A bottom-up approach to the strong CP problem

The strong CP problem is one of many puzzles in the theoretical description of elementary particle physics that still lacks an explanation. While top-down solutions to that problem usually comprise new symmetries or fields or both, we want to present a rather bottom-up perspective. The main problem seems to be how to achieve small CP violation in the strong interactions despite large CP violation in weak interactions. Observation of CP violation is exclusively through the Higgs--Yukawa interactions. In this paper, we show that with minimal assumptions on the structure of mass (Yukawa) matrices they do not contribute to the strong CP problem and thus we can provide a pathway to a solution of the strong CP problem within the structures of the Standard Model and no extension at the electroweak scale is needed. However, to address the flavor puzzle, models based on minimal SU(3) flavor groups leading to the proposed flavor matrices are favored. Though we refrain from an explicit a UV completion of the Standard Model, we provide a simple requirement those models should have to intrinsically not show a strong CP problem.Comment: 12 pages; v2: extended discussion, title changed to be more genera

El valor de la cartera de clientes de empresas de telecomunicaciones en México (The value of customer portfolio for telecommunication companies in Mexico)

Abstract. The purpose of this study is to determine which customers are more profitable. Companies must consider the income their customers generate, as well as the costs of acquiring and keeping them. However the analysis can’t end there, companies are well aware that, although customers´ past performance could be helpful to asses their future performance, it could also be tricky. Companies have started to pay attention to the unpredictable customers´ behavior, therefore, analyzing customers´ long term value, or even customers´ life time value (LTV). Nevertheless, only few companies have bothered to evaluate if their desirable individual customers are, from the risk stand point, are desirable collective customers based on the customers´ value change. The value of each customer changes to reflect the identity of the group it belongs to, as well as to reflect in advance, the effect it will have on it´s group. This analysis has been designed to obtain the correlation between the risk-return rate of a customer and a general portfolio as the result of customer´s contribution to the LTV of such portfolio in telecommunication companies. Resumen. Con el fin de determinar qué clientes serán más rentables, un negocio debe considerar en primer lugar los ingresos que éstos han estado generando y cuánto costará adquirirlos y mantenerlos. Pero el análisis no se puede detener ahí, las empresas son conscientes de que el desempeño pasado, si bien resulta útil para hacer predicciones, puede ser muy engañoso. Las empresas han comenzado a tratar el problema del comportamiento impredecible de los clientes. Los negocios se han dedicado al análisis del valor a largo plazo, o incluso el valor vitalicio del cliente individual, pero muy pocas se han molestado en evaluar si todos sus clientes individuales deseables son, desde el punto de vista del riesgo, deseables colectivamente. Puesto que el valor de un cliente cambia para reflejar tanto la identidad del grupo al que se suma como el efecto anticipado en la predictibilidad del mismo. Este análisis esta diseñado para captar la correlación entre la tasa riesgo-retorno del cliente y la de la cartera general teniendo como resultado la contribución al valor vitalicio al riesgo de una cartera de clientes de empresas de telecomunicaciones