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Fig. 7.— E691 Detector: vertex detector region(left); forward spectrometer (right). From ref.|61) Fig. 5. — Ge-Si active target of CERN NA1 experiment (left). A D+ D7 event and corresponding pulse height pattern in target (right). From Ref. [63].

Figure 7 — E691 Detector: vertex detector region(left); forward spectrometer (right). From ref.|61) Fig. 5. — Ge-Si active target of CERN NA1 experiment (left). A D+ D7 event and corresponding pulse height pattern in target (right). From Ref. [63].

Related Figures (51)

Fig. 3. — First charm candidate event in nuclear emulsions [8]. Figure from Ref. [12]
Fig. 3. — First charm candidate event in nuclear emulsions [8]. Figure from Ref. [12]
, 4. MARK2 Detector: exploded and beam view (From [B9])
, 4. MARK2 Detector: exploded and beam view (From [B9])
‘ig. 8. - ARGUS Detector (elevation view from ref.[68})
‘ig. 8. - ARGUS Detector (elevation view from ref.[68})
TABLE I. — Charm in today’s experiments. Sample column shows number of reconstructed events. AM is the typical mass resolution, At is the typical proper time resolution.
TABLE I. — Charm in today’s experiments. Sample column shows number of reconstructed events. AM is the typical mass resolution, At is the typical proper time resolution.
The kinetic mass (so-called since it enters in the kinetic energy of the heavy quark) on the other hand is regular in the infrared regime with [86] [85] [87] (°) MS stands for ‘modified minimal subtraction scheme’.
The kinetic mass (so-called since it enters in the kinetic energy of the heavy quark) on the other hand is regular in the infrared regime with [86] [85] [87] (°) MS stands for ‘modified minimal subtraction scheme’.
N+ denotes the active flavours. Next-to-leading log corrections are sizeable at the charm scale. They cannot be expressed in a compact analytical way; numerically one finds when including these contributions: The coefficients c1,2 can be expressed as follows at leading log level:
N+ denotes the active flavours. Next-to-leading log corrections are sizeable at the charm scale. They cannot be expressed in a compact analytical way; numerically one finds when including these contributions: The coefficients c1,2 can be expressed as follows at leading log level:
Fig. 10.— Diagrams for charm production: Hadroproduction (a,b); electron-proton production (c); photoproduction point like photon (d), resolved photon (e); neutrino (f); eFe™ (g).
Fig. 10.— Diagrams for charm production: Hadroproduction (a,b); electron-proton production (c); photoproduction point like photon (d), resolved photon (e); neutrino (f); eFe™ (g).
‘ig. 11. — CDF results on cross section for J/~w (a), w’ (b), and polarization (c,d). Data from [19] [120], theoretical predictions from [121] [122].
‘ig. 11. — CDF results on cross section for J/~w (a), w’ (b), and polarization (c,d). Data from [19] [120], theoretical predictions from [121] [122].
Fig. 12. — Colour-singlet and colour-octet diagrams for hadroproduction (left) and ete~ pro- duction (right) of charmonium; photons and gluons are denoted by wave and curly lines, respec- tively.
Fig. 12. — Colour-singlet and colour-octet diagrams for hadroproduction (left) and ete~ pro- duction (right) of charmonium; photons and gluons are denoted by wave and curly lines, respec- tively.
Fig. 14. — Chart of ground state charmed meson and baryon multiplets {131)
Fig. 14. — Chart of ground state charmed meson and baryon multiplets {131)
Fig. 15. — Masses and transitions predicted for the excited D meson states (pre-Spring 2008).
Fig. 15. — Masses and transitions predicted for the excited D meson states (pre-Spring 2008).
TABLE III.— Winter ’02/’03 status of (L=1, n=1) and (L=0, n=2) cq and cS mesons (MeV). Statistical and systematical errors added in quadrature. Experimental results not included in PDG are from BELLE [199, CLEO [i96J, DELPHI [200], FOCUS (207) (202). Theory predictions from (203). 6°3.3. Charm mesons - New L = 1 D, states. Analyses presented by BABAR [209 and CLEO in the spring of 2003 are challenging the whole picture.
TABLE III.— Winter ’02/’03 status of (L=1, n=1) and (L=0, n=2) cq and cS mesons (MeV). Statistical and systematical errors added in quadrature. Experimental results not included in PDG are from BELLE [199, CLEO [i96J, DELPHI [200], FOCUS (207) (202). Theory predictions from (203). 6°3.3. Charm mesons - New L = 1 D, states. Analyses presented by BABAR [209 and CLEO in the spring of 2003 are challenging the whole picture.
