Hand-Modelled Composite Prostheses after Resection of Peri-Acetabular Bone Malignancies

Purpose: To improve function after pelvic resection involving the acetabulum, using an anatomic composite implant built with screws and cement

Constraints on the phase γ\gamma and new physics from B→KπB\to K\pi Decays

Recent results from CLEO on $B\to K\pi$ indicate that the phase $\gamma$ may be substantially different from that obtained from other fit to the KM matrix elements in the Standard Model. We show that $\gamma$ extracted using $B\to K\pi, \pi\pi$ is sensitive to new physics occurring at loop level. It provides a powerful method to probe new physics in electroweak penguin interactions. Using effects due to anomalous gauge couplings as an example, we show that within the allowed ranges for these couplings information about $\gamma$ obtained from $B\to K \pi, \pi\pi$ can be very different from the Standard Model prediction.Comment: Revised version with analysis done using new data from CLEO. RevTex, 11 Pages with two figure

CP-Violating Asymmetries in Charmless Non-Leptonic Decays B→PP,PV,VVB \to PP, PV, VV in the Factorization Approach

We present estimates of the direct (in decay amplitudes) and indirect (mixing- induced) CP-violating asymmetries in the non-leptonic charmless two-body decay rates for $B \to PP$, $B \to PV$ and $B \to VV$ decays and their charged conjugates, where P(V) is a light pseudoscalar (vector) meson. These estimates are based on a generalized factorization approach making use of next-to-leading order perturbative QCD contributions which generate the required strong phases. No soft final state interactions are included. We study the dependence of the asymmetries on a number of input parameters and show that there are at least two (possibly three) classes of decays in which the asymmetries are parametrically stable in this approach. The decay modes of particular interest are: \optbar{B^0} \to \pi^+ \pi^-, \optbar{B^0} \to K_S^0 \pi^0, \optbar{B^0} \to K_S^0 \eta^\prime, \optbar{B^0} \to K_S^0 \eta and \optbar{B^0} \to \rho^+ \rho^-. Likewise, the CP-violating asymmetry in the decays \optbar{B^0} \to K_S^0 h^0 with $h^0=\pi^0,K_S^0, \eta,\eta^\prime$ is found to be parametrically stable and large. Measurements of these asymmetries will lead to a determination of the phases $\sin 2\alpha$ and $\sin 2 \beta$ and we work out the relationships in these modes in the present theoretical framework. We also show the extent of the so-called "penguin pollution" in the rate asymmetry $A_{CP}(\pi^+ \pi^-)$ and of the "tree shadow" in the asymmetry $A_{CP}(K_S^0\eta^\prime)$ which will effect the determination of $\sin 2 \alpha$ and $\sin 2 \beta$ from the respective measurements. CP-violating asymmetries in $B^\pm \to \pi^\pm \eta^\prime$, $B^\pm \to K^{*\pm} \eta$, $B^\pm \to K^{*\pm} \eta^\prime$ and $B^\pm \to K^{*\pm}\rho^0$ are potentially interesting and are studied here.Comment: 42 pages (LaTex) including 19 figures, requires epsfig.sty; submitted to Phys. Rev.

Flavour physics constraints in the BMSSM

We study the implications of the presence of the two leading-order, non-renormalizable operators in the Higgs sector of the MSSM to flavour physics observables. We identify the constraints of flavour physics on the parameters of the BMSSM when we: a) focus on a region of parameters for which electroweak baryogenesis is feasible, b) use a CMSSM-like parametrization, and c) consider the case of a generic NUHM-type model. We find significant differences as compared to the standard MSSM case.Comment: 22 pages, 7 figure

Novel sources of Flavor Changed Neutral Currents in the 331RHN331_{RHN} model

Sources of Flavor Changed Neutral Currents (FCNC) naturally emerge from a well motivated framework called 3-3-1 with right-handed neutrinos model, $331_{RHN}$ for short, mediated by an extra neutral gauge boson $Z^{\prime}$. Following previous works we calculate these sources and in addition we derive new ones coming from CP-even and -odd neutral scalars which appear due to their non-diagonal interactions with the physical standard quarks. Furthermore we show that bounds related to the neutral mesons systems $K_L-K_S$ and $D_1^0 - D_2^0$ may be significantly strengthened in the presence of these new interactions allowing us to infer stronger constraints on the parameter space of the model.Comment: Published version. 10 pages, 6 figure

