Large Squark-Mixing Impact on H^+ Decay in the MSSM

We study the decays of the charged Higgs boson H^+ within the Minimal Supersymmetric Standard Model. We find that the supersymetric mode 'stop + sbottom-bar' can dominate the H^+ decays in a wide range of the model parameters due to the large Yukawa couplings and mixings of stop and sbottom. Compared to the conventional modes 'tau^+ nu' and 't b-bar', this mode has very distinctive signatures. This could have a decisive impact on H^+ searches at future colliders. We find also that the QCD corrections to the 'stop + sbottom-bar' mode are significant, but that they do not invalidate our tree-level conclusion above.Comment: 4 pages, latex, 1 eps figure, uses stwol.sty; Invited talk at the 28th International Conference on High Energy Physics, Warsaw, Poland, 25-31 July 1996 (to appear in the proceedings (World Scientific)

Impact of bosonic decays on the search for t~_1 and b~_1 squarks

We perform a detailed study of the decays of the lighter top and bottom squarks (t~_1 and b~_1) in the Minimal Supersymmetric Standard Model (MSSM). We show that the decays into Higgs or gauge bosons, i.e. t~_1 -> b~_1 + (H^+ or W^+) and b~_1 -> t~_1 + (H^- or W^-), can be dominant in a wide range of the MSSM parameters due to the large Yukawa couplings and mixings of t~ and b~. Compared to the decays into fermions, such as t~_1 -> t + (neutralino_i or gluino) and t~_1 -> b + chargino_j, these bosonic decay modes can have significantly different decay distributions. We also show that the effect of the supersymmetric QCD running of the quark and squark parameters on the t~_1 and b~_1 decay branching ratios is quite dramatic. These could have an important impact on the search for t~_1 and b~_1 and the determination of the MSSM parameters at future colliders.Comment: 14 pages, 4 figures, LaTeX2

Correlation between the decays h0→γγ/ggh^0 \to \gamma \gamma/g g in the MSSM with quark flavour violation

We study the loop-induced decays $h^0 \to \gamma \, \gamma$ and $h^0 \to g \, g$ in the Minimal Supersymmetric Standard Model (MSSM) with quark flavour violation (QFV), identifying $h^0$ with the Higgs boson with a mass of 125 GeV, where $\gamma$ and $g$ are photon and gluon, respectively. We perform a MSSM parameter scan and a detailed analysis around a fixed reference point respecting theoretical constraints from vacuum stability conditions and experimental constraints, such as those from B meson data and electroweak precision data, as well as recent limits on supersymmetric (SUSY) particle masses from LHC experiments. We find that (i) the relative deviation of the decay width $\Gamma(h^0 \to g \, g)$ from the Standard Model value, $DEV(g)$, can be large and negative, $\lesssim - 15\%$, (ii) the analogous deviation of $\Gamma(h^0 \to \gamma \, \gamma)$ is strongly correlated, $DEV(\gamma) \simeq -1/4\,DEV(g)$ for $DEV(g) \lesssim - 4\%$, (iii) the relative deviation of the width ratio $\Gamma(h^0 \to \gamma \, \gamma)/\Gamma(h^0 \to g \, g)$ from the SM value, $DEV(\gamma/g)$, can be large (up to $\sim$ 20\%), (iv) the deviations can be large due to the up-type squark loop contributions, (v) the SUSY QFV parameters can have a significant effect on these deviations. Such large deviations can be observed at a future $e^+e^-$ collider like ILC. Observation of the deviation patterns as shown in this study would favour the MSSM with flavour-violating squark mixings and encourage to perform further studies in this model.Comment: Version accepted for publication in IJMP

Impact of SUSY CP Phases on Stop and Sbottom Decays in the MSSM

We study the decays of top squarks and bottom squarks in the Minimal Supersymmetric Standard Model with complex parameters A_t, A_b and mu. In a large region of the supersymmetric parameter space the branching ratios of stop_1 and sbottom_1 show a pronounced phase dependence. This could have an important impact on the search for stop_1 and sbottom_1 at a future linear collider and on the determination of the supersymmetric parameters.Comment: 10 pages, LaTeX, 4 eps figures; contribution to the Extended Joint ECFA/DESY Study on Physics and Detectors for a Linear Electron-Positron Collider; v2: parameter space excluded by B(b -> s gamma) correcte

Higgs boson decay to charm pair at full one-loop level in the MSSM with flavour violation