Fig. 16.— New D*,, (2317) and D*,, (2463) states observed by BABAR (a,b) (209) and CLE (c,d) 210).
Fig. 16.— New D*,, (2317) and D*,, (2463) states observed by BABAR (a,b) (209) and CLE (c,d) 210).
TABLE IV. — Comparison of SELEX and FOCUS results on double-charm baryons (from [235y) Limits are at the 90% cl.
TABLE IV. — Comparison of SELEX and FOCUS results on double-charm baryons (from [235y) Limits are at the 90% cl.
TABLE V. — Summary of world averages from [Z3i), new results, and updated world averages. Statistical and systematical errors are summed in quadrature. itself, does allow lifetime determination at the level of 15%.
TABLE V. — Summary of world averages from [Z3i), new results, and updated world averages. Statistical and systematical errors are summed in quadrature. itself, does allow lifetime determination at the level of 15%.
Fig. 22. — Cutting an internal quark line generates order 1/ ms four fermion operators. a) Weak annihilation in mesonic decays. d) Pauli Interference in the decays of a meson. c) Weak scattering in baryonic decays. d) Pauli Interference in the decays of a baryon.
Fig. 22. — Cutting an internal quark line generates order 1/ ms four fermion operators. a) Weak annihilation in mesonic decays. d) Pauli Interference in the decays of a meson. c) Weak scattering in baryonic decays. d) Pauli Interference in the decays of a baryon.
TABLE VI. — Lifetime ratios in the charm sector
TABLE VI. — Lifetime ratios in the charm sector
(?°)One should note that the description through fp, as defined by Eq. (T42) holds irrespective of the existence of a wave function. One expects the following branching ratios for the D+ and D+ modes, which are Cabibbo allowed and forbidden, respectively: These transitions are helicity suppressed ; i.e., the amplitude is proportional to me, the mass of the lepton @, in complete analogy to m+ — &+v. This property holds in general for any (axial)vector charged current — a point we will return to below. They are also suppressed by fp, < me. This feature can be understood intuitively: due to the practically zero range of the weak forces the ¢ and 3 or d quarks have to come together to annihilate. The amplitude therefore is proportional to weq(0), the cg wave function at zero separation. This quantity is related to the decay constant as follows: f2 — 12/e5.-(0)|2/Mn (2°).
(?°)One should note that the description through fp, as defined by Eq. (T42) holds irrespective of the existence of a wave function. One expects the following branching ratios for the D+ and D+ modes, which are Cabibbo allowed and forbidden, respectively: These transitions are helicity suppressed ; i.e., the amplitude is proportional to me, the mass of the lepton @, in complete analogy to m+ — &+v. This property holds in general for any (axial)vector charged current — a point we will return to below. They are also suppressed by fp, < me. This feature can be understood intuitively: due to the practically zero range of the weak forces the ¢ and 3 or d quarks have to come together to annihilate. The amplitude therefore is proportional to weq(0), the cg wave function at zero separation. This quantity is related to the decay constant as follows: f2 — 12/e5.-(0)|2/Mn (2°).
