We will also include in our calculation a plausible background model to take into account a possible primary component of astrophysical origin in the positron flux , which is likely to exist and which presumably provides the additional source of positrons when the dark matter annihilations or decays can not totally explain the rise in the positron fraction (for example , when the dark matter mass is smaller than 300 GeV or when the annihilation cross section or decay rate is too small). Besides,mostanalysesneglectthepositrondataatlowenergies(seehoweverrecentanalyses[16,17]wherethelowenergydataofthepositronfractionwasused).Nevertheless,theexquisitemeasurementsprovidedbyexperiments,togetherwiththeexcellentagreementoftheobservationswiththeexpectationsfromnon-exoticphysicswhichleavelittleroomforanexoticcomponentinthepositronfraction,allowustosetverystringentboundsonthedarkmatterproperties.