An expression for the mass ?

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Discussion Overview

The discussion revolves around the calculation of mass in non-renormalizable theories using an infinite series representation. Participants explore the implications of truncating the series and expressing ultraviolet divergences recursively, questioning the validity and consequences of such approaches.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant proposes that in a non-renormalizable theory, the mass can be expressed as an infinite series involving divergences that can be recursively defined.
  • Another participant challenges the recursive definition of divergences, questioning how a divergence that is supposed to grow quadratically can be derived from a linear divergence.
  • A participant suggests that if a finite meaning could be assigned to certain integrals, it might allow for a recursive definition of all ultraviolet divergences.
  • There is a query about the nature of the difference between a sum and an integral, asking if it is always finite and if it can be expressed in terms of a constant dependent on a parameter.

Areas of Agreement / Disagreement

Participants express differing views on the validity of the recursive approach to defining divergences. There is no consensus on whether such a method can be applied universally or what the implications would be for physical parameters in non-renormalizable theories.

Contextual Notes

Limitations include the potential divergence of series and integrals discussed, as well as the dependence on the definitions and assumptions made regarding the divergences and their recursive relationships.

eljose
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An expression for the "mass"?..

Let,s suppose we have a NOn-renormalizable theory, and that we wish to calculate the mass of a particle for that theory with lagrangian L, the "mass" will have an expression in terms of an infinite series:

[tex]m \sim a(0)+ga(1)+g^{2}a(2)+g^{3}a(3)+...[/tex]


where every a(n) diverges in the form [tex]a(n)=\Lambda ^{n+1}[/tex] [tex]\Lambda \rightarrow \infty[/tex] (regulator)

then my question is let,s suppose we truncate the series for a number N :

[tex]m \sim a(0)+ga(1)+g^{2}a(2)+g^{3}a(3)+...g^{N}a(N)[/tex]

where g is a finite constant and N say N=139 (for example), of course in that case we have 139 types of divergences, but let,s suppose we could express every divergence recursively in the form:

.a(n)= c(n)+a(n-1)+a(n-2)+....+a(0) where c(n) are finite constants and a(0) is the value of the regulator, being this formula valid for every n=1,2,3,4,...139 so we could calculate our value for the mass in the form:

[tex]m \sim C(0)a(0)+gc(1)b(1)+g^{2}b(2)c(2)+g^{3}b(3)c(3)+...[/tex]

so we have only the divergence a(0) left, then we apply the renormalization process to 2absorb2 this a(0)-->k (finite value) so our finite value for the mass would be:

[tex]m \sim C(0)k+gc(1)b(1)+g^{2}b(2)c(2)+g^{3}b(3)c(3)+...g^{N}c(N)b(N)[/tex] finite due to the fact that c(n),b(n) and k are finite constants.

The question is if we could express always the ultraviolet divergences by a recursion formula...could we calculate any physical parameter truncating the series..even for Non-renormalizable theories?..thanks.
 
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Hmm; your statement,

[tex]a(n)=c(n)+a(n-1)+a(n-2)+\ldots+a(0)[/tex]​

doesn't sound quite right. Let us consider the case [itex]n=1[/itex] for your formula:

[tex]a(1)=c(1)+a(0).[/tex]​

You stated earlier that [itex]a(n)[/itex] diverges like [itex]\Lambda^{n+1}[/itex]. So, referring to the previous equation, since [itex]a(0)[/itex] diverges linearly and since you've fixed [itex]c(1)[/itex] to be a finite number, how could [itex]a(1)[/itex] possibly diverge quadratically?
 
Last edited:
eljose said:
Let,s suppose we have a NOn-renormalizable theory, and that we wish to calculate the mass of a particle for that theory with lagrangian L, the "mass" will have an expression in terms of an infinite series:

[tex]m \sim a(0)+ga(1)+g^{2}a(2)+g^{3}a(3)+...[/tex]


where every a(n) diverges in the form [tex]a(n)=\Lambda ^{n+1}[/tex] [tex]\Lambda \rightarrow \infty[/tex] (regulator)

then my question is let,s suppose we truncate the series for a number N :

[tex]m \sim a(0)+ga(1)+g^{2}a(2)+g^{3}a(3)+...g^{N}a(N)[/tex]

where g is a finite constant and N say N=139 (for example), of course in that case we have 139 types of divergences, but let,s suppose we could express every divergence recursively in the form:

.a(n)= c(n)+a(n-1)+a(n-2)+....+a(0) where c(n) are finite constants and a(0) is the value of the regulator, being this formula valid for every n=1,2,3,4,...139 so we could calculate our value for the mass in the form:

[tex]m \sim C(0)a(0)+gc(1)b(1)+g^{2}b(2)c(2)+g^{3}b(3)c(3)+...[/tex]

so we have only the divergence a(0) left, then we apply the renormalization process to 2absorb2 this a(0)-->k (finite value) so our finite value for the mass would be:

[tex]m \sim C(0)k+gc(1)b(1)+g^{2}b(2)c(2)+g^{3}b(3)c(3)+...g^{N}c(N)b(N)[/tex] finite due to the fact that c(n),b(n) and k are finite constants.

The question is if we could express always the ultraviolet divergences by a recursion formula...could we calculate any physical parameter truncating the series..even for Non-renormalizable theories?..thanks.
You can find the answer to your question in http://xxx.lanl.gov/abs/math-ph/0209025. It is the paper where to consider the case of non-Newtonians Physics where Lagrangian is depend of coordinates and momentums (velocity) only.
 
although it can be very 2fuzzy2 mi intention was to express every UV divergence recursively..so if we knew how to give a "finite" meaning to

[tex]\int_{0}^{\infty}dp[/tex]


we could give a 2finite2 meaning to every integral of the form:


[tex]\int_{0}^{\infty}dpp^{m}[/tex] m>0

via a recursion formula..of course this would imply that we should "truncate" the series for a finite m in case there are infinitely many m.

Another question, i have not been able to do that but...what would happen if we could obtain a finite value for the difference:

[tex]\sum_{n=0}^{\infty}n^{m}-\int_{0}^{\infty}dxx^{m}[/tex] m>0

Is always the difference above a finite quantity (let,s say C(m) where the constant C depends only on m a similar case is Euler Constant:

[tex]\sum_{N=1}^{K}n^{-1}-ln(K)=\gamma[/tex] K-->oo
 

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