From: intuitionist1@gmail.com   
      
   On Saturday, November 3, 2018 at 9:26:26 PM UTC+3, Lawrence Crowell wrote:   
   > On Saturday, November 3, 2018 at 4:57:56 AM UTC-6, Sabbir Rahman wrote:   
   > > On Friday, November 2, 2018 at 5:25:34 PM UTC+3, Lawrence Crowell wrote:   
   > > > On Friday, November 2, 2018 at 12:24:01 AM UTC-6, ben...@hotmail.com wr=   
   > ote:   
   > > > > On Thursday, November 1, 2018 at 10:21:57 PM UTC, Tom Roberts wrote:   
   > > > >> ...   
   > > > >> For test particles the GR prediction is unambiguous:=20   
   > > > >> regardless of the test particle's mass (including sign, if any) it=20   
   > > > >> "falls downward" toward a positive mass and "falls upward" away from=   
   >  a=20   
   > > > >> negative mass.   
   > > > >>   
   > > > >> While there is currently no experimental evidence of antimatter's=20   
   > > > >> behavior in gravity, the mass of every known antiparticle is=20   
   > > > >> unequivocally positive.   
   > > > >> ...   
   > > > >   
   > > > > I am not clear how it is shown that antimatter unequivocally has   
   > > > > positive mass?  As both positive and negative test masses are attract=   
   > ed   
   > > > > to the positive mass of the earth, then how can attraction to the ear=   
   > th   
   > > > > be used to distinguish between a positive and a negative test mass?   
   > > >=20   
   > > > It makes little sense that antimatter has negative inertial mass. The   
   > > > particle antiparticle interaction would give mc^2 - mc^2 =3D E =3D 0, w=   
   > here   
   > > > experiments measure photons. The gravitational mass is an open   
   > > > questions, and an experiment at CERN is being set up to measure this   
   > > > with anti-hydrogen atoms.   
   > > >=20   
   > > > LC   
   > >=20   
   > > This is actually not correct.   
   > >=20   
   > > If you take the time to work it out (by considering the interactions betw=   
   > een   
   > > the four classes of particles I mention), you will actually find that the   
   > > energy and momentum of a particle of type (I,A,P) has to have a factor of   
   > > IAP in front of the usual definition, so the momentum p =3D IAPmv, the ki=   
   > netic=20   
   > > energy E =3D IAPmv^2/2, and the rest mass energy is IAP mc^2.   
   > >=20   
   > > So your assumption that negative inertial mass implies negative energy is=   
   > =20   
   > > not correct in general.   
   > >=20   
   > > In actual fact, the rest mass energy is positive for particles of class A   
   > > and D, and negative for particles of class B and C.   
   > >=20   
   > > Now, antiparticles are of type D (well at least according to the claim ma=   
   > de   
   > > here), and therefore have positive energy, so the total energy released u=   
   > pon=20   
   > > annihilation of a particle-antiparticle pair is positive (and equal to=20   
   > > 2mc^2), as expected.   
   >   
   > You are sort of creating a physics that is at best nonstandard. Within that=   
   >  setting you claim my statement is false. Within standard physics I hold to=   
   >  what I claim. Now if antimatter changes the sign of gravitational mass, bu=   
   > t not inertial mass, then antimatter would fall upwards. This would be an a=   
   > dulteration of the Einstein equivalence principle. I doubt this is the case=   
   > , but the CERN experiment, a reference I sent yesterday, will demonstrate w=   
   > hether this is or is not the case.   
      
   I really don't think I am - it is just that until now no-one seems to have   
   bothered to sit down and go through the details carefully. That is why the   
   terminology and especially the signs are all over the place.   
      
   I actually did bother do sit down and go things properly, and if you allow   
   the signs of the inertial, active and passive gravitational mass to be   
   either positive or negative and then look carefully at the complete set of   
   possible interactions, then you can actually work out what the energy,   
   momentum and gravitational potential associated with each particle has to   
   be for consistency, and the answer is unique.   
      
   Here is the link to a preprint I have prepared where I actually do these   
   calculations as well as some accompanying N-body simulations:   
      
   https://www.researchgate.net/publication/328725835_On_the_existe   
   ce_of_exotic_matter_in_classical_Newtonian_mechanics   
      
   I hope that this helps to clear up some of the apparent confusion around this   
   subject.   
      
   --- SoupGate-Win32 v1.05   
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