioactive Substances. I.
The Upper Limits and Shapes of the beta-Ray Spectra from Several Elements"
by F.N.D. Kurie et al.,
Phys. Rev. 49, 368-381 (1936)
[ pdf file ].
The original "Kurie plot" appears in this publication.
"No 17 keV neutrino: Admixture < 0.073% (95% C.L.)"
by T. Ohshima et al.,
Phys. Rev. D47, 4840-4856 (1993)
[ pdf file ].
This paper killed the "17 keV Heavy Neutrino" in the early 90's. You might be interested in the author list
of this paper.
"Evidence for Neutrinoless Double Beta Decay"
by H.V. Klapdor-Kleingrothaus et al.,
hep-ph/0201231
(and a debate on the paper:
hep-ex/0202018 and
hep-ph/0205228).
This result is NOT regarded as the conclusive evidence for
neutrinoless double beta decay.
"When can you have particle oscillations?"
by A, J. Weinstein (SLAC),
in T.Ferbel(ed.), Techniques and Concepts of High Energy Physics X, 1999, 291-293.
An answer to the question: "why we consider the phenomenon of neutrino oscillation,
yet never consider the possibility of oscillations between the electron, muon and tau leptons
themselves" is given in this manuscript, but remind this problem is still in debate.
"Neutrino Mass, Mixing, and Flavor Change"
by B. Kayser (FNAL),
hep-ph/0211134.
Theoretical basics of these concepts
are explained carefully.
The Neutrino Oscillation Industry
An index of experiments and related subjects having to do with neutrino mass and
oscillations. You can find links to all of the famous neutrino experiments,
including:
"Introduction to Heavy Meson Decays and CP Asymmetries"
by Zoltan Ligeti (LBNL),
hep-ph/0302031
[2003 - 3/20, 4/03, 4/10, 4/17, 5/08].
We read only the Section 1 "Introduction to Flavor Physics: Standard Model Review,
Mixing and CP Violation in Neutral Mesons" of this.
supplementary documents:
"CP Violation - A New Era"
by Y. Nir (Weizmann),
hep-ph/0109090.
This is a pedagogical review on the theories.
"Mass and Flavor Mixing Schemes of Quarks and Leptons"
by H. Fritzsch and Z-z Xing (Muenchen),
hep-ph/9912358.
See Section 3 (and 3.5) for different parametrizations of CKM matrix.
"Evidence for the 2 pi Decay of the K^0_2 Meson"
by J. H. Christenson, J. W. Cronin, V. L. Fitch, and R. Turlay (Princeton),
PRL 13, 138 (1964)
[ pdf file ].
The history of rare kaon-decay physics began in 1964
with the unexpected evidence for the CP violating KL -> pi+pi- decay
at the sensitivity of E-3 by this famous "Fitch-Cronin" experiment at BNL-AGS.
All the students of particle physics MUST read this paper.
See also their 1981 Novel-Prize lectures:
"Invariant Principles and Elementary Particles"
by J. J. Sakurai, Princeton University Press, 1964.
This monograph is well known as one of the masterpieces of Particle Physics
and,
though it was
written before the the CP violating was discovered,
this book is still very useful and highly recommended.
As far as I know,
this is the only one explaining
why we may regard electron and positron (and pi+ and pi-) as
"identical" particles (See 5.2).
"The CKM Matrix and the Unitarity Triangle",
Proceedings of the First Workshop on the CKM Unitarity Triangle, CERN 13-16 February 2002,
hep-ph/0304132.
This report (in 330 pages!),
joined by most of the expert-theorists in the quark-flavor physics,
will be a major reference of the field in the next few years.
We should at least study the pages 309-316 on K -> pi nu nu decays (by G.Isidori and D.E.Jaffe).
"Rare Kaon and Pion Decays"
by Laurence Littenberg (BNL),
hep-ex/0212005
[2003 - 2/20, 27, 3/13].
supplementary documents:
"The Sensitivity Frontier: Kaon Physics in the Era of Precision B-Physics"
by Robert S. Tschirhart (FNAL),
Proceeidngs of the SLAC Summer Institute 2002.
This is another lecture on Kaon Phyiscs in 2002 summer schools.
back to the top updated on 2005-October-13(Thu) by Takeshi K. Komatsubara (KEK-IPNS)