Generalized triple product $p$-adic $L$-functions and rational points on elliptic curves

We generalize and simplify the constructions of Darmon-Rotger and Hsieh of an unbalanced triple product $p$-adic $L$-function ${\mathcal{L}}_p^f(\mathit{f},\mathit{g},\mathit{h})$ attached to a triple $(\mathit{f},\mathit{g},\mathit{h})$ of $p$-adic families of modular forms, allowing more flexibility for the choice of $\mathit{g}$ and $\mathit{h}$. Assuming that $\mathit{g}$ and $\mathit{h}$ are families of theta series of infinite $p$-slope, we prove a factorization of (an improvement of) ${\mathcal{L}}_p^f(\mathit{f},\mathit{g},\mathit{h})$ in terms of two anticyclotomic $p$-adic $L$-functions. As a corollary, when $\mathit{f}$ specializes in weight $2$ to the newform attached to an elliptic curve $E$ over $\mathbb{Q}$ with multiplicative reduction at $p$, we relate certain Heegner points on $E$ to certain $p$-adic partial derivatives of ${\mathcal{L}}_p^f(\mathit{f},\mathit{g},\mathit{h})$ evaluated at the critical triple of weights $(2,1,1)$.