Gravitino constraints on models of neutrino masses and leptogenesis

In the supersymmetric extensions of the standard model, neutrino masses and leptogenesis requires existence of new particles. We point out that if these particles with lepton number violating interactions have standard model gauge interactions, then they may not be created after reheating because of the gravitino problem. This will rule out all existing models of neutrino masses and leptogenesis, except the one with right-handed singlet neutrinos.Comment: 12 pages latex file with one postscript figur

Lepton Flavor Violation in Z and Lepton Decays in Supersymmetric Models

The observation of charged lepton flavor non-conservation would be a clear signature of physics beyond the Standard Model. In particular, supersymmetric (SUSY) models introduce mixings in the sneutrino and the charged slepton sectors which could imply flavor-changing processes at rates accessible to upcoming experiments. In this paper we analyze the possibility to observe Z --> lep_I lep_J in the GigaZ option of TESLA at DESY. We show that although models with SUSY masses above the current limits could predict a branching ratio BR(Z --> mu e) accessible to the experiment, they would imply an unobserved rate of mu --> e gamma and thus are excluded. In models with a small mixing angle between the first and the third (or the second and the third) slepton families GigaZ could observe Z --> tau mu (or Z --> tau e) consistently with present bounds on lep_J --> lep_I gamma. In contrast, if the mixing angles between the three slepton families are large the bounds from mu --> e gamma push these processes below the reach of GigaZ. We show that in this case the masses of the three slepton families must be strongly degenerated (with mass differences of order 10^{-3}). We update the limits on the slepton mass insertions delta_{LL,RR,LR} and discuss the correlation between flavor changing and g_mu-2 in SUSY models.Comment: 23 pages, 6 figures. Version to appear in Phys. Rev.

Baryogenesis at Low Reheating Temperatures

We note that the maximum temperature during reheating can be much greater than the reheating temperature $T_r$ at which the Universe becomes radiation dominated. We show that the Standard Model anomalous $(B+L)$-violating processes can therefore be in thermal equilibrium for 1 GeV \simlt T_{r}\ll 100 GeV. Electroweak baryogenesis could work and the traditional upper bound on the Higgs mass coming from the requirement of the preservation of the baryon asymmetry may be relaxed. Alternatively, the baryon asymmetry may be reprocessed by sphaleron transitions either from a $(B-L)$ asymmetry generated by the Affleck-Dine mechanism or from a chiral asymmetry between $e_R$ and $e_L$ in a $B-L = 0$ Universe. Our findings are also relevant to the production of the baryon asymmetry in large extra dimension models.Comment: 4 pages, version to appear in PRL: references added, new titl

Light Stop Decay in the MSSM with Minimal Flavour Violation

In supersymmetric scenarios with a light stop particle $\tilde{t}_1$ and a small mass difference to the lightest supersymmetric particle (LSP) assumed to be the lightest neutralino, the flavour changing neutral current decay $\tilde{t}_1 \to c \tilde{\chi}_1^0$ can be the dominant decay channel and can exceed the four-body stop decay for certain parameter values. In the framework of Minimal Flavour Violation (MFV) this decay is CKM-suppressed, thus inducing long stop lifetimes. Stop decay length measurements at the LHC can then be exploited to test models with minimal flavour breaking through Standard Model Yukawa couplings. The decay width has been given some time ago by an approximate formula, which takes into account the leading logarithms of the MFV scale. In this paper we calculate the exact one-loop decay width in the framework of MFV. The comparison with the approximate result exhibits deviations of the order of 10% for large MFV scales due to the neglected non-logarithmic terms in the approximate decay formula. The difference in the branching ratios is negligible. The large logarithms have to be resummed. The resummation is performed by the solution of the renormalization group equations. The comparison of the exact one-loop result and the tree level flavour changing neutral current decay, which incorporates the resummed logarithms, demonstrates that the resummation effects are important and should be taken into account.Comment: 29 page