Precision Flavour Physics with B→KννˉB\to K\nu\bar\nu and B→Kl+l−B\to Kl^+l^-

We show that a combined analysis of $B\to K\nu\bar\nu$ and $B\to Kl^+l^-$ allows for new physics tests practically free of form factor uncertainties. Residual theory errors are at the level of several percent. Our study underlines the excellent motivation for measuring these modes at a Super Flavour Factory.Comment: 26 pages, 2 figure

A Uniform Description of the States Recently Observed at B-factories

The newly found states Y(4260), Y(4361), Y(4664) and Z$^\pm$(4430) stir broad interest in the study of spectroscopy in a typical charmonium scale. The Y(4260) which was observed earlier has been interpreted as hybrid, molecular state, and baryonium, etc. In this note we show for the first time that these new structures, which are hard to be interpreted as charmonium states, can be systematically embedded into an extended baryonium picture. According to this assignment, the so far known characters of these states are understandable. And, in the same framework, we make some predictions for experimenters to measure in the future.Comment: 6 pages in Latex. to appear in J.Phys.

Partial waves of baryon-antibaryon in three-body B meson decay

The conspicuous threshold enhancement has been observed in the baryon-antibaryon subchannels of many three-body B decay modes. By examining the partial waves of baryon-antibaryon, we first show for B- -->pp-bar K- that the pK- angular correlation rules out dominance of a single pp-bar partial wave for the enhancement, for instance, the resonance hypothesis or the strong final-state interaction in a single channel. The measured pK- angular correlation turns out to be opposite to the naive expectation of the short-distance picture. We study the origin of this reversed angular correlation in the context of the pp-bar partial waves and argue that NN-bar bound states may be the cause of this sign reversal. Dependence of the angular correlation on the pp-bar invariant mass is very important to probe the underlying problem from the experimental side.Comment: 16 pages, 9 figures, the version for journal publicatio

How Resonances can synchronise with Thresholds

The mechanism by which a threshold may capture a resonance is examined. It involves a threshold cusp interfering constructively with either or both (i) a resonance produced via confinement, (ii) attractive t- and u-channel exchanges. The fo(980), X(3872) and Z(4430) are studied in detail. The fo(980) provides a valuable model of the locking mechanism. The X(3872) is too narrow to be fitted by a cusp, and requires either a resonance or virtual state. The Z(4430) can be fitted as a resonance but also can be fitted successfully by a cusp with no nearby resonant pole.Comment: 19 pages, 6 figures. Replaces 0709.125

Pediatric toxic polycystic thyroid

Background: Polycystic thyroid disease (PCTD) is a rare condition and has been described in adults in the setting of subclinical and clinical hypothyroidism. We present the first known case of a pediatric patient with diffuse macrocystic degeneration of the thyroid. Clinical presentation: A 6-year-old previously healthy patient was evaluated after presenting with a 16-month history of an enlarging polycystic thyroid and hyperthyroidism. Markers of autoimmune thyroid disease including thyroid stimulating immunoglobulin (TSI), thyroid stimulating hormone (TSH) receptor antibody, thyroid peroxidase antibody and thyroglobulin antibody were negative. No family history of benign or malignant thyroid or cystic disease was present. The patient underwent a total thyroidectomy without perioperative complication. She remains euthyroid with thyroid hormone replacement therapy. Summary: To our knowledge, this is the first report of PCTD in the pediatric population associated with hyperthyroidism without evidence of autoimmune disease. Somatic activating thyrotropin-receptor gene mutations are known to cause non-autoimmune hyperthyroidism in children, however it is unknown if similar mechanisms are responsible for pediatric PCTD. Conclusions: Polycystic thyroid degeneration can occur in children and may result in a hyperthyroid state

Measurement of the τ-lepton Lifetime at Belle

The lifetime of the τ lepton is measured using the process e+e−→τ+τ−, where both τ leptons decay to 3πντ. The result for the mean lifetime, based on 711  fb−1 of data collected with the Belle detector at the ϒ(4S) resonance and 60  MeV below, is τ=(290.17±0.53(stat)±0.33(syst))×10−15  s. The first measurement of the lifetime difference betweenτ+ and τ− is performed. The upper limit on the relative lifetime difference between positive and negative τ leptons is |Δτ|/τ\u3c7.0×10−3 at 90% C.L

Obtaining CKM Phase Information from B Penguin Decays

We discuss a method for extracting CP phases from pairs of B decays which are related by flavor SU(3). One decay (B0 -> M1 M2) receives a significant bbar -> dbar penguin contribution. The second (B' -> M1' M2') has a significant bbar -> sbar penguin contribution, but is dominated by a single amplitude. CP phase information is obtained using the fact that the B' -> M1' M2' amplitude is related by SU(3) to a piece of the B0 -> M1 M2 amplitude. The leading-order SU(3)-breaking effect (~25%) responsible for the main theoretical error can be removed. For some decay pairs, it can be written in terms of known decay constants. In other cases, it involves a ratio of form factors. However, this form-factor ratio can either be measured experimentally, or eliminated by considering a double ratio of amplitudes. In all cases, one is left only with a second-order effect, ~5%. We find twelve pairs of B decays to which this method can be applied. Depending on the decay pair, we estimate the total theoretical error in relating the B' -> M1' M2' and B0 -> M1 M2 amplitudes to be between 5% and 15%. The most promising decay pairs are Bd -> pi+ pi- and Bu+ -> K0 pi+, and Bd -> D+ D- and Bd -> Ds+ D- or Bu+ -> Ds+ D0bar.Comment: 38 pages, JHEP format, no figures. Comments added to text regarding most promising decay pairs; references added; conclusions unchange

The CKM Matrix and The Unitarity Triangle: Another Look

The unitarity triangle can be determined by means of two measurements of its sides or angles. Assuming the same relative errors on the angles $(\alpha,\beta,\gamma)$ and the sides $(R_b,R_t)$, we find that the pairs $(\gamma,\beta)$ and $(\gamma,R_b)$ are most efficient in determining $(\bar\varrho,\bar\eta)$ that describe the apex of the unitarity triangle. They are followed by $(\alpha,\beta)$, $(\alpha,R_b)$, $(R_t,\beta)$, $(R_t,R_b)$ and $(R_b,\beta)$. As the set \vus, \vcb, $R_t$ and $\beta$ appears to be the best candidate for the fundamental set of flavour violating parameters in the coming years, we show various constraints on the CKM matrix in the $(R_t,\beta)$ plane. Using the best available input we determine the universal unitarity triangle for models with minimal flavour violation (MFV) and compare it with the one in the Standard Model. We present allowed ranges for $\sin 2\beta$, $\sin 2\alpha$, $\gamma$, $R_b$, $R_t$ and $\Delta M_s$ within the Standard Model and MFV models. We also update the allowed range for the function $F_{tt}$ that parametrizes various MFV-models.Comment: "published version. few typos corrected, results unchanged