The numbers have been scaled to the lattice estimates of the decay constants. PE cd i Bice: sbi: seas Pees | co ees: weer eres PE: et en ee Ei a ee ee eae wecaase sae “ The fact that there are two different mesons decaying in this way represents an extra bonus. Only lattice QCD could provide us with predictions for the decay constants fp and fp, with a theoretical uncertainty not exceeding a few percent. Yet one has to be concerned that maybe not all lattice artefacts can be brought under such excellent control. These systematics should however basically cancel in the ratio fp, /fp, which deviates from unity only due to SU(3) 7; breaking. The motivation for measuring these widths thus lies in extracting the decay constants as a precision measure for the theoretical control lattice QCD can achieve over certain hadronic quantities. Even more importantly lattice QCD successfully passing this test constitutes an important validation for its prediction on fp,,. It has been suggested that even if lattice QCD falls somewhat short of a successful prediction for fp, one can use the experimentally observed value for fp together with lattice QCD’s prediction for fe/fp to arrive at a reliable value for fg, which obviously is of the greatest benefit for interpreting B° — B® oscillations; at the very least success in reproducing fp, /fp would tightly constrain fs, /fs, which controls B, — B, vs. Ba — Bg oscillations. These transitions are sometimes advanced as sensitive nrohes for New Physics in the
The numbers have been scaled to the lattice estimates of the decay constants. PE cd i Bice: sbi: seas Pees | co ees: weer eres PE: et en ee Ei a ee ee eae wecaase sae “ The fact that there are two different mesons decaying in this way represents an extra bonus. Only lattice QCD could provide us with predictions for the decay constants fp and fp, with a theoretical uncertainty not exceeding a few percent. Yet one has to be concerned that maybe not all lattice artefacts can be brought under such excellent control. These systematics should however basically cancel in the ratio fp, /fp, which deviates from unity only due to SU(3) 7; breaking. The motivation for measuring these widths thus lies in extracting the decay constants as a precision measure for the theoretical control lattice QCD can achieve over certain hadronic quantities. Even more importantly lattice QCD successfully passing this test constitutes an important validation for its prediction on fp,,. It has been suggested that even if lattice QCD falls somewhat short of a successful prediction for fp, one can use the experimentally observed value for fp together with lattice QCD’s prediction for fe/fp to arrive at a reliable value for fg, which obviously is of the greatest benefit for interpreting B° — B® oscillations; at the very least success in reproducing fp, /fp would tightly constrain fs, /fs, which controls B, — B, vs. Ba — Bg oscillations. These transitions are sometimes advanced as sensitive nrohes for New Physics in the
Fig. 24. — Semileptonic D° decay due to the coupling of a virtual D*(c5) vector state in the nearest-pole dominance model (left); |f+(q?)|? as a function of q? for pole and HQET parameterizations. The kinematic limits for K €v and 7év are drawn with vertical lines (adapted from [298]).
Fig. 24. — Semileptonic D° decay due to the coupling of a virtual D*(c5) vector state in the nearest-pole dominance model (left); |f+(q?)|? as a function of q? for pole and HQET parameterizations. The kinematic limits for K €v and 7év are drawn with vertical lines (adapted from [298]).
Fig. 25. — A comparison of various lattice predictions for the semi-leptonic differential decay width as a function of the pion energy E: diamonds [303],triangles [304], and squares [B01]. This plot is taken from reference [B01].
Fig. 25. — A comparison of various lattice predictions for the semi-leptonic differential decay width as a function of the pion energy E: diamonds [303],triangles [304], and squares [B01]. This plot is taken from reference [B01].
Fig. 26. — Compilation of experimental results on semileptonic vector formfactor ratios. Error bars show the statistical error, and the statistical and systematic added in quadrature. PDG03 updated averages to 2002 [[31] are shown in the boxed area. PDG03 applies a 1.5 factor on the error of ry world average for Dt — K*°etiy.
Fig. 26. — Compilation of experimental results on semileptonic vector formfactor ratios. Error bars show the statistical error, and the statistical and systematic added in quadrature. PDG03 updated averages to 2002 [[31] are shown in the boxed area. PDG03 applies a 1.5 factor on the error of ry world average for Dt — K*°etiy.
107 TABLE IX. — Predictions for various semileptonic decay rates in 10'°s~?.
107 TABLE IX. — Predictions for various semileptonic decay rates in 10'°s~?.
TABLE X. — Predictions for Ds semileptonic decay rates in 10'°s. To conclude this subsection, we remind another example of unexpected surge of con- nection between charm semileptonics decays, and light flavour hadronic physics (see Sect[82.1). The recent evidence for a broad S-wave resonant component in Dt —> (K7)£v can possibly be related to the debated observation of the & resonance in Dalitz
TABLE X. — Predictions for Ds semileptonic decay rates in 10'°s. To conclude this subsection, we remind another example of unexpected surge of con- nection between charm semileptonics decays, and light flavour hadronic physics (see Sect[82.1). The recent evidence for a broad S-wave resonant component in Dt —> (K7)£v can possibly be related to the debated observation of the & resonance in Dalitz
TABLE XI.— World averages for charm mesons and baryons absolute branching ratios from [731y
TABLE XI.— World averages for charm mesons and baryons absolute branching ratios from [731y
Using the most recent PDG values for the branching ratios one infers We can easily see that FSI produce generally large phase shifts by using isospin decom- positions of decay amplitudes. Consider the modes D — K7: there are three channels —~ D®° — K-xt, D® — K°r® and Dt — K°xt — yet only two independent ampli- tudes, namely with isospin 1/2 and 3/2 in the final state, T1 and Ts, respectively. Thus there has to be a relation between the three (complex) transition amplitudes; i.e., they have to form a triangle relation, which is easily worked out:
Using the most recent PDG values for the branching ratios one infers We can easily see that FSI produce generally large phase shifts by using isospin decom- positions of decay amplitudes. Consider the modes D — K7: there are three channels —~ D®° — K-xt, D® — K°r® and Dt — K°xt — yet only two independent ampli- tudes, namely with isospin 1/2 and 3/2 in the final state, T1 and Ts, respectively. Thus there has to be a relation between the three (complex) transition amplitudes; i.e., they have to form a triangle relation, which is easily worked out:
126 TABLE XIII. — Recent results not included in PDGO2 on 2-body and >2-body charm mesons and baryons absolute branching ratios. Last column shows ratio of relative errors on branching fractions of normalizing mode and decay mode.
