Desarrollo de software para el aprendizaje y razonamiento probabilístico: el caso de SIMULAPROB

Se discute el desarrollo y puesta a prueba de un software para apoyar la enseñanza y aprendizaje de la probabilidad desde un enfoque frecuencial. El software ha sido desarrollado en lenguaje JAVA bajo principios constructivistas de aprendizaje y considerando sugerencias de la investigación en educación estadística. El software permite abordar conceptos como aleatoriedad, noción frecuencial de la probabilidad, espacio muestral, modelos de urna, distribuciones de probabilidad (binomial e hipergeométrica); además permite explorar resultados teóricos y empíricos y el efecto que el número de simulaciones tiene en dichos resultados

Cosmological Constraints and SU(5) Supergravity Grand Unification

The predictions of SU(5) supergravity models with radiative breaking constrained by experimental proton decay bounds are discussed. It is shown that cosmological constraints further restrict the parameter space but can be satisfied for a wide range of parameters. It is also shown that no serious fine tuning problems (either at $M_{SUSY}$ or $M_{GUT}$) exist.Comment: 11page

Bottom-Up Approach to Uniefied Supergravity Models

A new approach is proposed to phenomenological study of a generic unified supergravity model, which reduces to the minimal supersymmetric standard model. The model is effectively parametrized in terms of five low energy observables. In consequence, it is easy to investigate systematically the parameter space of the model, allowed by the requirement of radiative electroweak symmetry breaking and by the present experimental limits. Radiative corrections due to large Yukawa couplings and particle--sparticle mass splitting are included into the analysis and found to have important effects, in particular on the degree of fine tuning in the model. In this framework there are presented the predictions of the model for various low energy physical observables and their dependence on the values of the top quark mass and $\tan\beta$ is discussed. Results are also given for the large $\tan\beta$ scenario, $\tan\beta\approx m_t/m_b$. Our approach can be easily extended to non--minimal supergravity models, which do not assume the universality of the soft breaking parameters at the unification scale $M_X$. Such an extension will be particularly useful once the masses of some sparticles are known, allowing for a model independent study of the parameter space at $M_X$.Comment: 38 pages, 17 figures (not included, may be sent on request), LaTex, MPI-Ph/92-11

Status of the superworld: from theory to experiment

Review to appear in Progress in Particle and Nuclear Physics. Contents: {1}Introduction}{1} {2}High precision LEP data and convergence of couplings: physics is not Euclidean geometry}{2} {3}Interconnections between the measured quantities due to Unification}{7} {4}The origin of $M_{SUSY}$ and why it should be abandoned: masses and spectra are needed}{13} {5}The new step forward: Supergravity}{21} {6}The SU(5) Supergravity Model}{22} {7}SU(5)xU(1) Supergravity}{32} {8}Detailed calculations for the Tevatron}{47} {9}Detailed calculations for LEP}{48} {10}Detailed calculations for HERA}{53} {11}Detailed calculations for Underground Labs and Underwater facilities}{55} {12}Detailed calculations for indirect experimental detection}{65} {13}The problem of mass and $m_t$}{73} {14}Conclusions}{77}Comment: 90 pages, 41 figures (not included), latex. Send requests for hard copies to "[email protected]". CERN-TH.7136/94, CTP-TAMU-80/9

Fermion masses and mixing angles from gauge symmetries

The structure of the quark and lepton masses and mixing angles provides one of the few windows we have on the underlying physics generating the \sm. In an attempt to identify the underlying symmetry group we look for the simplest gauge extension of the SUSY standard model capable of generating the observed structure. We show that the texture structure and hierarchical form found in the (symmetric) quark and lepton mass matrices follows if one extends the gauge group of the standard model to include an horizontal $U(1)$ gauge factor, constrained by the need for anomaly cancellation. This $U(1)$ symmetry is spontaneously broken slightly below the unification/string scale leaving as its only remnant the observed structure of masses and mixings. Anomaly cancellation is possible only in the context of superstring theories via the Green Schwarz mechanism with $sin^2(\theta_W)=3/8$.Comment: 19 pages, preprint numbers OUTP-9403 and FTUAM-94/7, LaTe

Testing Supergravity Grand Unification at Future Accelerator and Underground Experiments

The full parameter space of supergravity grand unified theory with $SU(5)$ type $p \rightarrow \bar{\nu} K$ proton decay is analysed using renormalization group induced electroweak symmetry breaking under the restrictions that the universal scalar mass $m_o$ and gluino mass are $\leq 1$ TeV (no extreme fine tuning) and the Higgs triplet mass obeys $M_{H_3}/M_G < 10$. Future proton decay experiments at SuperKamiokande or ICARUS can reach a sensitivity for the $\bar{\nu} K$ mode of $(2-5) \times 10^{33}$ yr allowing a number of predictions concerning the SUSY mass spectrum. Thus either the $p \rightarrow\bar{\nu} K$ decay mode will be seen at these experiments or a chargino of mass $m_{\tilde{W}} < 100$ GeV will exist and hence be observable at LEP2. Further, if $(p \rightarrow \bar{\nu} K) > 1.5 \times 10^{33}$ yr, then either the light Higgs has mass $m_h \leq 95$ GeV or $m_{\tilde{W}} \leq 100$ GeV i.e. either the light Higgs or the light chargino (or both) would be observable at LEP2. Thus, the combination of future accelerator and future underground experiments allow for strong experimental tests of this theory.Comment: 7 figures available upon request, CTP-TAMU-32/93, NUB-TH-3066/93 and SSCL-Preprint-44

Low Energy Thresholds and the Scalar Mass Spectrum in Minimal Supersymmetry

We discuss low energy threshold effects and calculate the sparticle masses in the context of the Minimal Supersymmetric Standard Model. We pay particular attention to the top squark and the Higgs mass parameters, and calculate the top Yukawa corrections, taking into account the successive decoupling of each particle at its threshold. We discuss the phenomenological implications in the context of the radiative symmetry breaking scenario.Comment: (CERN-TH.7411, Latex file, 12p, 1fig. not included

Detecting Physics At The Post-GUT And String Scales By Linear Colliders

The ability of linear colliders to test physics at the post-GUT scale is investigated. Using current estimates of measurements available at such accelerators, it is seen that soft breaking masses can be measured with errors of about (1-20)%. Three classes of models in the post-GUT region are examined: models with universal soft breaking masses at the string scale, models with horizontal symmetry, and string models with Calabi-Yau compactifications. In each case, linear colliders would be able to test directly theoretical assumptions made at energies beyond the GUT scale to a good accuracy, distinguish between different models, and measure parameters that are expected to be predictions of string models.Comment: Latex, 21 pages, no figure

Gauge Coupling Unification in GUT and String Models

The results for the running of the gauge couplings in the MSSM are up-dated by proper inclusion of all low scale effects. They are presented as predictions for the strong coupling constant in the scenario with only two parameters at the GUT scale ~ ($\alpha_{U}$ ~and ~$M_{U}$) ~and as a mismatch of the couplings at the scales ~$\sim 3 \times 10^{16}$ GeV ~and ~$4\times10^{17}$ GeV, when all three couplings are taken as the experimental input.Comment: 13 pages, raw latex, additional file contains uuencoded figure