We study the decay of the lightest neutral Higgs boson to a charm quark pair at full one-loop level in the MSSM with non-minimal quark flavour violation (QFV). In the numerical analysis we consider mixing between the second and the third squark generation and all relevant constraints from B meson data are taken into account. It is shown that the full one-loop corrected decay width can be quite sensitive to the MSSM QFV parameters due to large $\tilde c - \tilde t$ mixing and large trilinear couplings. After summarising the theoretical and experimental errors, we conclude that an observation of these SUSY QFV effects is possible at the ILC.Comment: 9 papes, 2 figures, talk presented at the International Workshop on Future Linear Colliders (LCWS14), Belgrade, Serbia, 6-10 October 201

The decays h0→bbˉh^0 \to b \bar{b} and h0→ccˉh^0 \to c \bar{c} in the light of the MSSM with quark flavour violation

We calculate the decay width of h0 -> b bbar in the Minimal Supersymmetric Standard Model (MSSM) with quark flavour violation (QFV) at full one-loop level. We study the effect of scharm-stop mixing and sstrange-sbottom mixing taking into account the constraints from the B meson data. We discuss and compare in detail the decays h0 -> c cbar and h0 -> b bbar within the framework of the perturbative mass insertion technique using the Flavour Expansion Theorem. The deviation of both decay widths from the Standard Model values can be quite large. Whereas in h0 -> c cbar it is almost entirely due to the flavour violating part of the MSSM, in h0 -> b bbar it is mainly due to the flavour conserving part. Nevertheless, the QFV contribution to Gamma(h0 -> b bbar) due to scharm-stop mixing and chargino exchange can go up to about 8%.Comment: Minor changes, version published in JHE

Improved SUSY QCD corrections to Higgs boson decays into quarks and squarks

We improve the calculation of the supersymmetric $O(\alpha_s)$ QCD corrections to the decays of Higgs bosons into quarks and squarks in the Minimal Supersymmetric Standard Model. In the on-shell renormalization scheme these corrections can be very large, which makes the perturbative expansion unreliable. This is especially serious for decays into bottom quarks and squarks for large $\tan\beta$. Their corrected widths can even become negative. We show that this problem can be solved by a careful choice of the tree-level Higgs boson couplings to quarks and squarks, in terms of the QCD and SUSY QCD running quark masses, running trilinear couplings $A_q$, and on-shell left-right mixing angles of squarks. We also present numerical results for the corrected partial decay widths for the large $\tan\beta$ case.Comment: Version to be published in PR

Impact of CP phases on the search for top and bottom squarks

We study the decays of top squarks (~t_{1,2}) and bottom squarks (~b_{1,2}) in the Minimal Supersymmetric Standard Model (MSSM) with complex parameters A_t, A_b, mu and M_1. We show that including the corresponding phases strongly affects the branching ratios of ~t_{1,2} and ~b_{1,2} decays in a large domain of the MSSM parameter space. This could have an important impact on the search for ~t_{1,2} and ~b_{1,2} and the determination of the underlying MSSM parameters at future colliders.Comment: 6 pages, 1 figure, Invited talk presented by K. Hidaka in The 12th International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY04), June 17-23, 2004, Tsukuba, Japa

Impact of quark flavor violation on the decay h0(125GeV)→ccˉh^0(125GeV) \to c\bar{c} in the MSSM

We compute the decay width of $h^0 \to c \bar{c}$ in the MSSM with quark flavor violation (QFV) at full one-loop level in the $\overline{\rm DR}$ renormalization scheme. We study the effects of $\tilde{c}-\tilde{t}$ mixing, taking into account the constraints on QFV from the B meson data. We find that the full one-loop corrected decay width $\Gamma(h^0 \to c \bar{c})$ is very sensitive to the MSSM QFV parameters. In a scenario with large $\tilde{c}_{L,R}-\tilde{t}_{L,R}$ mixing, $\Gamma (h^0 \to c \bar{c})$ can differ up to $\sim \pm 35\%$ from its SM value. After estimating the uncertainties of the width, we conclude that an observation of these QFV SUSY effects is possible at a future $e^+ e^-$ collider such as ILC.Comment: 4 pages, 2 figures, Proceedings of International Workshop on Higgs as a Probe of New Physics 2015 (HPNP2015), Toyama, Japan, 11-15, February, 2015 (to be published in eConf

Design of Quantum Annealing Machine for Prime Factoring

We propose a prime factoring machine operated in a frame work of quantum annealing (QA). The idea is inverse operation of a quantum-mechanically reversible multiplier implemented with QA-based Boolean logic circuits. We designed the QA machine on an application-specific-annealing-computing architecture which efficiently increases available hardware budgets at the cost of restricted functionality. The circuits are to be implemented and fabricated by using superconducting integrated circuit technology. We propose a three-dimensional packaging scheme of a qubit-chip / interposer / package-substrate structure for realizing practically-large scale QA systems.Comment: 3 pages, 6 figures, to appear in IEEE Xplore Conference Proceedings of the 16th International Superconductive Electronics Conference (ISEC 2017