126 TABLE XIII. — Recent results not included in PDGO2 on 2-body and >2-body charm mesons and baryons absolute branching ratios. Last column shows ratio of relative errors on branching fractions of normalizing mode and decay mode.
129
129
TABLE XVI. — Branching ratios for Cabibbo-forbidden decays of D* and Dz mesons along with predictions for CP asymmetries
TABLE XVI. — Branching ratios for Cabibbo-forbidden decays of D* and Dz mesons along with predictions for CP asymmetries
131 TABLE XVII. — Branching ratios for Cabibbo suppressed decays of D° mesons along with pre- dictions for CP asymmetries
131 TABLE XVII. — Branching ratios for Cabibbo suppressed decays of D° mesons along with pre- dictions for CP asymmetries
TABLE XVIII. — Theoretical predictions and experimental values for the branching ratios of various Double-Cabibbo forbidden decays.
TABLE XVIII. — Theoretical predictions and experimental values for the branching ratios of various Double-Cabibbo forbidden decays.
over the D* width [362]. It was claimed that finding it would amount to a ‘smoking gun’ evidence supporting this assumption. Afterwards it was indeed found — with close to the predicted branching ratio: BR(D° — Ks@) = (0.47 + 0.06) %. In retrospect, however, it should be viewed as evidence for the impact FSI can have.
over the D* width [362]. It was claimed that finding it would amount to a ‘smoking gun’ evidence supporting this assumption. Afterwards it was indeed found — with close to the predicted branching ratio: BR(D° — Ks@) = (0.47 + 0.06) %. In retrospect, however, it should be viewed as evidence for the impact FSI can have.
‘ig. 30. — Charm meson decay represented via an s-channel process via resonance propagator r
‘ig. 30. — Charm meson decay represented via an s-channel process via resonance propagator r
TABLE XXII. — Fraction (%) of partial widths for charmed particles identified in exclusive modes, and fraction of exclusive modes identified as two or quasitwo body (hadronic) and three or qu- asithree (semileptonic). Data from PDG2002. No absolute branching fractions have been mea- sured for Ed. No branching fractions have been measured for =2 nor 2%.
TABLE XXII. — Fraction (%) of partial widths for charmed particles identified in exclusive modes, and fraction of exclusive modes identified as two or quasitwo body (hadronic) and three or qu- asithree (semileptonic). Data from PDG2002. No absolute branching fractions have been mea- sured for Ed. No branching fractions have been measured for =2 nor 2%.
denotes the ratio of instantaneous transition amplitudes with 6x, ~ O(1). We have re- tained terms of first and second order in the small parameters xp, yp that are enhanced by 1/tg?6c and 1/tg*6c, respectively. |[(D° — Ktx—)|?/|T(D®° — K-2x*)/? is where we have used the usual short-hand notation rp = r®-¢ (IF); we have also antici- pated or YD New P oscillat isaS classes that 72,, y?, < 1 and |q|? & |p|? hold. A signal is produced by either ep 4 0 # 0 or both. One should note that while rp ~ O is an unambiguous sign of hysics within the SM, it does not require very specific time features of D® — D® ions per se, as illustrated by the next example with ‘wrong-sign’ kaons. For there background — doubly Cabibbo suppressed decays (DCSD). Thus there are three of contributions, namely purely from DCSD, from D°D?® oscillations followed by a Cabi bbo allowed transition and from the interference between the two: (?7)We prefer the term ‘correct sign’ over ‘right sign’, since we do not share the often unreflected preference of the right over the left.
