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documentation:ref:setmandelstam5 [2015/11/20 20:49]
poslavskysv created
documentation:ref:setmandelstam5 [2016/06/21 09:53]
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-====== setMandelstam5 ====== 
----- 
-====Description==== 
  
-  * ''​setMandelstam5([k1:​m1,​ k2:m2, k3:m3, k4:m4, k5:​m5])'' ​ generates a list of generalised Mandelstam and mass shell substitutions for incoming particles with momentums ''​k1'',​ ''​k2''​ and ''​k3''​ with masses ''​m1'',​ ''​m2''​ and ''​m3''​ and outcoming particles with momentums ''​k4''​ and ''​k5''​ with masses ''​m4''​ and ''​m5''​. 
- 
- 
-  * ''​setMandelstam5([k1:​m1,​ k2:m2, k3:m3, k4:m4, k5:m5], s, t1, t2, u1, u2)'' ​ generates a list of Mandelstam substitutions with specified notation for generalised Mandelstam s, t1, t2, u1 and u2 variables. 
- 
-  * ''​setMandelstam5''​ uses the following definition of Mandelstam variables: 
-\begin{gather*} 
-s = (p_1 + p_2)^2\\ 
-t_1 = (p_1 - p_3)^2 \\ 
-t_2 = (p_1 - p_4)^2 \\ 
-u_1 = (p_2 - p_3)^2 \\ 
-u_2 = (p_2 - p_4)^2 \\ 
-\end{gather*} 
-====Examples==== 
-Generate a list of Mandelstam and mass shell substitutions:​ 
-<sxh groovy; gutter: false> 
-def mandelstam = setMandelstam5([k1_a:​ '​m1',​ k2_a: '​m2',​ k3_a: '​m3',​ k4_a: '​m4',​ k5_a: '​m5'​]) 
-println mandelstam 
-</​sxh>​ 
-<sxh plain; gutter: false> 
-  > k1_{a}*k1^{a} = m1**2 
-  > k2_{a}*k2^{a} = m2**2 
-  > k3_{a}*k3^{a} = m3**2 
-  > k4_{a}*k4^{a} = m4**2 
-  > 2*k1_{a}*k2^{a} = s-m2**2-m1**2 
-  > 2*k4^{a}*k3_{a} = s-m3**2-m4**2 
-  > -2*k3^{a}*k1_{a} = t-m3**2-m1**2 
-  > -2*k4^{a}*k2_{a} = t-m4**2-m2**2 
-  > -2*k4^{a}*k1_{a} = -m4**2-m1**2+u 
-  > -2*k3^{a}*k2_{a} = -m3**2-m2**2+u 
-</​sxh>​ 
----- 
-Same when some particles are massless: 
-<sxh groovy; gutter: false> 
-def mandelstam = setMandelstam([k1_a:​ '​0',​ k2_a: '​m2',​ k3_a: '​m3',​ k4_a: '​0'​]) 
-println mandelstam 
-</​sxh>​ 
-<sxh plain; gutter: false> 
-   > k1_{a}*k1^{a} = 0 
-   > k2_{a}*k2^{a} = m2**2 
-   > k3_{a}*k3^{a} = m3**2 
-   > k4_{a}*k4^{a} = 0 
-   > 2*k2^{a}*k1_{a} = -m2**2+s 
-   > 2*k4^{a}*k3_{a} = -m3**2+s 
-   > -2*k3^{a}*k1_{a} = -m3**2+t 
-   > -2*k4^{a}*k2_{a} = t-m2**2 
-   > -2*k4^{a}*k1_{a} = u 
-   > -2*k2_{a}*k3^{a} = -m3**2+u-m2**2 
-</​sxh>​ 
----- 
-Specify custom notation for Mandelstam variables: 
-<sxh groovy; gutter: false> 
-def mandelstam = setMandelstam( 
-        [k1_a: '​m1',​ k2_a: '​m2',​ k3_a: '​m3',​ k4_a: '​m4'​],​ 
-        '​hS',​ '​hT',​ '​hU'​) 
-println mandelstam 
-</​sxh>​ 
-<sxh plain; gutter: false> 
-  > k1_{a}*k1^{a} = m1**2 
-  > k2_{a}*k2^{a} = m2**2 
-  > k3_{a}*k3^{a} = m3**2 
-  > k4_{a}*k4^{a} = m4**2 
-  > 2*k2^{a}*k1_{a} = -m1**2+hS-m2**2 
-  > 2*k3_{a}*k4^{a} = -m3**2+hS-m4**2 
-  > -2*k3^{a}*k1_{a} = -m3**2-m1**2+hT 
-  > -2*k2_{a}*k4^{a} = hT-m4**2-m2**2 
-  > -2*k1_{a}*k4^{a} = -m1**2+hU-m4**2 
-  > -2*k2_{a}*k3^{a} = -m3**2+hU-m2**2 
-</​sxh>​ 
- 
-====See also==== 
-  * Related tutorials: [[documentation:​tutorials:​compton_scattering_in_scalar_qed]],​ [[documentation:​tutorials:​compton_scattering_in_qed]] 
-  * JavaDocs: [[http://​api.redberry.cc/​redberry/​1.1.8/​java-api/​cc/​redberry/​physics/​feyncalc/​FeynCalcUtils.html|FeynCalcUtils]] 
-  * Source code: [[https://​bitbucket.org/​redberry/​redberry/​src/​tip/​physics/​src/​main/​java/​cc/​redberry/​physics/​feyncalc/​FeynCalcUtils.java|FeynCalcUtils.java]]