denotes the ratio of instantaneous transition amplitudes with 6x, ~ O(1). We have re- tained terms of first and second order in the small parameters xp, yp that are enhanced by 1/tg?6c and 1/tg*6c, respectively. |[(D° — Ktx—)|?/|T(D®° — K-2x*)/? is where we have used the usual short-hand notation rp = r®-¢ (IF); we have also antici- pated or YD New P oscillat isaS classes that 72,, y?, < 1 and |q|? & |p|? hold. A signal is produced by either ep 4 0 # 0 or both. One should note that while rp ~ O is an unambiguous sign of hysics within the SM, it does not require very specific time features of D® — D® ions per se, as illustrated by the next example with ‘wrong-sign’ kaons. For there background — doubly Cabibbo suppressed decays (DCSD). Thus there are three of contributions, namely purely from DCSD, from D°D?® oscillations followed by a Cabi bbo allowed transition and from the interference between the two: (?7)We prefer the term ‘correct sign’ over ‘right sign’, since we do not share the often unreflected preference of the right over the left.
where we have used the notation of Eq. (239). We see that the dependence on the (proper) time of decay t differentiates between DCSD, D°D® oscillations and their interference. 10°3. Theory expectations. — Within the SM two structural reasons combine to make Zp and yp small in contrast to the situation for B° — B® and K®° — K° oscillations: 4. The most direct signal for oscillations is the observation that decay rate evolution in time do not follow a strictly exponential law. For semileptonic transitions we have
where we have used the notation of Eq. (239). We see that the dependence on the (proper) time of decay t differentiates between DCSD, D°D® oscillations and their interference. 10°3. Theory expectations. — Within the SM two structural reasons combine to make Zp and yp small in contrast to the situation for B° — B® and K®° — K° oscillations: 4. The most direct signal for oscillations is the observation that decay rate evolution in time do not follow a strictly exponential law. For semileptonic transitions we have
Fig] shows a pictorial quark level illustration of the interplay between oscillations and DCSD processes. The wrong-sign events receive contributions from DCSD, D®°D® oscillations (followed by a Cabibbo allowed decays) and the interference between the two [427] [422] and that those can be distinguished and thus measured separately by their dependence on the (proper) time of decay, as stated above in Eq.@7Q: X and Z represent the DCSD and D® D” terms, respectively, and Y their interference. The latter receives a nonzero contribution from Im(2,2s+)), if there is a weak phase, which leads to CP violation as discussed later, and/or if a strong phase is present due to different FSI in D° — K+m~ and D° — Ktz-. One has to allow for such a difference since the latter is a pure AI = 1 transition, while the former is given by a combination of an enhanced AJ = O and a suppressed AT = 1 amplitude. Asevsengne OSD aAnoaeeadtsam Y a tha akeawnnn AC =palk ehaeaw “Semeliag HTMO —_«
Fig] shows a pictorial quark level illustration of the interplay between oscillations and DCSD processes. The wrong-sign events receive contributions from DCSD, D®°D® oscillations (followed by a Cabibbo allowed decays) and the interference between the two [427] [422] and that those can be distinguished and thus measured separately by their dependence on the (proper) time of decay, as stated above in Eq.@7Q: X and Z represent the DCSD and D® D” terms, respectively, and Y their interference. The latter receives a nonzero contribution from Im(2,2s+)), if there is a weak phase, which leads to CP violation as discussed later, and/or if a strong phase is present due to different FSI in D° — K+m~ and D° — Ktz-. One has to allow for such a difference since the latter is a pure AI = 1 transition, while the former is given by a combination of an enhanced AJ = O and a suppressed AT = 1 amplitude. Asevsengne OSD aAnoaeeadtsam Y a tha akeawnnn AC =palk ehaeaw “Semeliag HTMO —_«
Fig. 32. — Cartoon which explains at a quark-level (a) the two routes (DCS decays and mixing) to get to K+ x7 starting from a D®; (b) the one route (mixing) which is possible for semileptonic final state.
Fig. 32. — Cartoon which explains at a quark-level (a) the two routes (DCS decays and mixing) to get to K+ x7 starting from a D®; (b) the one route (mixing) which is possible for semileptonic final state.
TABLE XXIII. — Synopsis of recent D°D® mizing results. CPV phase is y, strong phase is 6, interference angle is 6 = arg(ix + y) — yp — 6. As instance, p #4 0 stands for no CP conservation is assumed.
TABLE XXIII. — Synopsis of recent D°D® mizing results. CPV phase is y, strong phase is 6, interference angle is 6 = arg(ix + y) — yp — 6. As instance, p #4 0 stands for no CP conservation is assumed.
Fig. 33. — Lifetime distributions used to extract lifetime asymmetry ycp (left) Fixed-target experiment FOCUS [433] (right) ete~ experiment BABAR [436].
Fig. 33. — Lifetime distributions used to extract lifetime asymmetry ycp (left) Fixed-target experiment FOCUS [433] (right) ete~ experiment BABAR [436].
Fig. 34. — Summary of 2’, y’,ycp measurements. The BABAR limits (solid contour: CP conservation assumed; dashed contour: CP conservation not assumed) were scaled to x’ from Ref. [437], and are superimposed for qualitative comparison.
Fig. 34. — Summary of 2’, y’,ycp measurements. The BABAR limits (solid contour: CP conservation assumed; dashed contour: CP conservation not assumed) were scaled to x’ from Ref. [437], and are superimposed for qualitative comparison.
TABLE XXIV. — Compilation of oscillation parameters (95% cl ) (137)
TABLE XXIV. — Compilation of oscillation parameters (95% cl ) (137)
While the rates depend on the time of decay in a non-trivial manner, the asymmetry does not.
While the rates depend on the time of decay in a non-trivial manner, the asymmetry does not.
Fig. 35. — Tree and penguin graphs for D+ — K*°K+. As explained before the leading term in the penguin diagram here represents a nonlocal operator, since the internal s quark in the loop is lighter than the external charm quark.
Fig. 35. — Tree and penguin graphs for D+ — K*°K+. As explained before the leading term in the penguin diagram here represents a nonlocal operator, since the internal s quark in the loop is lighter than the external charm quark.
TABLE XXV.— CP-violating asymmetries. Data from PDGO3 [73i) unless noted. Statistic and systematic errors are summed in quadrature. 11'5.1. Experimental limits. While no evidence for CPT breaking has been found, one should note that the purely empirical underpinning of CPT invariance — in contrast to its theoretical one — is not overly impressive [L07]. The ‘canonical’ tests concerning the equality in the masses and lifetimes of particles and antiparticles yield bounds of typically around 10~* for light flavour states. Some very fine work has been done on CPT tests in Ky decays. However even the often quoted bound |Mgo — Mxo|/Mx < 9-107? looks much more impressive than it actually is. For there is little justification of using Myx as yardstick (unless one wants to blame CPT violation on gravity); a better — yet still not well motivated — calibrator is the Kg width leading to |Mgo — Mxo|/TK, < 7-105. Intriguing future tests have been suggested for neutral K and B meson transitions [450}. Their sensitivity is enhanced by involving K° — K° and B® — B® oscillations and making use of EPR correlations in ete~ — $(1020) — K°K® and ete — Y(4S) — BaBa, respectively. Their analyses will be performed at DA®NE and by BELLE and BABAR. me ee «SCOR OS zo as ts
TABLE XXV.— CP-violating asymmetries. Data from PDGO3 [73i) unless noted. Statistic and systematic errors are summed in quadrature. 11'5.1. Experimental limits. While no evidence for CPT breaking has been found, one should note that the purely empirical underpinning of CPT invariance — in contrast to its theoretical one — is not overly impressive [L07]. The ‘canonical’ tests concerning the equality in the masses and lifetimes of particles and antiparticles yield bounds of typically around 10~* for light flavour states. Some very fine work has been done on CPT tests in Ky decays. However even the often quoted bound |Mgo — Mxo|/Mx < 9-107? looks much more impressive than it actually is. For there is little justification of using Myx as yardstick (unless one wants to blame CPT violation on gravity); a better — yet still not well motivated — calibrator is the Kg width leading to |Mgo — Mxo|/TK, < 7-105. Intriguing future tests have been suggested for neutral K and B meson transitions [450}. Their sensitivity is enhanced by involving K° — K° and B® — B® oscillations and making use of EPR correlations in ete~ — $(1020) — K°K® and ete — Y(4S) — BaBa, respectively. Their analyses will be performed at DA®NE and by BELLE and BABAR. me ee «SCOR OS zo as ts
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